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  • 51.
    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: Implications for Diet and Behavior2011In: Handbook of Behavior, Food and Nutrition / [ed] V.R. Preedy et al., Springer Science + Business Media , 2011, p. 865-877Chapter in book (Other academic)
  • 52.
    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.
    Fysiologisk forskning åren 1997-20132014In: Från Kungl. Gymnastiska Centralinstitutet till Gymnastik- och idrottshögskolan: en betraktelse av de senaste 25 åren som del av en 200-årig historia / [ed] Suzanne Lundvall, Stockholm: Gymnastik- och idrottshögskolan, GIH , 2014, p. 200-206Chapter in book (Other (popular science, discussion, etc.))
  • 53.
    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.
    Maximera träningen med fokus på kosten2018In: Idrottsmedicin, ISSN 2001-3302, Vol. 37, no 3, p. 6-7Article in journal (Other academic)
    Abstract [sv]

    Med fokus på kosten kan idrottare maximera träningens effekter. Genom att träna med låga glykogendepåer kan den aeroba prestationsförmågan öka och intag av essentiella aminosyror i samband med styrketräning kan stimulera tillväxt av muskelmassa.

  • 54.
    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.
    Utilisation of different energy sources during exercise and nutritional strategies for effective recovery2014In: Women and sport, Stockholm: SISU idrottsböcker , 2014Chapter in book (Other academic)
    Abstract [en]

    In this text, we will examine how the body uses the nutrients in food to produce energy during exercise, and whether these processes differ between the sexes. If they do, does this mean that the nutritional requirements should be different for men and women? We will also present current knowledge on the effects of nutrition on recovery after physical activity, a topic that has attracted much interest in the sports world. finally, we will briefl y discuss the nutritional requirements of physically active women and the common nutritional problems they encounter.

  • 55.
    Blomstrand, Eva
    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.
    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.
    Det viktigaste du behöver veta om protein och träning2018In: Idrottsforskning.se, ISSN 2002-3944, article id 30 majArticle in journal (Other (popular science, discussion, etc.))
  • 56.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Celsing, F
    Newsholme, E A
    Changes in plasma concentrations of aromatic and branched-chain amino acids during sustained exercise in man and their possible role in fatigue.1988In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 133, no 1, p. 115-21Article in journal (Refereed)
    Abstract [en]

    The plasma concentrations of branched-chain and aromatic amino acids have been measured in two different types of sustained dynamic exercise. Twenty-two subjects participated in the 1986 Stockholm Marathon and eight subjects took part in an army training programme of approximately 1.5-h duration. Both types of exercise caused a significant decrease in the plasma concentration of branched-chain amino acids, while there was no change in the concentration of total (free plus bound to albumin) tryptophan. The plasma concentration of free tryptophan, which was measured in the marathon runners, was found to increase 2.4-fold during the race. This increase is probably caused by a pronounced elevation in the concentration of plasma free fatty acids during exercise, since these are known to displace tryptophan from albumin. The observed increase in plasma free tryptophan concentration, together with the decrease in plasma concentration of branched-chain amino acids, gives rise to a marked increase in the plasma concentration ratio of free tryptophan/branched-chain amino acids. This should lead to an increase in the rate of transport of tryptophan across the blood-brain barrier and hence to an increase in the rate of synthesis of 5-hydroxytryptamine (5-HT) in the brain. An elevated concentration of 5-HT in specific areas of the brain may be responsible, at least in part, for the development of physical, and/or mental fatigue during prolonged exercise.

