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  • 401.
    Mijwel, Sara
    et al.
    Karolinska Institutet.
    Cardinale, Daniele A.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Norrbom, Jessica
    Karolinska Institutet.
    Chapman, Mark
    Karolinska Institutet.
    Ivarsson, Niklas
    Karolinska Institutet.
    Wengström, Yvonne
    Karolinska Institutet.
    Sundberg, Carl Johan
    Karolinska Institutet.
    Rundqvist, Helene
    Karolinska Institutet.
    Exercise training during chemotherapy preserves skeletal muscle fiber area, capillarization, and mitochondrial content in patients with breast cancer.2018In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 32, no 10, p. 5495-5505, article id fj201700968RArticle in journal (Refereed)
    Abstract [en]

    Exercise has been suggested to ameliorate the detrimental effects of chemotherapy on skeletal muscle. The aim of this study was to compare the effects of different exercise regimens with usual care on skeletal muscle morphology and mitochondrial markers in patients being treated with chemotherapy for breast cancer. Specifically, we compared moderate-intensity aerobic training combined with high-intensity interval training (AT-HIIT) and resistance training combined with high-intensity interval training (RT-HIIT) with usual care (UC). Resting skeletal muscle biopsies were obtained pre- and postintervention from 23 randomly selected women from the OptiTrain breast cancer trial who underwent RT-HIIT, AT-HIIT, or UC for 16 wk. Over the intervention, citrate synthase activity, muscle fiber cross-sectional area, capillaries per fiber, and myosin heavy chain isoform type I were reduced in UC, whereas RT-HIIT and AT-HIIT were able to counteract these declines. AT-HIIT promoted up-regulation of the electron transport chain protein levels vs. UC. RT-HIIT favored satellite cell count vs. UC and AT-HIIT. There was a significant association between change in citrate synthase activity and self-reported fatigue. AT-HIIT and RT-HIIT maintained or improved markers of skeletal muscle function compared with the declines found in the UC group, indicating a sustained trainability in addition to the preservation of skeletal muscle structural and metabolic characteristics during chemotherapy. These findings highlight the importance of supervised exercise programs for patients with breast cancer during chemotherapy.-Mijwel, S., Cardinale, D. A., Norrbom, J., Chapman, M., Ivarsson, N., Wengström, Y., Sundberg, C. J., Rundqvist, H. Exercise training during chemotherapy preserves skeletal muscle fiber area, capillarization, and mitochondrial content in patients with breast cancer.

  • 402. Mijwel, Sara
    et al.
    Cardinale, Daniele
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Ekblom-Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Sundberg, Carl Johan
    Wengström, Yvonne
    Rundqvist, Helene
    Validation of 2 Submaximal Cardiorespiratory Fitness Tests in Patients With Breast Cancer Undergoing Chemotherapy.2016In: Rehabilitation oncology (American Physical Therapy Association. Oncology Section), ISSN 2168-3808, Vol. 34, no 4, p. 137-143Article in journal (Refereed)
    Abstract [en]

    Patients with breast cancer have an impaired cardiorespiratory fitness, in part, due to the toxic effects of anticancer therapy. Physical exercise as a means of rehabilitation for patients with cancer is an emerging area of research and treatment, emphasizing the need for accurate and feasible physical capacity measurements. The purpose of this study was to evaluate the validity of peak oxygen consumption (o2peak) predicted by the Ekblom-Bak test (E-B) and the Åstrand-Rhyming prediction model (A-R).

    METHODS: Eight patients with breast cancer undergoing chemotherapy participated in the study. Submaximal exercise tests were performed at 2 different submaximal workloads. Estimated o2peak values were obtained by inserting the heart rate (HR) from the 2 workloads into the E-B prediction model and the HR of only the higher workload into the Åstrand nomogram. A 20-W incremental cycle test-to-peak effort was performed to obtain o2peak values.

    RESULTS: Results from A-R overestimated o2peak by 6% (coefficient of variation = 7%), whereas results from E-B overestimated o2peak with 42% (coefficient of variation = 21%) compared with measured o2peak. Pearson's correlation coefficient revealed a significant strong relationship between the estimated o2peak from A-R and the measured o2peak (r = 0.86; P < .05), whereas the relationship between the estimated o2peak from E-B and the measured o2peak resulted in a nonsignificant weak correlation (r = 0.21).

    CONCLUSION: In a situation where maximal exercise testing is not practical or undesirable from a patient safety perspective, submaximal exercise testing provides an alternative way of estimating o2peak. The A-R prediction model appears to be a valid submaximal exercise test for determining cardiorespiratory fitness in this population.

  • 403.
    Millischer, Vincent
    et al.
    Karolinska institutet.
    Erhardt, Sophie
    Karolinska institutet.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Forsell, Yvonne
    Karolinska institutet.
    Lavebratt, Catharina
    Karolinska institutet.
    Twelve-week physical exercise does not have a long-lasting effect on kynurenines in plasma of depressed patients2017In: Neuropsychiatric Disease and Treatment, ISSN 1176-6328, E-ISSN 1178-2021, Vol. 13, p. 967-972Article in journal (Refereed)
    Abstract [en]

    Background: Physical exercise has well-characterized positive effects on depressive symptoms. The underlying biologic mechanisms are, however, far from established. A recently discovered mechanism has linked the enhanced conversion of kynurenine to kynurenic acid (KYNA) to an increased resilience toward stress-induced depression in mice. The aim of this study was to translate these findings to humans.

    Materials and methods: Kynurenine and KYNA levels were measured by high-performance liquid chromatography in plasma samples from 117 patients affected by mild-to-moderate depression before and within a week after a 12-week training period at three different intensities. The patients were part of the Regassa study.

    Results: No differences in plasma levels of kynurenine and KYNA or in their ratio could be detected between before and after training. No effect of the intensity group could be observed. No correlation with the improvement in cardiovascular fitness (Åstrand score) or the improvement in mood (Montgomery Åsberg Depression Rating Scale score) could be observed.

    Limitations: As the Regassa study is based on an intention-to-treat protocol, the exact time and the exact intensity of the physical exercise are not known. Analyses of pulse data as well as personal interviews, however, were used to control the exercise protocols. Furthermore, the observations reflect chronic changes.

    Conclusion: Physical exercise positively affects mood and cardiovascular fitness, but does not lead to long-lasting changes in plasma levels of kynurenine and KYNA in patients affected by mild-to-moderate depression.

  • 404.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    ACSM Annual Meeting: Två dagar med fokus på muskelhypertrofi/atrofi2018In: Idrottsmedicin, ISSN 2001-3302, Vol. 37, no 3, p. 29-31Article in journal (Other (popular science, discussion, etc.))
  • 405.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Effects of exercise and amino acid intake on mechanisms regulating protein synthesis and breakdown in human muscle2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Skeletal muscle adapts differently to specific modes of exercise, where resistance training results in muscle growth and endurance training induces mitochondrial biogenesis. These are results of molecular events that occur after each exercise session, increasing the expression of specific genes and the rate of both synthesis and breakdown of protein. The rate of protein synthesis is controlled by the mTORC1 signaling pathway, which is potently stimulated by resistance exercise and amino acid, and their combined effect is needed for muscle growth. The essential amino acids (EAA) are responsible for the stimulation of protein synthesis and here leucine has been attributed specific attention, but its particular role among the EAA, and the involvement of the other branched-chain amino acids (BCAA) is unclear. Endurance exercise activates the protein AMPK which, in animal models, has been shown to inhibit mTORC1 signaling and protein synthesis.  Suggesting that concurrent endurance and resistance exercise could restrain muscle growth, but it is unknown if this mechanism is relevant in exercising human muscle. Little is known about the regulation of protein breakdown and although much attention has been given the proteins MuRF-1 and MAFbx which target proteins for degradation, their role requires further investigation. The aim of thesis was to address the mentioned uncertainties by examining how different modes of exercise and amino acids affect mTORC1 signaling, protein synthesis and markers of protein breakdown in human muscle.

    In study I, the influence of high intensity endurance exercise on subsequent resistance exercised induced mTORC1 signaling was examined. Despite robust activation of AMPK by the endurance exercise there was no inhibition of mTORC1 signaling or protein synthesis during recovery from resistance exercise. Study II utilized a similar set up, but with the difference that resistance exercise was performed with the triceps. The cycling exercise reduced the resistance exercise stimulated mTORC1 signaling immediately after the exercise, but during the recovery period mTORC1 signaling and protein synthesis was similar between trials. Concurrent exercise induced the mRNA expression of MuRF-1 and that of PGC-1α, the master regulator of mitochondrial biogenesis, in both studies, despite that the exercise modes in study II were separated between legs and arms. In study III, the effect of an EAA supplement with or without leucine, in the stimulation of mTORC1 signaling in connection with resistance exercise was examined. Intake of EAA robustly stimulated mTORC1 signaling after exercise, but this was only minor when leucine was excluded from the supplement. In study IV, subjects were supplied with leucine, BCAA, EAA or placebo in a randomized fashion during four sessions of resistance exercise. Leucine alone stimulated mTORC1 signaling after the exercise, but both the amplitude and extent of stimulation was substantially greater with EAA, an effect that was largely mediated by the BCAA as a group.

    In conclusion, endurance exercise prior to resistance exercise using the leg or arm muscles does not affect mTORC1 signaling or protein synthesis during the three hour recovery period from exercise, supporting compatibility between resistance- and endurance exercise induced signaling. Concurrent exercise increases the expression of the proteolytic marker MuRF-1 compared to resistance exercise only, which could indicate both and increased demand of cellular adaptive remodeling or a more direct detrimental proteolytic effect. Leucine is crucial among the EAA in the stimulation of mTORC1 signaling after exercise, its effect is however potentiated by intake of the remaining EAA. As a supplement a mixture of EAA must be regarded preferable, although the effect is largely mediated by the BCAA as a group.  

     

  • 406.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Effekt av kombinerad styrke- och konditionsträning2018In: Idrottsmedicin, ISSN 2001-3302, Vol. 37, no 3, p. 8-9Article in journal (Other academic)
    Abstract [sv]

    Det finns teorier om att kombinerad konditions- och styrketräning hämmar styrkeutvecklingen jämfört med enbart styrketräning. För att ta reda på om det stämmer genomfördes studier där cykling kombinerades med styrketräning.