  • 57.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Ek, Sonja
    Newsholme, Eric A
    Influence of ingesting a solution of branched-chain amino acids on plasma and muscle concentrations of amino acids during prolonged submaximal exercise.1996In: Nutrition (Burbank, Los Angeles County, Calif.), ISSN 0899-9007, E-ISSN 1873-1244, Vol. 12, no 7-8, p. 485-90Article in journal (Refereed)
    Abstract [en]

    On two occasions, seven male endurance-trained cyclists performed sustained exhaustive exercise with reduced muscle glycogen stores. During exercise, the subjects were supplied in random order with an aqueous solution of branched-chain amino acids (BCAA) or flavored water (placebo). Ingestion of BCAA caused the concentration of these amino acids to increase by 135% in the plasma and by 57% in muscle tissue during exercise, whereas in the placebo trial there was no change or a slight decrease in the concentration in plasma and a decrease of 18% in the muscle. The plasma concentration of alanine increased by 48% during exercise when BCAA were ingested, and the increase in the muscle concentration of alanine during exercise was larger (70% versus 31% in the placebo trial), suggesting an increased rate of alanine production. Also, the plasma concentration of arginine increased by 14% during exercise when BCAA were ingested, whereas there was no change during exercise in the placebo trial. There was a smaller decrease in the muscle glutamate concentration during exercise in the BCAA trial (32% versus 47% in the placebo trial; p < 0.05), but, for the remaining amino acids, there was no difference between the BCAA and placebo trials. There was a significant decrease in the muscle glycogen concentration during exercise in the placebo trial, whereas only a small decrease was found in the BCAA trial (28 and 9 mmol/kg wet wt [p < 0.05] in the placebo and BCAA trial, respectively). This might indicate that an increased supply of BCAA has a sparing effect on muscle glycogen degradation during exercise.

  • 58.
    Blomstrand, Eva
    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.
    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.
    Hedman, Rune
    Schantz, Peter
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, The Research Unit for Movement, Health and Environment.
    Irma Åstrand: Nekrolog2016Other (Other (popular science, discussion, etc.))
  • 59.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Eliasson, Jörgen
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Karlsson, Håkan K R
    Köhnke, Rickard
    Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise2006In: Journal of Nutrition, ISSN 0022-3166, E-ISSN 1541-6100, Vol. 136, no 1 Suppl, p. 269S-273SArticle in journal (Refereed)
  • 60.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Essén-Gustavsson, B
    Influence of reduced muscle temperature on metabolism in type I and type II human muscle fibres during intensive exercise.1987In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 131, no 4, p. 569-74Article in journal (Refereed)
    Abstract [en]

    Six male subjects performed intensive cycle exercise to exhaustion after cooling their legs in water at 10-12 degrees C (muscle temperature (Tm) 28 +/- 2.6 degrees C, mean +/- SD). Exercise at exactly the same rate and duration (370 +/- 34 W, 1.5 +/- 0.2 min) was then repeated by each subject 2-5 weeks later at normal Tm (35 +/- 1.0 degrees C). Muscle biopsies were taken from the vastus lateralis muscle at rest and after exercise. The muscle tissue was freeze-dried and fragments of single fibres were dissected out. The fibres were classified and pooled into groups of type I and type II. Analyses of glycogen, glucose 6-phosphate, lactate and phosphagens were performed on pools of type-identified fibres. After exercise at reduced Tm, all subjects had higher concentrations of glucose 6-phosphate and lactate in both type I and type II fibres, and in most subjects the concentrations of ATP and phosphocreatine were lower as compared with the findings after exercise at normal Tm. During exercise the glycogen content of both fibre types decreased to a greater extent at reduced than at normal Tm in most subjects. The results suggest that during intensive dynamic exercise at reduced Tm there is a higher degree of glycolysis from glycogen in the muscle than in the normal situation. In some subjects the cause of fatigue may be related to a more rapid accumulation of lactate in the cold muscle, while in others fatigue may be related to alternative factors, e.g. low levels of ATP and phosphocreatine.