  • 407.
    Moberg, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Apró, William
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Aminosyror ökar träningseffekten2013In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 22, no 1, p. 45-49Article in journal (Other academic)
    Abstract [sv]

    Kostens sammansättning är viktig för prestation och återhämtning. Dess innehåll av protein och essentiella aminosyror kan påverka musklernas anpassning till träning. Ny forskning visar att vissa aminosyror har en viktigare roll än att enbart agera som byggstenar eller energigivande näringsämnen.

  • 408.
    Moberg, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Apró, William
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    High-intensity cycling performed prior to resistance exercise does not influence mTORC1-signaling and the rate of muscle protein synthesis in the triceps brachii2014Conference paper (Other academic)
    Abstract [en]

    Introduction

    Endurance exercise can influence strength training adaptations when performed concurrently, with both inhibition (Kreamer 1995) and augmentation (Lundberg 2012) of muscular hypertrophy being reported. Our lab has set out to conduct a series of studies to examine the influence of endurance exercise on the acute stimulatory effect of resistance exercise on anabolic processes. In the present study, the effect of endurance exercise on a previously inactive muscle was investigated. The aim was to examine the influence of resistance exercise on mTORC1-signaling and rate of protein synthesis in the triceps brachii muscle with or without preceding intervals of high-intensity cycling. 

     

    Methods

    Eight trained males performed, in a randomized fashion, two sessions of heavy resistance exercise (RE) with the triceps muscles, where one session was preceded by intervals of high-intensity cycling (E+RE), 5 x 4 min at 85% of VO2 peak. Mixed muscle protein fractional synthetic rate (FSR) was measured at rest, prior to exercise, and during a 3 hour recovery period following exercise by continuous infusion of L-[ring-13C6] phenylalanine. Muscle biopsies from the triceps brachii was collected twice at rest separated by three hours, directly after resistance exercise and following 90 and 180 min of recovery. Signalling in the mTORC1-and AMPK-pathway was assessed using western blot technique.

     

    Results

    The same amount of work with regard to load, total number of repetitions and total time under tension was performed in the two trials. Muscle protein FSR increased from 0.050 ± 0.006 %/h at rest to 0.078 ± 0.008 and 0.082 ± 0.0016 %/h following E+RE and RE, respectively, with no difference between trials. Phosphorylation (P) of AMPKT172 was increased by 45-65% directly after exercise, similarly in both conditions, and regressed to a level approx. 20% lower than baseline following 180 min of recovery. P-mTORS2448 was increased 76 and 108% above rest directly after the E+RE and RE, respectively, and remained elevated in both trials during the entire recovery period. P-eEF2T56 was 20-36% higher directly after exercise but fell to a level that was 30-36% lower than pre-exercise and remained reduced during the entire recovery, with no difference between trials.

     

    Conclusion

    High-intensity endurance cycling does not influence the acute stimulation of anabolic signalling and muscle protein synthesis in the triceps brachii following resistance exercise.

     

     

    References

    Kreamer WJ et al. (1995) J Appl Physiol 78(3):976-989

    Lundberg T et al. (2013) J Appl Physiol 114: 81-89

  • 409.
    Moberg, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Apró, William
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Gerrit, van Hall
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Activation of mTORC1 by leucine is potentiated by branched chain amino acids and even more so by essential amino acids following resistance exercise2016In: American Journal of Physiology - Cell Physiology, ISSN 0363-6143, E-ISSN 1522-1563, Vol. 310, no 11, p. C874-C884Article in journal (Refereed)
    Abstract [en]

    Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mTORC1 signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo, leucine, BCAA or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6K1 was greater than at rest in all four trials (Placebo<Leucine<BCAA<EAA; P<0.05 time x supplement), with a 9-fold increase in the EAA trial. At this same time-point phosphorylation of 4E-BP1 at Thr37/46 was unaffected by supplementation, while that of Thr46 alone exhibited a pattern similar to that of S6K1, being 18% higher with EAA than BCAA. However, after 180 min of recovery this difference between EAA and BCAA had disappeared, although with both these supplements the increases were still higher than with leucine (40%, P<0.05) and placebo (100%, P<0.05). In summary, EAA ingestion appears to stimulate translation initiation more effectively than the other supplements, although the results also suggest that this effect is primarily attributable to the BCAA.

  • 410.
    Moberg, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Apró, William
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Ohlsson, Inger
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Villanueva, Antonio
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Absence of leucine in an essential amino acid supplement reduces activation of mTORC1 signalling following resistance exercise in young females.2014In: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320, Vol. 39, no 2, p. 183-94Article in journal (Refereed)
    Abstract [en]

    The purpose of the study was to investigate the specific effect of leucine on mTORC1 signalling and amino acid metabolism in connection with resistance exercise. Comparisons were made between ingestion of supplements with and without leucine. Eight young women performed leg press exercise on 2 occasions. In randomized order they received either an aqueous solution of essential amino acids with leucine (EAA) or without leucine (EAA-Leu), given as small boluses throughout the experiment. Muscle biopsies were taken after an overnight fast before exercise and 1 and 3 h postexercise and samples of blood were taken repeatedly during the experiment. Plasma and muscle concentrations of leucine rose 60%-140% (p < 0.05) with EAA and fell 35%-45% (p < 0.05) with the EAA-Leu supplement. In the EAA-trial, plasma and muscle levels of tyrosine (not present in the supplement) and the sum of the EAA were 15%-25% (p < 0.05) lower during recovery. Phosphorylation of mTOR and p70S6k was elevated to a larger extent following 1 h of recovery with leucine in the supplement (120% vs. 49% (p < 0.05) and 59- vs. 8-fold (p < 0.05) for EAA and EAA-Leu, respectively). The levels of MAFbx and MuRF-1 mRNA and of the corresponding proteins were not significantly altered after 3 h recovery from exercise. In conclusion, the presence of leucine in the supplement enhances the stimulatory effect on mTORC1 signalling and reduces the level of tyrosine and the sum of the EAA in muscle and plasma, suggesting a stimulation of protein synthesis and (or) inhibition of breakdown, leading to improvement in net protein balance.

  • 411.
    Moberg, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Hendo, Gina
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Jakobsson, Madeleine
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Ekblom Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Increased autophagy signalling but not proteasome activity in human skeletal muscle after prolonged low-intensity exercise with negative energy balance2017In: ICSPP Abstracts: Journal of Science and Medicine in Sport, Volume 20, Supplement 2, November 2017, Pages S166, 2017, Vol. 20, no Supplement 2, p. S166-, article id 287Conference paper (Other academic)
  • 412.
    Moberg, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Hendo, Gina
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Jakobsson, Madelene
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Mattsson, C Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom-Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Increased autophagy signaling but not proteasome activity in human skeletal muscle after prolonged low-intensity exercise with negative energy balance2017In: Physiological Reports, E-ISSN 2051-817X, Vol. 5, no 23, article id e13518Article in journal (Refereed)
    Abstract [en]

    Little is known about the molecular regulation of skeletal muscle protein turnover during exercise in field conditions where energy is intake inadequate. Here, 17 male and 7 female soldiers performed an 8 day long field based military operation. Vastus lateralis muscle biopsies, in which autophagy, the ubiquitin-proteasome system and the mTORC1 signaling pathway where studied, were collected before and after the operation. The 187 h long operation resulted in a 15% and 29% negative energy balance as well as a 4.1% and 4.6% loss of body mass in women and men respectively. After the operation protein levels of ULK1 as well as the phosphorylation of ULK1Ser317 and ULK1Ser555 had increased by 11%, 39% and 13%, respectively, and this was supported by a 17% increased phosphorylation of AMPKThr172 (P<0.05). The LC3b-I/II ratio was 3-fold higher after compared to before the operation (P<0.05), whereas protein levels of p62/SQSTM1 were unchanged. The β1, β2, and β5 activity of the proteasome and protein levels of MAFbx did not change, while levels of MuRF-1 were slightly reduced (6%, P<0.05). Protein levels and phosphorylation status of key components in the mTORC1 signaling pathway remained at basal levels after the operation. Muscle levels of glycogen decreased from 269±12 to 181±9 mmol ∙ kg dry muscle-1 after the exercise period (P<0.05). In conclusion, the 8 days of field based exercise resulted in induction of autophagy without any increase in proteasome activity or protein ubiquitination. Simultaneously, the regulation of protein synthesis through the mTORC1 signaling pathway was maintained.

  • 413. Mogensen, M
    et al.
    Vind, B F
    Højlund, K
    Beck-Nielsen, H
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Maximal lipid oxidation in patients with type 2 diabetes is normal and shows an adequate increase in response to aerobic training.2009In: Diabetes, obesity and metabolism, ISSN 1462-8902, E-ISSN 1463-1326, Vol. 11, no 9, p. 874-83Article in journal (Refereed)
    Abstract [en]

    AIM: Insulin resistance in subjects with type 2 diabetes (T2D) and obesity is associated with an imbalance between the availability and the oxidation of lipids. We hypothesized that maximal whole-body lipid oxidation during exercise (FATmax) is reduced and that training-induced metabolic adaptation is attenuated in T2D. METHODS: Obese T2D (n = 12) and control (n = 11) subjects matched for age, sex, physical activity and body mass index completed 10 weeks of aerobic training. Subjects were investigated before and after training with maximal and submaximal exercise tests and euglycaemic-hyperinsulinaemic clamps combined with muscle biopsies. RESULTS: Training increased maximal oxygen consumption (VO(2max)) and muscle citrate synthase activity and decreased blood lactate concentrations during submaximal exercise in both groups (all p < 0.01). FATmax increased markedly (40-50%) in both T2D and control subjects after training (all p < 0.001). There were no significant differences in these variables and lactate threshold (%VO(2max)) between groups before or after training. Insulin-stimulated glucose disappearance rate (Rd) was lower in T2D vs. control subjects both before and after training. Rd increased in response to training in both groups (all p < 0.01). There was no correlation between Rd and measures of oxidative capacity or lipid oxidation during exercise or the training-induced changes in these parameters. CONCLUSIONS: FATmax was not reduced in T2D, and muscle oxidative capacity increased adequately in response to aerobic training in obese subjects with and without T2D. These metabolic adaptations to training seem to be unrelated to changes in insulin sensitivity and indicate that an impaired capacity for lipid oxidation is not a major cause of insulin resistance in T2D.

  • 414. Mogensen, Martin
    et al.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Mitochondrial efficiency in rat skeletal muscle: influence of respiration rate, substrate and muscle type.2006In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 185, p. 229-236Article in journal (Refereed)
    Abstract [en]

    Aim: To investigate the hypothesis that mitochondrial efficiency (i.e. P/O ratio) is higher in type I than in type II fibres during submaximal rates of respiration.

    Methods: Mitochondria were isolated from rat soleus and extensor digitorum longus (EDL) muscles, representing type I and type II fibres, respectively. Mitochondrial efficiency (P/O ratio) was determined with pyruvate (Pyr) or palmitoyl-L-carnitine (PC) during submaximal (constant rate of ADP infusion) and maximal (Vmax, state 3) rates of respiration and fitted to monoexponential functions.

    Results: There was no difference in Vmax between PC and Pyr in soleus but in EDL Vmax with PC was only 58% of that with Pyr. The activity of 3-hydroxyacyl-CoA dehydrogenase (HAD) was 3-fold higher in soleus than in EDL. P/O ratio at Vmax was 8-9% lower with PC (2.33±0.02 (soleus) and 2.30±0.02 (EDL)) than with Pyr (2.52±0.03 (soleus) and 2.54±0.03 (EDL)) but not different between the two muscles (P>0.05). P/O ratio was low at low rates of respiration and increased exponentially when the rate of respiration increased. The asymptotes of the curves were similar to P/O ratio at Vmax. P/O ratio at submaximal respirations was not different between soleus and EDL neither with Pyr nor with PC.

    Conclusion: Mitochondrial efficiency, as determined in vitro, was not significantly different in the two fibre types neither at Vmax nor at submaximal rates of respiration. The low Vmax for PC oxidation in EDL may relate to low activity of β-oxidation.

  • 415.
    Mogensen, Martin
    et al.
    University of Southern Denmark, Odense, Denmark.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll. University of Southern Denmark, Odense, Denmark.
    Fernström, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology. Karolinska institutet.
    Glintborg, Dorte
    Odense University Hospital, Odense, Denmark.
    Vind, Birgitte F
    Odense University Hospital, Odense, Denmark.
    Beck-Nielsen, Henning
    Odense University Hospital, Odense, Denmark.
    Højlund, Kurt
    Odense University Hospital, Odense, Denmark.
    Mitochondrial respiration is decreased in skeletal muscle of patients with type 2 diabetes.2007In: Diabetes, ISSN 0012-1797, E-ISSN 1939-327X, Vol. 56, no 6, p. 1592-9Article in journal (Refereed)
    Abstract [en]

    We tested the hypothesis of a lower respiratory capacity per mitochondrion in skeletal muscle of type 2 diabetic patients compared with obese subjects. Muscle biopsies obtained from 10 obese type 2 diabetic and 8 obese nondiabetic male subjects were used for assessment of 3-hydroxy-Acyl-CoA-dehydrogenase (HAD) and citrate synthase activity, uncoupling protein (UCP)3 content, oxidative stress measured as 4-hydroxy-2-nonenal (HNE), fiber type distribution, and respiration in isolated mitochondria. Respiration was normalized to citrate synthase activity (mitochondrial content) in isolated mitochondria. Maximal ADP-stimulated respiration (state 3) with pyruvate plus malate and respiration through the electron transport chain (ETC) were reduced in type 2 diabetic patients, and the proportion of type 2X fibers were higher in type 2 diabetic patients compared with obese subjects (all P < 0.05). There were no differences in respiration with palmitoyl-l-carnitine plus malate, citrate synthase activity, HAD activity, UCP3 content, or oxidative stress measured as HNE between the groups. In the whole group, state 3 respiration with pyruvate plus malate and respiration through ETC were negatively associated with A1C, and the proportion of type 2X fibers correlated with markers of insulin resistance (P < 0.05). In conclusion, we provide evidence for a functional impairment in mitochondrial respiration and increased amount of type 2X fibers in muscle of type 2 diabetic patients. These alterations may contribute to the development of type 2 diabetes in humans with obesity.

  • 416. Montenegro, Marcelo F
    et al.
    Sundqvist, Michaela L
    Larsen, Filip J
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Zhuge, Zhengbing
    Carlström, Mattias
    Weitzberg, Eddie
    Lundberg, Jon O
    Blood Pressure-Lowering Effect of Orally Ingested Nitrite Is Abolished by a Proton Pump Inhibitor.2017In: Hypertension, ISSN 0194-911X, E-ISSN 1524-4563, Vol. 69, no 1, p. 23-31Article in journal (Refereed)
    Abstract [en]

    Inorganic nitrate and nitrite from dietary and endogenous sources are metabolized to NO and other bioactive nitrogen oxides that affect blood pressure. The mechanisms for nitrite bioactivation are unclear, but recent studies in rodents suggest that gastric acidity may influence the systemic effects of this anion. In a randomized, double-blind, placebo-controlled crossover study, we tested the effects of a proton pump inhibitor on the acute cardiovascular effects of nitrite. Fifteen healthy nonsmoking, normotensive subjects, aged 19 to 39 years, were pretreated with placebo or esomeprazole (3×40 mg) before ingesting sodium nitrite (0.3 mg kg(-1)), followed by blood pressure monitoring. Nitrite reduced systolic blood pressure by a maximum of 6±1.3 mm Hg when taken after placebo, whereas pretreatment with esomeprazole blunted this effect. Peak plasma nitrite, nitrate, and nitroso species levels after nitrite ingestion were similar in both interventions. In 8 healthy volunteers, we then infused increasing doses of sodium nitrite (1, 10, and 30 nmol kg(-1) min(-1)) intravenously. Interestingly, although plasma nitrite peaked at similar levels as with orally ingested nitrite (≈1.8 µmol/L), no changes in blood pressure were observed. In rodents, esomeprazole did not affect the blood pressure response to the NO donor, DEA NONOate, or vascular relaxation to nitroprusside and acetylcholine, demonstrating an intact downstream NO-signaling pathway. We conclude that the acute blood pressure-lowering effect of nitrite requires an acidic gastric environment. Future studies will reveal if the cardiovascular complications associated with the use of proton pump inhibitors are linked to interference with the nitrate-nitrite-NO pathway.

  • 417.
    Moretti, Chiara
    et al.
    Karolinska Inst, Dept Physiol & Pharmacol, Stockholm, Sweden..
    Larsen, Filip J
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Lundberg, Jon
    Karolinska Inst, Dept Physiol & Pharmacol, Stockholm, Sweden..
    Dietary nitrite extends lifespan in the fruit fly2019In: European Journal of Clinical Investigation,  Vol 49, Suppl 1, p 102, Meeting Abstract: P004-T, Wiley-Blackwell, 2019, Vol. 49, p. 102-102Conference paper (Other academic)
  • 418. Mortensen, Stefan P
    et al.
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    High-density lipoprotein: a new therapeutic target for glucose intolerance?2013In: Circulation, ISSN 0009-7322, E-ISSN 1524-4539, Vol. 128, no 22, p. 2349-50Article in journal (Other academic)
    Abstract [en]

    Editorial. The article discusses research being done on apolipoprotein A-I (ApoA-I). It references the study "High-Density Lipoprotein Maintains Skeletal Muscle Function by Modulating Cellular Respiration in Mice," by M. Lehti et al. published in the 2013 issue of "Circulation." It is hypothesized that understanding the importance of the mechanistic links between high-density lipoprotein (HDL) and energy metabolism would contribute to the prevention and treatment of type 2 diabetes mellitus.

  • 419. Newsholme, Eric A
    et al.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Branched-chain amino acids and central fatigue.2006In: Journal of Nutrition, ISSN 0022-3166, E-ISSN 1541-6100, Vol. 136, no 1 Suppl, p. 274S-6SArticle in journal (Refereed)
    Abstract [en]

    An account of the tryptophan (Trp)-5-hydroxytryptamine (5-HT)-central fatigue theory is provided and an explanation of how oral administration of BCAAs can decrease fatigue on the basis of this theory is given. The rate-limiting step in the synthesis of 5-HT is the transport of Trp across the blood-brain barrier. This transport is influenced by the fraction of Trp available for transport into the brain and the concentration of the other large neutral amino acids, including the BCAAs, which are transported via the same carrier system. During endurance exercise, there is an uptake of Trp by the brain, suggesting that this may increase the synthesis and release of 5-HT in the brain. Oral intake of BCAAs may reduce this uptake and also brain 5-HT synthesis and release, thereby delaying fatigue. Other hypotheses for the effect of BCAAs on central fatigue are included.

  • 420. Nielsen, Joachim
    et al.
    Mogensen, Martin
    Vind, Birgitte F
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Højlund, Kurt
    Schrøder, Henrik D
    Ortenblad, Niels
    Increased subsarcolemmal lipids in type 2 diabetes: effect of training on localization of lipids, mitochondria, and glycogen in sedentary human skeletal muscle.2010In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 298, no 3, p. E706-13Article in journal (Refereed)
    Abstract [en]

    The purpose of the study was to investigate the effect of aerobic training and type 2 diabetes on intramyocellular localization of lipids, mitochondria, and glycogen. Obese type 2 diabetic patients (n = 12) and matched obese controls (n = 12) participated in aerobic cycling training for 10 wk. Endurance-trained athletes (n = 15) were included for comparison. Insulin action was determined by euglycemic-hyperinsulinemic clamp. Intramyocellular contents of lipids, mitochondria, and glycogen at different subcellular compartments were assessed by transmission electron microscopy in biopsies obtained from vastus lateralis muscle. Type 2 diabetic patients were more insulin resistant than obese controls and had threefold higher volume of subsarcolemmal (SS) lipids compared with obese controls and endurance-trained subjects. No difference was found in intermyofibrillar lipids. Importantly, following aerobic training, this excess SS lipid volume was lowered by approximately 50%, approaching the levels observed in the nondiabetic subjects. A strong inverse association between insulin sensitivity and SS lipid volume was found (r(2)=0.62, P = 0.002). The volume density and localization of mitochondria and glycogen were the same in type 2 diabetic patients and control subjects, and showed in parallel with improved insulin sensitivity a similar increase in response to training, however, with a more pronounced increase in SS mitochondria and SS glycogen than in other localizations. In conclusion, this study, estimating intramyocellular localization of lipids, mitochondria, and glycogen, indicates that type 2 diabetic patients may be exposed to increased levels of SS lipids. Thus consideration of cell compartmentation may advance the understanding of the role of lipids in muscle function and type 2 diabetes.