  • 61.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Essén-Gustavsson, Birgitta
    Changes in amino acid concentration in plasma and type I and type II fibres during resistance exercise and recovery in human subjects.2009In: Amino Acids, ISSN 0939-4451, E-ISSN 1438-2199, Vol. 37, no 4, p. 629-36Article in journal (Refereed)
    Abstract [en]

    Eight male subjects performed leg press exercise, 4 x 10 repetitions at 80% of their maximum. Venous blood samples were taken before, during exercise and repeatedly during 2 h of recovery. From four subjects, biopsies were taken from the vastus lateralis muscle prior to, immediately after and following one and 2 h of recovery. Samples were freeze-dried, individual muscle fibres were dissected out and identified as type I or type II. Resistance exercise led to pronounced reductions in the glutamate concentration in both type I (32%) and type II fibres (70%). Alanine concentration was elevated 60-75% in both fibre types and 29% in plasma. Glutamine concentration remained unchanged after exercise; although 2 h later the concentrations in both types of fibres were reduced 30-35%. Two hours after exercise, the plasma levels of glutamate and six of the essential amino acids, including the branched-chain amino acids were reduced 5-30%. The data suggest that glutamate acts as an important intermediate in muscle energy metabolism during resistance exercise, especially in type II fibres.

  • 62.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Hassmén, Peter
    Ek, S
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Newsholme, E A
    Influence of ingesting a solution of branched-chain amino acids on perceived exertion during exercise.1997In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 159, no 1, p. 41-9Article in journal (Refereed)
    Abstract [en]

    On two occasions, seven male endurance-trained cyclists performed exhaustive exercise on a cycle ergometer in the morning after they had performed a bout of exercise the preceding evening in an attempt to lower the muscle glycogen stores. The subjects exercised at a work rate corresponding to approximately 70% of their maximal oxygen uptake for 60 min, followed by another 20 min of maximal exercise. During exercise the subjects were given either a solution of branched-chain amino acids (BCAAs) or flavoured water (placebo). Every 10 min during exercise the subjects rated their perceived exertion and mental fatigue on two different Borg scales. During the 60 min exercise at a given work rate the subjects ratings of perceived exertion when they were given BCAAs were 7% lower, and their ratings of mental fatigue were 15% lower than when they were given placebo. In addition, the performance in the colour task of Stroops Colour Word Test performed after exercise was improved when BCAAs had been ingested during exercise, compared with the results from the placebo trial. There was no difference in the physical performance between the two trials measured as the amount of work done during the last 20 min of exercise when the subjects performed at their maximum. The plasma concentration ratio of free tryptophan/BCAAs, which increased by 45% during exercise and by 150% 5 min after exercise in the placebo trial, remained unchanged or even decreased when BCAAs were ingested.

  • 63.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Krustrup, Peter
    Søndergaard, Hans
    Rådegran, Göran
    Calbet, José A L
    Saltin, Bengt
    Exercise training induces similar elevations in the activity of oxoglutarate dehydrogenase and peak oxygen uptake in the human quadriceps muscle.2011In: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 462, no 2, p. 257-65Article in journal (Refereed)
    Abstract [en]

    During exercise involving a small muscle mass, peak oxygen uptake is thought to be limited by peripheral factors, such as the degree of oxygen extraction from the blood and/or mitochondrial oxidative capacity. Previously, the maximal activity of the Krebs cycle enzyme oxoglutarate dehydrogenase has been shown to provide a quantitative measure of maximal oxidative metabolism, but it is not known whether the increase in this activity after a period of training reflects the elevation in peak oxygen consumption. Fourteen subjects performed one-legged knee extension exercise for 5-7 weeks, while the other leg remained untrained. Thereafter, the peak oxygen uptake by the quadriceps muscle was determined for both legs, and muscle biopsies were taken for assays of maximal enzyme activities (at 25°C). The peak oxygen uptake was 26% higher in the trained than in the untrained muscle (395 vs. 315 ml min(-1) kg(-1), respectively; P<0.01). The maximal activities of the Krebs cycle enzymes in the trained and untrained muscle were as follows: citrate synthase, 22.4 vs. 18.2 μmol min(-1) g(-1) (23%, P<0.05); oxoglutarate dehydrogenase, 1.88 vs. 1.54 μmol min(-1) g(-1) (22%, P<0.05); and succinate dehydrogenase, 3.88 vs. 3.28 μmol min(-1) g(-1) (18%, P<0.05). The difference between the trained and untrained muscles with respect to peak oxygen uptake (80 ml min(-1) kg(-1)) corresponded to a flux through the Krebs cycle of 1.05 μmol min(-1) g(-1), and the corresponding difference in oxoglutarate dehydrogenase activity (at 38°C) was 0.83 μmol min(-1) g(-1). These parallel increases suggest that there is no excess mitochondrial capacity during maximal exercise with a small muscle mass.