  • 421.
    Nilsson, Avlant
    et al.
    Chalmers University of Technology, Gothenburg, Sweden.
    Björnson, Elias
    Chalmers University of Technology, Gothenburg, Sweden.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Larsen, Filip J
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Nielsen, Jens
    Chalmers University of Technology, Gothenburg, Sweden.
    Complex I is bypassed during high intensity exercise.2019In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, no 1, article id 5072Article in journal (Refereed)
    Abstract [en]

    Human muscles are tailored towards ATP synthesis. When exercising at high work rates muscles convert glucose to lactate, which is less nutrient efficient than respiration. There is hence a trade-off between endurance and power. Metabolic models have been developed to study how limited catalytic capacity of enzymes affects ATP synthesis. Here we integrate an enzyme-constrained metabolic model with proteomics data from muscle fibers. We find that ATP synthesis is constrained by several enzymes. A metabolic bypass of mitochondrial complex I is found to increase the ATP synthesis rate per gram of protein compared to full respiration. To test if this metabolic mode occurs in vivo, we conduct a high resolved incremental exercise tests for five subjects. Their gas exchange at different work rates is accurately reproduced by a whole-body metabolic model incorporating complex I bypass. The study therefore shows how proteome allocation influences metabolism during high intensity exercise.

  • 422. Nilsson, Hanna
    et al.
    Angerås, Ulf
    Bock, David
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Onerup, Aron
    Fagevik Olsen, Monika
    Gellerstedt, Martin
    Haglind, Eva
    Angenete, Eva
    Is preoperative physical activity related to post-surgery recovery? A cohort study of patients with breast cancer.2016In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 6, no 1, article id e007997Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The aim of our study is to assess the association between preoperative level of activity and recovery after breast cancer surgery measured as hospital stay, length of sick leave and self-assessed physical and mental recovery.

    DESIGN: A prospective cohort study.

    SETTING: Patients included were those scheduled to undergo breast cancer surgery, between February and November 2013, at two participating hospitals in the Western Region of Sweden.

    PARTICIPANTS: Patients planned for breast cancer surgery filled out a questionnaire before, as well as at 3 and 6 weeks after the operation. The preoperative level of activity was self-assessed and categorised into four categories by the participants using the 4-level Saltin-Grimby Physical Activity Level Scale (SGPALS).

    MAIN OUTCOME MEASURE: Our main outcome was postoperative recovery measured as length of sick leave, in-hospital stay and self-assessed physical and mental recovery.

    RESULTS: 220 patients were included. Preoperatively, 14% (31/220) of participants assessed themselves to be physically inactive, 61% (135/220) to exert some light physical activity (PA) and 20% (43/220) to be more active (level 3+4). Patients operated with mastectomy versus partial mastectomy and axillary lymph node dissection versus sentinel node biopsy were less likely to have a short hospital stay, relative risk (RR) 0.88 (0.78 to 1.00) and 0.82 (0.70 to 0.96). More active participants (level 3 or 4) had an 85% increased chance of feeling physically recovered at 3 weeks after the operation, RR 1.85 (1.20 to 2.85). No difference was seen after 6 weeks.

    CONCLUSIONS: The above study shows that a higher preoperative level of PA is associated with a faster physical recovery as reported by the patients 3 weeks post breast cancer surgery. After 6 weeks, most patients felt physically recovered, diminishing the association above. No difference was seen in length of sick leave or self-assessed mental recovery between inactive or more active patients.

  • 423.
    Nilsson, Lina
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Apro, William
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Larsen, Filip J
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Biphasic relationship between training load and glucose tolerance2019Conference paper (Other academic)
    Abstract [sv]

    Biphasic relationship between training load and glucose tolerance

    Nilsson, L, Flockhart M, Bergman K, Apro W, Ekblom B, Larsen FJ

     

    There is a well-established construct regarding the positive effects of exercise on glucose tolerance and insulin sensitivity, as well as muscle glycogen storage. In insulin resistance, physical activity is an essential part of the treatment. However, the optimal dose is unknown. Reduced muscular glycogen stores, resulting from exercise, should stimulate an increased uptake of blood glucose. In this study we investigated the relation between training load, glucose tolerance and insulin sensitivity during three weeks of increasing interval training. Three times during the intervention, oral glucose tests were conducted to investigate the rate of glucose uptake. We found a biphasic dose-response relationship between training load and glucose tolerance, where an excessive training load led to a paradoxical reduction in glucose tolerance and impaired insulin release despite an unchanged amount of muscle glycogen. In light of these results, an upper limit of physical exercise exist where the negative effects overpowers the positive.

  • 424.
    Nooijen, Carla F J
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Blom, Victoria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Sport Psychology research group.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Improving office workers' mental health and cognition: a 3-arm cluster randomized controlled trial targeting physical activity and sedentary behavior in multi-component interventions2019In: BMC Public Health, ISSN 1471-2458, E-ISSN 1471-2458, Vol. 19, article id 266Article in journal (Refereed)
    Abstract [en]

    Background

    Physically inactive and sedentary lifestyles are negatively related to both mental health and cognition. For office-workers, who spend two-thirds of their workday sitting, it is important to improve these lifestyles. The aim of this study is to assess the effectiveness of multi-component interventions, incorporating individual, environmental and organizational changes, to increase physical activity or reduce sedentary behavior among office-workers in order to improve mental health and cognition.

    Methods

    a 3-arm, clustered randomized controlled trial (RCT) with waiting list control group amongst adult office-workers of two large Swedish companies. Cluster teams will be randomized into 6-month interventions or to a passive waiting list control group which will receive the allocated intervention with a 6-month delay. Two multicomponent interventions will be studied of which one focuses on improving physical activity and the other on reducing sedentary behavior. Both interventions include 5 sessions of motivational counselling. In the physical activity intervention persons also get access to a gym and team leaders will organize lunch walks and encourage to exercise. In the sedentary behavior intervention standing- and walking meetings will be implemented and team leaders will encourage to reduce sitting. The recruitment target is 110 office-workers per arm (330 in total). Measurements will be repeated every 6months for a total intended duration of 24months. Proximal main outcomes are physical activity measured with accelerometers and sedentary behavior with inclinometers. Distal outcomes are self-reported mental health and a cognition test battery. Additional outcomes will include cardiovascular fitness, body composition, sleep, self-reported physical activity and sedentary behavior, other health habits, physical health, and working mechanisms from blood samples and questionnaires.

    Discussion

    This cluster RCT will contribute to the currently available evidence by comparing the effectiveness of multi-component interventions targeting physical activity or sedentary behavior with the end goal of improving mental health and cognition. This study is strong in its cluster randomized design, numerous objective outcome measures and long-term follow-up. The exact content of the interventions has been defined by combining theory with results from a larger research project as well as having a continuous dialogue with the involved companies.

  • 425.
    Nooijen, Carla F J
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences. Karolinska Institutet.
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Blom, Victoria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Sport Psychology research group. Karolinska Institutet.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Forsell, Yvonne
    Karolinska Institutet.
    Ekblom, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control. Karolinska Institutet.
    Common Perceived Barriers and Facilitators for Reducing Sedentary Behaviour among Office Workers.2018In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 15, no 4, article id E792Article in journal (Refereed)
    Abstract [en]

    Qualitative studies identified barriers and facilitators associated with work-related sedentary behaviour. The objective of this study was to determine common perceived barriers and facilitators among office workers, assess subgroup differences, and describe sedentary behaviour. From two Swedish companies, 547 office workers (41 years (IQR = 35–48), 65% women, 66% highly educated) completed questionnaires on perceived barriers and facilitators, for which subgroup differences in age, gender, education, and workplace sedentary behaviour were assessed. Sedentary behaviour was measured using inclinometers (n = 311). The most frequently reported barrier was sitting is a habit (67%), which was reported more among women than men (X2 = 5.14, p = 0.03) and more among highly sedentary office workers (X2 = 9.26, p < 0.01). The two other most reported barriers were that standing is uncomfortable (29%) and standing is tiring (24%). Facilitators with the most support were the introduction of either standing- or walking-meetings (respectively 33% and 29%) and more possibilities or reminders for breaks (31%). The proportion spent sedentary was 64% at the workplace, 61% on working days, and 57% on non-working days. This study provides a detailed understanding of office workers’ ideas about sitting and means to reduce sitting. We advise to include the supported facilitators and individualized support in interventions to work towards more effective strategies to reduce sedentary behaviour.

  • 426.
    Nooijen, Carla F J
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Blom, Victoria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Sport Psychology research group.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Forsell, Yvonne
    Karolinska Institutet.
    Ekblom, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Common perceived barriers and facilitators for reducing sedentary behaviour among office-workers2018In: Journal of Physical Activity & Health, Volume 15, Issue 10, Pages S94-S95 Supplement 1, Canadian Consortium on Human Security, 2018, Vol. 15, no 10, p. S94-S95Conference paper (Other academic)
  • 427. Nordsborg, N B
    et al.
    Robach, P
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Calbet, J A L
    Lundby, C
    Erythropoietin does not reduce plasma lactate, H(+) , and K(+) during intense exercise.2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no 6, p. e566-e575Article in journal (Refereed)
    Abstract [en]

    It is investigated if recombinant human erythropoietin (rHuEPO) treatment for 15 weeks (n = 8) reduces extracellular accumulation of metabolic stress markers such as lactate, H(+) , and K(+) during incremental exhaustive exercise. After rHuEPO treatment, normalization of blood volume and composition by hemodilution preceded an additional incremental test. Group averages were calculated for an exercise intensity ∼80% of pre-rHuEPO peak power output. After rHuEPO treatment, leg lactate release to the plasma compartment was similar to before (4.3 ± 1.6 vs 3.9 ± 2.5 mmol/min) and remained similar after hemodilution. Venous lactate concentration was higher (P < 0.05) after rHuEPO treatment (7.1 ± 1.6 vs 5.2 ± 2.1 mM). Leg H(+) release to the plasma compartment after rHuEPO was similar to before (19.6 ± 5.4 vs 17.6 ± 6.0 mmol/min) and remained similar after hemodilution. Nevertheless, venous pH was lower (P < 0.05) after rHuEPO treatment (7.18 ± 0.04 vs 7.22 ± 0.05). Leg K(+) release to the plasma compartment after rHuEPO treatment was similar to before (0.8 ± 0.5 vs 0.7 ± 0.7 mmol/min) and remained similar after hemodilution. Additionally, venous K(+) concentrations were similar after vs before rHuEPO (5.3 ± 0.3 vs 5.1 ± 0.4 mM). In conclusion, rHuEPO does not reduce plasma accumulation of lactate, H(+) , and K(+) at work rates corresponding to ∼80% of peak power output.

  • 428.
    Nyberg, Gisela
    et al.
    Karolinska institutet.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Stillasittande hos barn och ungdomar2013In: Långvarigt stillasittande: en hälsofara i tiden / [ed] Elin Ekblom Bak, 2013, p. 57-78Chapter in book (Other academic)
  • 429. Nyberg, Gisela
    et al.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Marcus, Claude
    A 4-Year Cluster-Randomised Controlled Intervention Study on Physical Activity Pattern and Sedentary Behaviour in Children2011In: Medicine and Science in Sport and Exercise, 2011, Vol. 43, suppl 15, p. 24-24Conference paper (Refereed)
    Abstract [en]

    PURPOSE: The purpose of the present study was to examine the effects of a cluster-randomised, controlled school-based intervention (the STOPP-study) on objectively measured sedentary time, time spent in light intensity activity and in moderate to vigorous physical activity (MVPA).

    METHODS: A total of 1538 children in grades 1-4 from ten selected schools in Stockholm county area were included. Schools were randomised as intervention (n=5) or control (n=5). Physical activity was aimed to increase by 30 min -1day during school time and sedentary behavior was restricted during after school care time. Physical activity was measured by accelerometry. Percentage of time spent sedentary (below 1.5 METs), in light (between 1.5 and 3 METs), and in MVPA (above 3 METs) were primary outcome variables.

    RESULTS: Adjusted for age, gender and calendar year, children in intervention schools spent less time sedentary, compared to children in control schools (32.3% vs. 33.4% of registered time, P=0.03) and more time in MVPA (28.5% vs. 27.6%, P=0.05). Children in the intervention group spent more time in MVPA (37.2% vs. 34.9%, P=0.002) and less time sedentary (22.0% vs. 24.3%, P<0.001) during after school care time. Normal weight and overweight children in intervention schools spent more time in MVPA and less time sedentary during after school care time compared to children in the control schools. Overweight children in the intervention group spent more time in light intensity activity during evening time. There was a trend for less sedentary activities in overweight intervention children during evening time. The results were attenuated after adjustment for the sampling variation between schools.

    CONCLUSIONS: There were indications of differences between intervention and control groups in time spent sedentary and in MVPA among normal weight and overweight children. Although differences were not statistically significant after adjustment for the cluster effect, the present paper provides argument for school-based interventions in order to decrease sedentary behaviour and increase physical activity.

  • 430. Nybo, Lars
    et al.
    Nielsen, Bodil
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Moller, Kirsten
    Secher, Niels
    Neurohumoral responses during prolonged exercise in humans.2003In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 95, no 3, p. 1125-31Article in journal (Refereed)
    Abstract [en]

    This study examined neurohumoral alterations during prolonged exercise with and without hyperthermia. The cerebral oxygen-to-carbohydrate uptake ratio (O2/CHO = arteriovenous oxygen difference divided by arteriovenous glucose difference plus one-half lactate), the cerebral balances of dopamine, and the metabolic precursor of serotonin, tryptophan, were evaluated in eight endurance-trained subjects during exercise randomized to be with or without hyperthermia. The core temperature stabilized at 37.9 +/- 0.1 degrees C (mean +/- SE) in the control trial, whereas it increased to 39.7 +/- 0.2 degrees C in the hyperthermic trial, with a concomitant increase in perceived exertion (P < 0.05). At rest, the brain had a small release of tryptophan (arteriovenous difference of -1.2 +/- 0.3 micromol/l), whereas a net balance was obtained during the two exercise trials. Both the arterial and jugular venous dopamine levels became elevated during the hyperthermic trial, but the net release from the brain was unchanged. During exercise, the O2/CHO was similar across trials, but, during recovery from the hyperthermic trial, the ratio decreased to 3.8 +/- 0.3 (P < 0.05), whereas it returned to the baseline level of approximately 6 within 5 min after the control trial. The lowering of O2/CHO was established by an increased arteriovenous glucose difference (1.1 +/- 0.1 mmol/l during recovery from hyperthermia vs. 0.7 +/- 0.1 mmol/l in control; P < 0.05). The present findings indicate that the brain has an increased need for carbohydrates during recovery from strenuous exercise, whereas enhanced perception of effort as observed during exercise with hyperthermia was not related to alterations in the cerebral balances of dopamine or tryptophan.

  • 431.
    Oddsson, Kristjan
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Danielsson, Evelina
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH. Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Wahlgren, Lina
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Development of physical tests and ratings scales of perceived health in a project with supervised physical activity for elderly.2010Conference paper (Refereed)
    Abstract [en]

    Background: Valid and reliable field tests for measuring physical fitness and different health parameters is an important matter for evaluating effects of exercise interventions.

    Purpose: The aim was to study different test parameters such as aerobic capacity, strength, perceived health and life style habits, such as physical activity, in a physical activity intervention for elderly people.

    Method: 117 old-age pensioners (99 women and 18 men). Their mean age (yrs) and BMI (kg/m2 ) was 74 and 26 for the women and 73 and 25 for the men, respectively. Different aerobic, strength and balance tests were measured. Guided physical activity (nordic walking, strength training, aqua gymnastics), were given 45-60 min, 2 times/week for 8-12 weeks. Perceived exertion ratings during the exercises were moderate and/or strong.

    Results: Significant changes (p< 0,05) were seen between pre- and post tests regarding all physical tests except the balance test for men. Even the perceived physical and mental health significantly improved. The mean values for questions concerning self reported inactive/active life style, including sedentary time, were changed to a more active life style.

    Conclusion: 8-12 weeks of guided physical activity can improve several physiological parameters which are positively correlated to decreased risk of numerous diseases. More research is needed to develop reliable and valid field tests for physical capacity and different health parameters.

  • 432.
    Olsson, Gustav
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Ekblom Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology. Göteborgs Universitet.
    Is the relationship between self-perceived physical health and measured physical fitness robust over time and between genders?Manuscript (preprint) (Other academic)
  • 433.
    Olsson, Sven Johan Gustav
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Baksidan av myntet - inaktiviteten: Ny avhandling: Studies of physical activity in the Swedish population2016In: Idrottsmedicin, ISSN 2001-3302, Vol. 35, no 3, p. 27-29Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Sammanfattning av Olssons avhandling

  • 434.
    Olsson, Sven Johan Gustav
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Studies of physical activity in the Swedish population2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Cheap and effective tools for measuring patients’ physical activity (PA) level are needed. The first aim in this thesis was therefore to assess the validity of two PA -questions, and their three associated answer modes, that are used within the Swedish health care system. Sitting, light intensity PA (LIPA), and moderate and vigorous intensity PA (MVPA), are associated with health and longevity, but detailed population data assessed with objective methods is needed. The second aim was thus to assess the above with motion sensor technology, in a middle-aged Swedish sample. Low self-perceived health is a strong predictor of morbidity and mortality, but this association may vary over time with changes in the society and our lifestyle. The third aim was to assess secular trends in the interrelations between self-perceived health, physical fitness, and selected covariates. The effects of PA on prescription (PAP) on health-related quality of life (HRQoL) in overweight adults are unclear, thus the fourth aim was to explore this.

    Methods: All data was collected in the Swedish population. Data from the PA -questions and accelerometers, aerobic fitness, counter movement jump, and balance tests, blood samples, and self-rated general health were collected in 365 participants, 21–66 yrs. The PA pattern was assessed in 948 individuals, 50‒64 yrs, from the SCAPIS pilot study. Self-perceived physical health, and measured aerobic fitness, counter movement jump height, and balance, and demographic and lifestyle data, was assessed in three independent samples from 1990, 2000 and 2013, including 3564 adults, 20‒65 yrs. The effects of Swedish PAP on HRQoL was assessed in a randomized controlled trial including 101 men and women, 67‒68 yrs, that were inactive, overweight (BMI>25 kg/m2), and had a waist circumference ≥102 cm (men) or ≥88 cm (women), who were randomized to an intervention group or a control group. The 36-item Short Form Health Survey (SF-36) was used to assess HRQoL.

    Results: The multiple choice answer mode of the two PA -questions was found to have the strongest validity, compared with the two other (an open mode, and one where PA minutes is specified per weekday). The validity is in line with many other established PA-questionnaires, but the open mode has limitations. The assessment of PA pattern showed that 61% of motion sensor wear time represented sitting, 35% LIPA, and 4% MVPA. Only 7% of the sample met the PA recommendations. The odds for describing perceived health as good was found to increase by 5% per each increment of 1 ml/kg/min in VO2max. This was stable across genders and all three LIV-samples (i.e. over time). Waist circumference, chronic disease, sleep problems, and level of satisfaction with one’s life, were also important correlates. The Swedish PAP group improved significantly more, and more participants displayed clinically relevant improvements (OR 2.43), in mental aspects of HRQoL, compared to the controls. Physical aspects of HRQoL improved in the PAP group, but not in the control group.