  • 64.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Møller, K
    Secher, N H
    Nybo, L
    Effect of carbohydrate ingestion on brain exchange of amino acids during sustained exercise in human subjects.2005In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 185, no 3, p. 203-9Article in journal (Refereed)
    Abstract [en]

    AIM: This study investigated the effect of prolonged exercise with and without carbohydrate intake on the brain exchange of amino acids, especially focussing on tryptophan and branched-chain amino acids (BCAA). METHODS: Five male subjects exercised for 3 h on a cycle ergometer at 200 +/- 7 W on two occasions; either supplemented with a 6% carbohydrate solution or with flavoured water (placebo). Catheters were inserted into the right internal jugular vein and the radial artery of the non-dominant arm. The brain exchange of amino acids during exercise was calculated from the arterial-jugular venous concentration difference multiplied by plasma flow. RESULTS: About 106 micromol (22 mg) of tryptophan was taken up by the brain during exercise in the placebo trial, whereas no significant uptake was observed in the carbohydrate trial. In accordance, the arterial concentration of free tryptophan increased from 12 +/- 1 to 20 +/- 2 micromol L(-1) during the placebo trial and was significantly higher compared with the glucose trial (14 +/- 1 micromol L(-1) at the end of exercise). Also, the arterial concentration of total tryptophan (free and albumin-bound) increased during the first 30 min of exercise in both trials, but returned to the basal level at 180 min of exercise. In both trials, BCAA were taken up by the brain while glutamine was released. CONCLUSION: The present data show that both tryptophan and BCAA are taken up by the brain during prolonged exercise, and we suggest that the cerebral uptake of tryptophan may relate to increased synthesis of serotonin (5-HT) in the brain.

  • 65.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Rådegran, Göran
    Saltin, Bengt
    Maximum rate of oxygen uptake by human skeletal muscle in relation to maximal activities of enzymes in the Krebs cycle.1997In: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 501 ( Pt 2), p. 455-60Article in journal (Refereed)
    Abstract [en]

    1. Ten subjects performed incremental exercise up to their maximum work rate with the knee extensors of one leg. Measurements of leg blood flow and femoral arteriovenous differences of oxygen were made in order to be able to calculate oxygen uptake of the leg. 2. The volume of the quadriceps muscle was determined from twenty-one to twenty-five computer tomography section images taken from the patella to the anterior inferior iliac spine of each subject. 3. The maximal activities of three enzymes in the Krebs cycle, citrate synthase, oxoglutarate dehydrogenase and succinate dehydrogenase, were measured in biopsy samples taken from the vastus lateralis muscle. 4. The average rate of oxygen uptake over the quadriceps muscle at maximal work, 353 ml min-1 kg-1, corresponded to a Krebs cycle rate of 4.6 mumol min-1 g-1. This was similar to the maximal activity of oxoglutarate dehydrogenase (5.1 mumol min-1 g-1), whereas the activities of succinate dehydrogenase and citrate synthase averaged 7.2 and 48.0 mumol min-1 g-1, respectively. 5. It is suggested that of these enzymes, only the maximum activity of oxoglutarate dehydrogenase can provide a quantitative measure of the capacity of oxidative metabolism, and it appears that the enzyme is fully activated during one-legged knee extension exercise at the maximal work rate.