    Conclusions: The multiple choice answer mode has the strongest validity and Open mode the weakest. The PA -questions may be used in populations, or in individuals to determine appropriateness for treatment. The questions’ advantages and limitations must be considered and further reliability and validity studies are needed. The results regarding sitting, LIPA, MVPA and fulfillment of PA recommendations, are of high clinical relevance. A great challenge remains to further implement methods to increase the level of PA in the Swedish population. Physical fitness is related to self-perceived health independently of changes in society and lifestyle over time, and simple questions may be useful for the clinical assessment of physical fitness. Swedish PAP has a positive effect on mental aspects of HRQoL, measured by the SF-36. This finding supports the clinical use of the Swedish PAP model.

  • 435.
    Olsson, Sven Johan Gustav
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Hemmingsson, Erik
    Karolinska Institutet.
    Hellénius, Mai-Lis
    Karolinska Institutet.
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Effects of the Swedish physical activity on prescription model on health-related quality of life in overweight older adults: a randomised controlled trial2015In: BMC Public Health, ISSN 1471-2458, E-ISSN 1471-2458, Vol. 15, article id 687Article in journal (Refereed)
    Abstract [en]

    Background

    The effects of physical activity on prescription (PAP) on health-related quality of life (HRQoL) in overweight adults are unclear. We therefore aimed to explore the effects of the Swedish PAP model on HRQoL in overweight older adults.

    Methods

    Participants were recruited from a cohort of men and women born between 1937 and 1938, and living in Stockholm County. Inclusion criteria were; insufficiently physically active, i.e. <30 min of at least moderate intensity physical activity (PA) per day; body mass index >25 kg/m 2 ; and waist circumference ≥102 cm (men) or ≥88 cm (women). Altogether, 101 individuals, aged 67 years, were randomly assigned to two parallel groups: intervention group (n = 47) receiving individualised PAP or control group (n = 54). The 36-item Short Form Health Survey (SF-36) was administered before and after the six months intervention. Main outcomes were the SF-36 physical component summary (PCS) and mental component summary (MCS) scores. Intention to treat analysis was utilised. Regression analysis was performed to assess whether changes in PA and body weight affected changes in HRQoL.

    Results

    At the six months follow-up, regarding the MCS score, the intervention group had improved significantly more (median: 4.4 [interquartile range (IQR): −2.4 to 23.3]) vs (median: 0.0 [IQR: −4.0 to 4.9]); p < 0.05) and a higher proportion of participants had attained relevant improvements (OR 2.43 (95 % CI 1.00–5.88) p < 0.05) compared to the controls. A within group improvement in the PCS score (median: 3.8 [IQR: −1.9 to 19.5] p < 0.05) was found in the intervention group. Changes in PA and body weight had a small, but significant, mediating effect on the changes in HRQoL.

    Conclusions

    PAP had a positive effect on HRQoL, measured by the SF-36 MCS, but no significant between group effect was seen on the PCS in overweight older adults. These effects were, to some extent, mediated by changes in PA and body weight. Our findings support clinical use of the Swedish PAP model.

    Trial registration

    ClinicalTrials.gov NCT02320760.

  • 436.
    Olsson, Sven Johan Gustav
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group. Department of Medicine, Unit of Cardiology, Karolinska University Hospital, Solna.
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Categorical answer modes provides superior validity to open answers when asking for level of physical activity: A cross-sectional study2016In: Scandinavian Journal of Public Health, ISSN 1403-4948, E-ISSN 1651-1905, Vol. 44, no 1, p. 70-76, article id 1403494815602830Article in journal (Refereed)
    Abstract [en]

    AIMS:

    Physical activity (PA) used as prevention and treatment of disease has created a need for effective tools for measuring patients' PA level. Our aim was therefore to assess the validity of two PA questions and their three associated answer modes.

    METHODS:

    Data on PA according to the PA questions and Actigraph GT3X+ accelerometers, aerobic fitness (VO2max), cardiovascular biomarkers, and self-rated general health were collected in 365 Swedish adults (21-66 years). The PA questions ask about weekly PA via categories (Categorical), an open-ended answer (Open), or specified day by day (Table).

    RESULTS:

    The Categorical mode, compared with the Open mode, correlated (Spearman's rho) significantly more strongly (p<0.05) with accelerometer PA (0.31 vs. 0.18) and VO2max (0.27 vs. 0.06), and the level of BMI (-0.20 vs. -0.02), waist circumference (-0.22 vs. -0.03), diastolic blood pressure (-0.16 vs. 0.08), glucose (-0.18 vs. 0.04), triglycerides (-0.31 vs. -0.07), and general health (0.35 vs. 0.19). The validity of the Categorical and Table modes were similar regarding VO2max and accelerometry, but the Categorical mode exhibited more significant and stronger correlations with cardiovascular biomarkers. The capacity of the PA questions to identify insufficiently physically active individuals ranged from 0.57 to 0.76 for sensitivity and from 0.47 to 0.79 for specificity.

    CONCLUSIONS:

    The Categorical mode exhibits the strongest validity and Open mode the weakest. The PA questions may be used on a population level, or as a tool for determining patents' appropriateness for treatment.

  • 437.
    Olsson, Sven Johan Gustav
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom-Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Kallings, Lena V
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology. Göteborg University.
    Association of perceived physical health and physical fitness in two Swedish national samples from 1990 and 2015.2018In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 28, no 2, p. 717-724Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Perceived health and physical fitness have been shown to correlate, and low levels of either variable increase the risk for future illness and mortality. However, risk factors and their interrelationship may vary between societies and over time. In this study, the associations of physical fitness and perceived health were therefore assessed in two Swedish national samples 25 years apart.

    METHODS: Perceived physical health, dichotomized as "good" or "bad", maximal oxygen uptake (VO2 max), counter movement jump (CMJ), balance (one-legged 60 second stance), and self-reported demographics and lifestyle were recorded in two cross-sectional samples (sample size, number of eligible participants) of Swedish adults, aged 20 - 65 years, in 1990 - 1991 (2203, 1365), and 2013 - 2015 (3357, 422).

    RESULTS: The odds for good perceived physical health increased by 5% per mL · kg(-1) · min(-1) of VO2 max, 3% per cm CMJ height, and decreased by 4% per 1 time of overbalancing, in both samples. Mutually adjusted regression models showed that perceived physical health was best predicted by VO2 max and chronic illness in 1990 and by age, BMI, and educational level in 2015.

    CONCLUSION: Perceived physical health was related to physical fitness in two samples of Swedish adults from 1990 and 2015. However, multivariate, and mutually adjusted models, indicate that the most important covariates of perceived physical health may have changed from VO2 max and chronic illness in 1990, to age, BMI, and educational level in 2015. This article is protected by copyright. All rights reserved.

  • 438. Onerup, Aron
    et al.
    Angerås, Ulf
    Bock, David
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Fagevik Olsén, Monika
    Gellerstedt, Martin
    Haglind, Eva
    Nilsson, Hanna
    Angenete, Eva
    The preoperative level of physical activity is associated to the postoperative recovery after elective cholecystectomy - A cohort study.2015In: International Journal of Surgery, ISSN 1743-9191, E-ISSN 1743-9159, Vol. 19, p. 35-41Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: There is an increasing interest in the role of preoperative physical activity for postoperative recovery. The effect of preoperative physical activity and recovery after cholecystectomy is unknown. The aim of this study was to evaluate the association of self-reported leisure-time preoperative physical activity with postoperative recovery and complications after elective cholecystectomy due to gallstone disease.

    METHODS: Prospective observational cohort study with 200 patients scheduled to undergo elective cholecystectomy. Level of self-assessed leisure-time physical activity was compared with recovery.

    RESULTS: Regular physical activity was associated with a higher degree of return to work within three weeks post-operatively (relative chance (RC) 1.26, p = 0.040); with a higher chance of leaving hospital within one day post-op (RC 1.23, p = 0.001), as well as with better mental recovery (RC 1.18, p = 0.049), compared to physically inactive. No statistically significant association was seen with return to work within one week or with self-assessed physical recovery.

    DISCUSSION: In clinical practice, evaluating the patients' level of physical activity is feasible, and may potentially be used to identify patients being more suitable for same-day surgery. Given the study design, the results from this study cannot prove causality.

    CONCLUSION: The present study shows that the preoperative leisure-time physical activity-level, is positively associated with less sick leave, a shorter hospital stay and with better mental recovery, three weeks post-elective cholecystectomy. We recommend assessing the physical activity-level preoperatively for prognostic reasons. If preoperative/postoperative physical training will increase recovery remains to be shown in a randomized controlled study.

  • 439. Ortenblad, Niels
    et al.
    Macdonald, Will A
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Glycolysis in contracting rat skeletal muscle is controlled by factors related to energy state.2009In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 420, no 2, p. 161-8Article in journal (Refereed)
    Abstract [en]

    The control of glycolysis in contracting muscle is not fully understood. The aim of the present study was to examine whether activation of glycolysis is mediated by factors related to the energy state or by a direct effect of Ca2+ on the regulating enzymes. Extensor digitorum longus muscles from rat were isolated, treated with cyanide to inhibit aerobic ATP production and stimulated (0.2 s trains every 4 s) until force was reduced to 70% of initial force (control muscle, referred to as Con). Muscles treated with BTS (N-benzyl-p-toluene sulfonamide), an inhibitor of cross-bridge cycling without affecting Ca2+ transients, were stimulated for an equal time period as Con. Energy utilization by the contractile apparatus (estimated from the observed relation between ATP utilization and force-time integral) was 60% of total. In BTS, the force-time integral and ATP utilization were only 38 and 58% of those in Con respectively. Glycolytic rate in BTS was only 51% of that in Con but the relative contribution of ATP derived from PCr (phosphocreatine) and glycolysis and the relation between muscle contents of PCr and Lac (lactate) were not different. Prolonged cyanide incubation of quiescent muscle (low Ca2+) did not change the relation between PCr and Lac. The reduced glycolytic rate in BTS despite maintained Ca2+ transients, and the unchanged PCr/Lac relation in the absence of Ca2+ transients, demonstrates that Ca2+ is not the main trigger of glycogenolysis. Instead the preserved relative contribution of energy delivered from PCr and glycolysis during both conditions suggests that the glycolytic rate is controlled by factors related to energy state.

  • 440.
    Ortenblad, Niels
    et al.
    Univ Southem Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, Odense, Denmark.;Univ British Columbia, Sch Kinesiol, Vancouver, BC, Canada..
    Nielsen, Joachim
    Univ Southem Denmark, SDU Muscle Res Cluster, Dept Sports Sci & Clin Biomech, Odense, Denmark..
    Boushel, Robert
    Univ British Columbia, Sch Kinesiol, Vancouver, BC, Canada..
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Saltin, Bengt
    Copenhagen Muscle Res Ctr, Copenhagen, Denmark..
    Holmberg, Hans-Christer
    Mid Sweden Univ, Swedish Winter Sports Res Ctr, Ostersund, Sweden.;UiT Arctic Univ Norway, Sch Sport Sci, Tromso, Norway..
    The Muscle Fiber Profiles, Mitochondrial Content, and Enzyme Activities of the Exceptionally Well-Trained Arm and Leg Muscles of Elite Cross-Country Skiers2018In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, article id 1031Article in journal (Refereed)
    Abstract [en]

    As one of the most physically demanding sports in the Olympic Games, cross-country skiing poses considerable challenges with respect to both force generation and endurance during the combined upper-and lower-body effort of varying intensity and duration. The isoforms of myosin in skeletal muscle have long been considered not only to define the contractile properties, but also to determine metabolic capacities. The current investigation was designed to explore the relationship between these isoforms and metabolic profiles in the arms (triceps brachii) and legs (vastus lateralis) as well as the range of training responses in the muscle fibers of elite cross-country skiers with equally and exceptionally well-trained upper and lower bodies. The proportion of myosin heavy chain (MHC)-1 was higher in the leg (58 +/- 2% [34-69%]) than arm (40 +/- 3% [24-57%]), although the mitochondrial volume percentages [8.6 +/- 1.6 (leg) and 9.0 +/- 2.0 (arm)], and average number of capillaries per fiber [5.8 +/- 0.8 (leg) and 6.3 +/- 0.3 (arm)] were the same. In these comparable highly trained leg and arm muscles, the maximal citrate synthase (CS) activity was the same. Still, 3-hydroxy-acyl-CoA-dehydrogenase (HAD) capacity was 52% higher (P < 0.05) in the leg compared to arm muscles, suggesting a relatively higher capacity for lipid oxidation in leg muscle, which cannot be explained by the different fiber type distributions. For both limbs combined, HAD activity was correlated with the content of MHC-1 (r(2) = 0.32, P = 0.011), whereas CS activity was not. Thus, in these highly trained cross-country skiers capillarization of and mitochondrial volume in type 2 fiber can be at least as high as in type 1 fibers, indicating a divergence between fiber type pattern and aerobic metabolic capacity. The considerable variability in oxidative metabolism with similar MHC profiles provides a new perspective on exercise training. Furthermore, the clear differences between equally well-trained arm and leg muscles regarding HAD activity cannot be explained by training status or MHC distribution, thereby indicating an intrinsic metabolic difference between the upper and lower body. Moreover, trained type 1 and type 2A muscle fibers exhibited similar aerobic capacity regardless of whether they were located in an arm or leg muscle.

  • 441. Palmefors, Henning
    et al.
    DuttaRoy, Smita
    Rundqvist, Bengt
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    The effect of physical activity or exercise on key biomarkers in atherosclerosis: a systematic review2014In: Atherosclerosis, ISSN 0021-9150, E-ISSN 1879-1484, Vol. 235, no 1, p. 150-61Article, review/survey (Refereed)
    Abstract [en]

    OBJECTIVE: This systematic review aimed to summarize published papers on the effect of physical activity (PA)/exercise on key atherosclerotic factors in patients with risk factors for or established cardiovascular disease (CVD).

    METHODS: Studies involving PA and cytokines, chemokines, adhesion molecules, CRP and angiogenic factors were searched for in Medline and Cochrane library. Original human studies of more than 2 weeks of PA intervention were included. Study quality was assessed according to the GRADE system of evidence.

    RESULTS: Twenty-eight papers fulfilled the inclusion criteria. PA decreases the cytokines, tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6), and interferon-y IFN-y (high, moderate and low evidence, respectively). The effect of PA on chemokines; stromal derived factor-1 (SDF-1), interleukin-8 (IL-8) (insufficient evidence) and monocyte chemoattractant protein-1 (MCP-1) (low evidence) was inconclusive. Aerobic exercise decreased the adhesion molecules, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) (moderate and high evidence, respectively), while effects of PA on E- and P-selectin were inconclusive. PA decreases C-reactive protein (CRP) (high evidence). The angiogenic actors, endothelial progenitor cells (EPCs) are increased (high evidence) and VEGF is decreased (moderate evidence) by PA. The effect of PA on these factors seems to depend on the type and duration of exercise intervention and patient factors, such as presence of ischemia.

    CONCLUSION: As presented in this review, there is a high level of evidence that physical activity positively affects key players in atherosclerosis development. These effects could partly explain the scientifically proven anti-atherogenic effects of PA, and do have important clinical implications.

  • 442.
    Pantzar, Alexandra
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Jonasson, Lars S.
    Umeå University.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Boraxbekk, Carl-Johan
    Umeå University.
    Ekblom, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control. Karolinska Institutet.
    Relationships Between Aerobic Fitness Levels and Cognitive Performance in Swedish Office Workers2018In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 9, article id 2612Article in journal (Refereed)
    Abstract [en]

    Objectives: Aerobic exercise influence cognition in elderly, children, and neuropsychiatric populations. Less is known about the influence of aerobic exercise in healthy samples (particularly working age), and of different fitness levels on cognition. Two hypotheses were posed: 1) low fitness levels, compared to moderate and high, will be related to poorer cognitive performance, and 2) breakpoints for the beneficial relationship between VO2 and cognition will be observed within the moderate-to-high fitness span. Design and Methods: The sample consisted of n=362 office workers. A submaximal cycle ergometer test estimated maximal oxygen consumption (VO2max, mL•kg-1•min-1). Based on estimated VO2max participants were split into tertiles; low (n=121), moderate (n=119), and high (n=122). A cognitive test battery (9 tests), assessed processing speed, working memory, executive functions and episodic memory. Results: Both hypotheses were confirmed. Groups of moderate (≈40) and high (≈49) fitness outperformed the group of low (≈31) fitness for inhibition and episodic recognition, whereas no significant differences between moderate and high fitness were observed (ANCOVAs). Breakpoints between benefits fromVO2max for inhibition and recognition were estimated to ≈44/43 mL•kg-1•min-1 (multivariate broken line regressions). Conclusions: Results suggest that it is conceivable to expect a beneficial relationship between VO2max and some cognitive domains up to a certain fitness level. In a sample of healthy office workers, this level was estimated to 44 mL•kg-1•min-1. This has implications on organizational and societal levels; where incentives to improve fitness levels from low to moderate could yield desirable cognitive and health benefits in adults.

  • 443. Patrik Johansson, H
    et al.
    Rossander-Hulthén, Lena
    Slinde, Frode
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Accelerometry combined with heart rate telemetry in the assessment of total energy expenditure.2006In: British Journal of Nutrition, ISSN 0007-1145, E-ISSN 1475-2662, Vol. 95, no 3, p. 631-9Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was: (1) to develop a new method for total energy expenditure (TEE) assessment, using accelerometry (ACC) and heart rate (HR) telemetry in combination; (2) to validate the new method against the criterion measure (DLW) and to compare with two of the most common methods, FLEX-HR and ACC alone. In the first part of the study VO(2), HR and ACC counts were measured in twenty-seven subjects during walking and running on a treadmill. Considering the advantages and disadvantages of the HR and ACC methods an analysis model was developed, using ACC at intensities of low and medium levels and HR at higher intensities. During periods of inactivity, RMR is used. A formula for determining TEE from ACC, HR and RMR was developed: TEE = 1.1x(EQ(HR) x TT(HR) + EQ(ACC1) x TT(ACC1) + EQ(ACC2) x TTACC2 + RMR x TT(RMR)). In the validation part of the study a sub-sample of eight subjects wore an accelerometer, HR was logged and TEE was measured for 14 d with the DLW method. Analysis of the Bland-Altman plots with 95 % CI indicates that there are no significant differences in TEE estimated with HR-ACC and ACC alone compared with TEE measured with DLW. It is concluded that the HR-ACC combination as well as ACC alone has potential as a method for assessment of TEE during free-living activities as compared with DLW.

  • 444.
    Petré, Henrik
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Löfving, Pontus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Psilander, Niklas
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    The Effect of Two Different Concurrent Training Programs on Strength and Power Gains in Highly-Trained Individuals.2018In: Journal of Sports Science and Medicine (JSSM), ISSN 1303-2968, Vol. 17, no 2, p. 167-173Article in journal (Refereed)
    Abstract [en]

    The effects of concurrent strength and endurance training have been well studied in untrained and moderately-trained individuals. However, studies examining these effects in individuals with a long history of resistance training (RT) are lacking. Additionally, few studies have examined how strength and power are affected when different types of endurance training are added to an RT protocol. The purpose of the present study was to compare the effects of concurrent training incorporating either low-volume, high-intensity interval training (HIIT, 8-24 Tabata intervals at ~150% of VO2max) or high-volume, medium-intensity continuous endurance training (CT, 40-80 min at 70% of VO2max), on the strength and power of highly-trained individuals. Sixteen highly-trained ice-hockey and rugby players were divided into two groups that underwent either CT (n = 8) or HIIT (n = 8) in parallel with RT (2-6 sets of heavy parallel squats, > 80% of 1RM) during a 6-week period (3 sessions/wk). Parallel squat performance improved after both RT + CT and RT + HIIT (12 ± 8% and 14 ± 10% respectively, p < 0.01), with no difference between the groups. However, aerobic power (VO2max) only improved after RT + HIIT (4 ± 3%, p < 0.01). We conclude that strength gains can be obtained after both RT + CT and RT + HIIT in athletes with a prior history of RT. This indicates that the volume and/or intensity of the endurance training does not influence the magnitude of strength improvements during short periods of concurrent training, at least for highly-trained individuals when the endurance training is performed after RT. However, since VO2max improved only after RT + HIIT and this is a time efficient protocol, we recommend this type of concurrent endurance training.