  • 66.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Saltin, Bengt
    BCAA intake affects protein metabolism in muscle after but not during exercise in humans.2001In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 281, no 2, p. E365-74Article in journal (Refereed)
    Abstract [en]

    Branched-chain amino acids (BCAA) or a placebo was given to seven subjects during 1 h of ergometer cycle exercise and a 2-h recovery period. Intake of BCAA did not influence the rate of exchange of the aromatic amino acids, tyrosine and phenylalanine, in the legs during exercise or the increase in their concentration in muscle. The increase was approximately 30% in both conditions. On the other hand, in the recovery period after exercise, a faster decrease in the muscle concentration of aromatic amino acids was found in the BCAA experiment (46% compared with 25% in the placebo condition). There was also a tendency to a smaller release (an average of 32%) of these amino acids from the legs during the 2-h recovery. The results suggest that BCAA have a protein-sparing effect during the recovery after exercise, either that protein synthesis has been stimulated and/or protein degradation has decreased, but the data during exercise are too variable to make any conclusions about the effects during exercise. The effect in the recovery period does not seem to be mediated by insulin.

  • 67.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Saltin, Bengt
    Effect of muscle glycogen on glucose, lactate and amino acid metabolism during exercise and recovery in human subjects.1999In: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 514 ( Pt 1), p. 293-302Article in journal (Refereed)
    Abstract [en]

    1. Eight subjects performed two-legged exercise, one leg with low and the other with normal muscle glycogen content. The purpose was to study the effect of low initial muscle glycogen content on the metabolic response during 1 h of exercise and 2 h of recovery. This model allows direct comparison of net fluxes of substrates and metabolites over the exercising legs receiving the same arterial inflow. 2. Muscle glycogen breakdown during exercise was 60% lower in the leg with a reduced pre-exercise glycogen concentration and the rate of glucose uptake during exercise was 30% higher. 3. The amount of pyruvate that was oxidized during exercise was calculated to be approximately 450 mmol in the low-glycogen leg and 750 mmol in the normal-glycogen leg, which suggests more fat and amino acid oxidation in the low-glycogen leg. 4. During exercise, there was a significant release of amino acids not metabolized in the muscle, e. g. tyrosine and phenylalanine, only from the low-glycogen leg, suggesting an increased rate of net protein degradation in this leg. 5. The release of tyrosine and phenylalanine from the low-glycogen leg during the exercise period and the change in their muscle concentrations yield a net tyrosine and phenylalanine production rate of 1.4 and 1.5 mmol h-1, respectively. The net rate of protein degradation was then calculated to be 7-12 g h-1. 6. The results suggest that the observed differences in metabolism between the low-glycogen and the normal-glycogen leg are induced by the glycogen level per se, since the legs received the same arterial supply of hormones and substrates.

  • 68.
    Blomstrand, Eva
    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.
    Schantz, Peter
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, The Research Unit for Movement, Health and Environment.
    Berit Sjöberg: 1939-20182019Other (Other (popular science, discussion, etc.))
  • 69. Blücher, Gösta
    et al.
    Edmar, Désirée
    Schantz, Peter
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, The Research Unit for Movement, Health and Environment.
    Eva Nordenson: nekrolog2014Other (Other (popular science, discussion, etc.))
  • 70.
    Bojsen-Møller, Emil
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Boraxbekk, Carl-Johan
    Copenhagen University Hospital, Hvidovre, Denmark.
    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.
    Blom, Victoria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Sport Psychology research group.
    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 Physical Activity, Sedentary Behaviour and Cognitive Functions in Office Workers.2019In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 16, no 23, article id E4721Article in journal (Refereed)
    Abstract [en]

    Increasing evidence from animal experiments suggests that physical activity (PA) promotes neuroplasticity and learning. For humans, most research on the relationship between PA, sedentary behaviour (SB), and cognitive function has relied on self-reported measures of behaviour. Office work is characterised by high durations of SB combined with high work demands. While previous studies have shown that fitter office workers outperform their less fit colleagues in cognitive tests, the importance of PA and SB remains unknown. This study investigated associations between objectively measured PA and SB, using hip-worn accelerometers, and cognitive functions in 334 office workers. Time spent in moderate-to-vigorous PA (MVPA) was not associated with any cognitive outcome. However, time spent in SB tended to be positively associated with words recalled in free recall (β = 0.125). For the least fit participants, the average length of MVPA bouts was favourably related to Stroop performance (β = -0.211), while for the fitter individuals, a longer average length of MVPA bouts was related to worse recognition (β = -0.216). While our findings indicate that the length of MVPA bouts was associated with better Stroop performance in the least fit participants, our findings do not support the notion that more time spent in MVPA or less time in SB is associated with better cognitive function.

  • 71.
    Bolam, Kate A.
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Skinner, T L
    Sax, A T
    Adlard, K N
    Taaffe, D R
    A Comparison of Bone Mineral Density in Amateur Male Boxers and Active Non-boxers.2016In: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 37, no 9, p. 694-699Article in journal (Refereed)
    Abstract [en]

    To examine the site-specific osteogenic effect of upper limb impact-loading activity we compared the forearm and arm bone mineral density (BMD) of male boxers to that of active controls. A cross-sectional study was performed with 30 amateur male boxers (aged 18-44 years) and 32 age-matched, non-boxing, active controls. Participants had their regional and whole body BMD and bone mineral content (BMC) assessed by dual-energy X-ray absorptiometry. Hand grip strength, testosterone, oestradiol, sex hormone-binding globulin, vitamin D, lean and fat mass, and past and current physical activity were also assessed. Forearm and arm BMD were 1.5-2.2% higher in boxers than the control group although this was not statistically significant (p>0.05), with no significant difference for BMC (p>0.05). There were no differences between groups for spine, hip, or whole body BMD or BMC, or for body composition or hormone status. Within the arms, lean mass was associated with BMD and BMC in both boxers and the control group (BMD, r=0.60-0.76, p<0.001; BMC, r=0.67-0.82, p<0.001). There were no significant differences between amateur boxers and the control group for upper limb BMD and BMC. However, muscle mass appears to be particularly important to bone health of the upper limbs.

  • 72.
    Bolam, Kate A
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Skinner, Tina L
    Jenkins, David G
    Galvão, Daniel A
    Taaffe, Dennis R
    The Osteogenic Effect of Impact-Loading and Resistance Exercise on Bone Mineral Density in Middle-Aged and Older Men: A Pilot Study.2016In: Gerontology, ISSN 0304-324X, E-ISSN 1423-0003, Vol. 62, no 1, p. 22-32Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Regular exercise has been recommended as a potential strategy to counteract the age-related bone loss experienced by men; however, the optimal exercise prescription is not known.

    OBJECTIVE: To perform a pilot study to examine the osteogenic effect, safety and feasibility of a combined program of upper body resistance exercise and two doses of impact-loading exercise on bone mineral density (BMD) of middle-aged and older men.

    METHODS: Forty-two community-dwelling men aged 50-74 years were randomly assigned to either an exercise program of combined upper body resistance exercise and either high-dose impact-loading (HI; 80 jumps per session) or moderate-dose impact-loading (MOD; 40 jumps per session) or a control (CON) group. The 9-month intervention involved 4 sessions each week: 2 supervised clinic-based and 2 home-based. BMD of the lumbar spine, femoral neck, total hip, trochanter and whole body as well as lean and fat mass were assessed at baseline and 9 months by dual-energy X-ray absorptiometry. Bone turnover markers, hormone levels, physical function and muscle strength were also assessed.

    RESULTS: Following 9 months of training, significant differences in BMD among groups were found at the total hip (p = 0.010) and trochanter (p = 0.047) with BMD in the MOD group decreasing relative to the HI group. Although not significant, the HI group consistently preserved BMD, whereas BMD of the MOD and CON groups declined at the hip sites. Mean change for all groups at all skeletal sites was approximately within ±1%. There was no change in bone turnover markers. There were no adverse events as a result of the intervention; however, overall attendance for the HI and MOD groups was 53% (clinic: 68%, home: 38%) and 65% (clinic: 74%, home: 55%), respectively.

    CONCLUSIONS: This study indicates that while impact-loading exercise can be safely undertaken in middle-aged and older men, the current combined program did not elicit significant improvements in BMD. © 2015 S. Karger AG, Basel.