  • 445.
    Psilander, Niklas
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll. Karolinska institutet, Inst för fysiologi och farmakologi / Dept of Physiology and Pharmacology .
    The effect of different exercise regimens on mitochondrial biogenesis and performance2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Endurance training is a powerful tool to improve both health and performance. Physical activity is now recognized as an effective treatment and prevention therapy for a wide range of diseases. One of the most profound adaptations to endurance training is increased mitochondrial function and content within the exercising muscles. Mitochondrial quality and quantity are closely related to several of the positive health effects reported after training. High mitochondrial content strongly correlates with muscle oxidative capacity and endurance performance. Even though it is well known that endurance training increases mitochondrial content, it is unclear which type of training is the most efficient to promote mitochondrial biogenesis. Therefore, the basis for current exercise recommendations relative to mitochondrial biogenesis is poor or absent. Thus, the main objective of this thesis was to evaluate the effect of different training strategies on mitochondrial biogenesis.

    Recent developments in molecular methods have made it possible to study the initial adaptations to training through measurement of mRNA gene expression of exercise induced genes. One such gene is transcriptional coactivator peroxisome proliferator–activated receptor-γ coactivator-1α (PGC-1α). PGC-1α is a key regulator of mitochondrial biogenesis and the expression of PGC-1α can therefore be used as a marker of this process.

    The first four studies presented in this thesis are acute exercise studies where two different exercise models were compared using a cross-over design. Muscle biopsies were obtained pre and post exercise and analysed for gene expression and glycogen, apart from study II. The final study was a long-term training study where muscle biopsies were obtained before and after the training period and analysed for mitochondrial enzyme activities and protein content.

    Study I: The expression of PGC-1α and related genes were examined after 90 min of continuous and interval exercise in untrained subjects. The exercise protocols influenced the expression of genes involved in mitochondrial biogenesis and oxidative metabolism in a similar manner. Both interval and continuous exercise were potent training strategies for relatively sedentary individuals.

    Study II: The expression of PGC-1α and related genes were examined after low-volume sprint interval (SIT) and high-volume interval (IE) exercise in highly trained cyclists. SIT induced a similar increase in PGC-1α expression as IE despite a much lower time commitment and work completed. Sprint interval exercise might, therefore, be a time efficient training strategy for highly trained individuals.

    Study III: The expression of PGC-1α and related genes, as well as the activity of upstream proteins, were examined after concurrent (ER: cycling + leg press) and single-mode (E: cycling only) exercise in untrained subjects. PGC-1α expression doubled after ER compared with E. It was concluded that concurrent training might be beneficial for mitochondrial biogenesis in untrained individuals.

    Study IV: The expression of PGC-1α and related genes were examined after exercise performed with low (LG) and normal (NG) muscle glycogen in well-trained cyclists. PGC-1α expression increased approximately three times more after LG compared with NG. This finding suggested that low glycogen exercise is a potent inducer of mitochondrial biogenesis in well-trained individuals.

    Study V: Mitochondrial enzyme activity, protein content and endurance performance were examined after eight weeks of concurrent (ES: cycling + leg press) or single-mode (E: cycling only) training in cyclists. ES did not affect enzyme activity, protein content or endurance performance differently than E. The beneficial effect previously observed in untrained subjects did not translate to higher numbers of mitochondria in trained individuals.

    In three of the studies, I, III, and IV, both glycogen and PGC-1α expression were measured after exercise. These data were then pooled and examined. The highest PGC-1α mRNA expression levels were identified when glycogen levels were low, and vice versa. This suggests that low glycogen might play an important role in the regulation of mitochondrial biogenesis also during interval and concurrent strength and endurance exercise.

    In conclusion, key markers of mitochondrial biogenesis can be effectively up-regulated by interval, concurrent and low glycogen exercise. A possible explanation for this might be that though the exercise protocols are quite divergent in nature, they all have a pronounced effect on muscle glycogen and/or perturbation in energetic stress.

  • 446.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Eftestøl, Einar
    University of Oslo, Norway.
    Cumming, Kristoffer Toldnes
    Norwegian School of Sport Sciences, Norway.
    Juvkam, Inga
    University of Oslo, Norway.
    Ekblom, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Sunding, Kerstin
    Karolinska Institutet.
    Wernbom, Mathias
    Göteborg University.
    Holmberg, Hans-Christer
    Mid Sweden University.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Bruusgaard, Jo C
    University of Oslo, Norway..
    Raastad, Truls
    Norwegian School of Sport Sciences, Norway.
    Gundersen, Kristian
    University of Oslo, Norway..
    Effects of training, detraining, and retraining on strength, hypertrophy, and myonuclear number in human skeletal muscle2019In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 126, no 6, p. 1636-1645Article in journal (Refereed)
    Abstract [en]

    Previously trained mouse muscles acquire strength and volume faster than naïve muscles; it has been suggested that this is related to increased myonuclear density. The present study aimed to determine whether a previously strength-trained leg (mem-leg) would respond better to a period of strength training than a previously untrained leg (con-leg). Nine men and 10 women performed unilateral strength training (T1) for 10 weeks, followed by 20 weeks of detraining (DT) and a 5-week bilateral retraining period (T2). Muscle biopsies were taken before and after each training period and analyzed for myonuclear number, fiber volume, and cross-sectional area (CSA). Ultrasound and one repetition of maximum leg extension were performed to determine muscle thickness (MT) and strength. CSA (~17%), MT (~10%), and strength (~20%) increased during T1 in the mem-leg. However, the myonuclear number and fiber volume did not change. MT and CSA returned to baseline values during DT, but strength remained elevated (~60%), supporting previous findings of a long-lasting motor learning effect. MT and strength increased similarly in the mem-leg and con-leg during T2, whereas CSA, fiber volume, and myonuclear number remained unaffected. In conclusion, training response during T2 did not differ between the mem-leg and con-leg. However, this does not discount the existence of human muscle memory since no increase in the number of myonuclei was detected during T1 and no clear detraining effect was observed for cell size during DT; thus, the present data did not allow for a rigorous test of the muscle memory hypothesis.

  • 447.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Frank, Per
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Adding strength to endurance training does not enhance aerobic capacity in cyclists2015In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 25, no 4, p. e353-e359Article in journal (Refereed)
    Abstract [en]

    The molecular signaling of mitochondrial biogenesis is enhanced when resistance exercise is added to a bout of endurance exercise. The purpose of the present study was to examine if this mode of concurrent training translates into increased mitochondrial content and improved endurance performance. Moderately trained cyclists performed 8 weeks (two sessions per week) of endurance training only (E, n = 10; 60-min cycling) or endurance training followed by strength training (ES, n = 9; 60-min cycling + leg press). Muscle biopsies were obtained before and after the training period and analyzed for enzyme activities and protein content. Only the ES group increased in leg strength (+19%, P < 0.01), sprint peak power (+5%, P < 0.05), and short-term endurance (+9%, P < 0.01). In contrast, only the E group increased in muscle citrate synthase activity (+11%, P = 0.06), lactate threshold intensity (+3%, P < 0.05), and long-term endurance performance (+4%, P < 0.05). Content of mitochondrial proteins and cycling economy was not affected by training. Contrary to our hypothesis, the results demonstrate that concurrent training does not enhance muscle aerobic capacity and endurance performance in cyclists.

  • 448.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Frank, Per
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Exercise with low glycogen increases PGC-1α gene expression in human skeletal muscle.2013In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 113, no 4, p. 951-963Article in journal (Refereed)
    Abstract [en]

    Recent studies suggest that carbohydrate restriction can improve the training-induced adaptation of muscle oxidative capacity. However, the importance of low muscle glycogen on the molecular signaling of mitochondrial biogenesis remains unclear. Here, we compare the effects of exercise with low (LG) and normal (NG) glycogen on different molecular factors involved in the regulation of mitochondrial biogenesis. Ten highly trained cyclists (VO(2max) 65 ± 1 ml/kg/min, W (max) 387 ± 8 W) exercised for 60 min at approximately 64 % VO(2max) with either low [166 ± 21 mmol/kg dry weight (dw)] or normal (478 ± 33 mmol/kg dw) muscle glycogen levels achieved by prior exercise/diet intervention. Muscle biopsies were taken before, and 3 h after, exercise. The mRNA of peroxisome proliferator-activated receptor-γ coactivator-1 was enhanced to a greater extent when exercise was performed with low compared with normal glycogen levels (8.1-fold vs. 2.5-fold increase). Cytochrome c oxidase subunit I and pyruvate dehydrogenase kinase isozyme 4 mRNA were increased after LG (1.3- and 114-fold increase, respectively), but not after NG. Phosphorylation of AMP-activated protein kinase, p38 mitogen-activated protein kinases and acetyl-CoA carboxylase was not changed 3 h post-exercise. Mitochondrial reactive oxygen species production and glutathione oxidative status tended to be reduced 3 h post-exercise. We conclude that exercise with low glycogen levels amplifies the expression of the major genetic marker for mitochondrial biogenesis in highly trained cyclists. The results suggest that low glycogen exercise may be beneficial for improving muscle oxidative capacity.

  • 449.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Petré, Henrik
    Swedish School of Sport and Health Sciences, GIH.
    Löfving, Pontus
    Swedish School of Sport and Health Sciences, GIH.
    Överdriven oro för kombinationsträning2015In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, no 1, p. 8-13Article in journal (Other academic)
    Abstract [sv]

    Många som vill öka sin muskelmassa och styrka undviker uthållighetsträning. En vanlig åsikt är nämligen att man inte bör kombinera styrke ochuthållighetsträning. Den uppfattningen har däremot inget stöd i den senaste forskningen.

  • 450.
    Psilander, Niklas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Nya forskningsrön kan ge bättre träningsmetoder2013In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 22, no 1, p. 41-44Article in journal (Other academic)
    Abstract [sv]

    Det finns många uppfattningar om hur man bäst förbättrar konditionen. Ofta förlitar idrottare sig mer på beprövad erfarenhet än på vetenskapen. Men under de senaste åren har idrottsforskningen, med hjälp av molekylärbiologisk teknik, gjort framsteg i hur man kan effektivisera sin träning genom kosten och sättet att träna.

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