  • 73.
    Bolam, Kate
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Hagströmer, Maria
    Karolinska institutet.
    Hur finner vi de fysiskt inaktiva?2016In: Idrottsmedicin, ISSN 2001-3302, Vol. 35, no 3, p. 8-11Article in journal (Other academic)
  • 74.
    Borgenvik, 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.
    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.
    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.
    Supplementation with BCAA Reduces MAFbx Expression and Phenylalanine Concentration in Rested and Exercised Human Muscle2011In: Medicine & Science in Sports & Exercise, 2011, Vol. 43, no 5, p. 419-419Conference paper (Refereed)
  • 75.
    Borgenvik, 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.
    Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle.2012In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 302, no 5, p. E510-21Article in journal (Refereed)
    Abstract [en]

    Resistance exercise and amino acids are two major factors that influence muscle protein turnover. Here, we examined the effects of resistance exercise and branched-chain amino acids (BCAA), individually and in combination, on the expression of anabolic and catabolic genes in human skeletal muscle. Seven subjects performed two sessions of unilateral leg press exercise with randomized supplementation with BCAA or flavored water. Biopsies were collected from the vastus lateralis muscle of both the resting and exercising legs before and repeatedly after exercise to determine levels of mRNA, protein phosphorylation, and amino acid concentrations. Intake of BCAA reduced (P < 0.05) MAFbx mRNA by 30 and 50% in the resting and exercising legs, respectively. The level of MuRF-1 mRNA was elevated (P < 0.05) in the exercising leg two- and threefold under the placebo and BCAA conditions, respectively, whereas MuRF-1 total protein increased by 20% (P < 0.05) only in the placebo condition. Phosphorylation of p70(S6k) increased to a larger extent (∼2-fold; P < 0.05) in the early recovery period with BCAA supplementation, whereas the expression of genes regulating mTOR activity was not influenced by BCAA. Muscle levels of phenylalanine and tyrosine were reduced (13-17%) throughout recovery (P < 0.05) in the placebo condition and to a greater extent (32-43%; P < 0.05) following BCAA supplementation in both resting and exercising muscle. In conclusion, BCAA ingestion reduced MAFbx mRNA and prevented the exercise-induced increase in MuRF-1 total protein in both resting and exercising leg. Further-more, resistance exercise differently influenced MAFbx and MuRF-1 mRNA expression, suggesting both common and divergent regulation of these two ubiquitin ligases.

  • 76.
    Borgenvik, Marcus
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Nordin, Marie
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Enqvist, Jonas K.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Alterations in amino acid concentrations in the plasma and muscle in human subjects during 24 h of simulated adventure racing2012In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 112, p. 3679-3688Article in journal (Refereed)
    Abstract [en]

    This investigation was designed to evaluate changes in plasma and muscle levels of free amino acids during an ultra-endurance exercise and following recovery. Nine male ultra-endurance trained athletes participated in a 24-h standardized endurance trial with controlled energy intake. The participants performed 12 sessions of running, kayaking and cycling (4 x each discipline). Blood samples were collected before, during and after exercise, as well as after 28 h of recovery. Muscle biopsies were taken 1 week before the test and after exercise, as well as after 28 h of recovery. During the 24-h exercise, plasma levels of branched-chain (BCAA), essential amino acids (EAA) and glutamine fell 13%, 14% and 19% (P<0.05) respectively, whereas their concentrations in muscle were unaltered. Simultaneously, tyrosine and phenylalanine levels rose 38% and 50% (P<0.05) in the plasma and 66% and 46% (P<0.05) in muscle, respectively. After the 24-h exercise, plasma levels of BCAA were positively correlated with muscle levels of glycogen (r2=0.73, P<0.05), as was the combined concentrations of muscle tyrosine and phenylalanine with plasma creatine kinase (r2=0.55, P<0.05). Following 28-h of recovery, plasma and muscle levels of amino acids had either returned to their initial levels or were elevated. In conclusion, ultra-endurance exercise caused significant changes elevations in plasma and muscle levels of tyrosine and phenylalanine, which suggest an increase in net muscle protein breakdown during exercise. There was a reduction in plasma concentrations of EAA and glutamine during exercise, whereas no changes were detected in their muscle concentration after exercise.

  • 77. Bouchard, Claude
    et al.
    Antunes-Correa, Ligia M.
    Ashley, Euan A.
    Franklin, Nina
    Hwang, Paul M.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Negrao, Carlos E.
    Phillips, Shane A.
    Sarzynski, Mark A.
    Wang, Ping-yuan
    Wheeler, Matthew T.
    Personalized Preventive Medicine: Genetics and the Response to Regular Exercise in Preventive Interventions2015In: Progress in cardiovascular diseases, ISSN 0033-0620, E-ISSN 1873-1740, Vol. 57, no 4, p. 337-346Article in journal (Refereed)
    Abstract [en]

    Regular exercise and a physically active lifestyle have favorable effects on health. Several issues related to this theme are addressed in this report. A comment on the requirements of personalized exercise medicine and in-depth biological profiling along with the opportunities that they offer is presented. This is followed by a brief overview of the evidence for the contributions of genetic differences to the ability to benefit from regular exercise. Subsequently, studies showing that mutations in TP53 influence exercise capacity in mice and humans are succinctly described. The evidence for effects of exercise on endothelial function in health and disease also is covered. Finally, changes in cardiac and skeletal muscle in response to exercise and their implications for patients with cardiac disease are summarized. Innovative research strategies are needed to define the molecular mechanisms involved in adaptation to exercise and to translate them into useful clinical and public health applications.

  • 78.
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Capacity and hypoxic response of subcutaneous adipose tissue blood flow in humans2014In: Circulation Journal, ISSN 1346-9843, E-ISSN 1347-4820, Vol. 78, no 6, p. 1501-1506Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    The blood flow capacity in subcutaneous adipose tissue in humans remains largely unknown, and therefore the aim of this study was to determine the physiological range of blood flow in this tissue.

    METHODS AND RESULTS:

    The subcutaneous adipose tissue blood flow (ATBF) was measured in 9 healthy young men by positron emission tomography using radiowater tracer. Subcutaneous ATBF was determined in regions adjacent to knee extensors at rest and during dynamic knee extensor exercise, and with 2 physiological perturbations: while breathing moderate systemic hypoxic air (14% O2) at rest and during exercise, and during intra-femoral artery infusion of high-dose adenosine infusion. ATBF was 1.3±0.6ml·100g(-1)·min(-1) at rest and increased with exercise (8.0±3.0ml·100g(-1)·min(-1), P<0.001) and adenosine infusion (10.5±4.9ml·100g(-1)·min(-1), P=0.001), but not when breathing moderate systemic hypoxic air (1.5±0.4ml·100g(-1)·min(-1)). ATBF was similar during exercise and adenosine infusion, but vascular conductance was lower during adenosine infusion. Finally, ATBF during exercise in moderate systemic hypoxia was reduced (6.3±2.2ml·100g(-1)·min(-1)) compared to normoxic exercise (P=0.004).

    CONCLUSIONS:

    The vasodilatation capacity of human subcutaneous adipose blood flow appears to be comparable to, or even higher, than that induced by moderate intensity exercise. Furthermore, the reduced blood flow response in subcutaneous adipose tissue during systemic hypoxia is likely to contribute, in part, to the redistribution of blood flow to exercising muscle in a condition of reduced oxygen availability.

  • 79.
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Functional Response Of Mitochondria To Exercise And Extreme Environments2014In: Acta Physiologica, 212(698), S22, 2014, Vol. 212, no 698, p. S22-Conference paper (Refereed)
  • 80.
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    KCNMA1 encoded cardiac BK channels afford protection against ischemia-reperfusion injury2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9e, no 7, p. 103402.-Article in journal (Refereed)
    Abstract [en]

    Mitochondrial potassium channels have been implicated in myocardial protection mediated through pre-/postconditioning. Compounds that open the Ca2+- and voltage-activated potassium channel of big-conductance (BK) have a pre-conditioning-like effect on survival of cardiomyocytes after ischemia/reperfusion injury. Recently, mitochondrial BK channels (mitoBKs) in cardiomyocytes were implicated as infarct-limiting factors that derive directly from the KCNMA1 gene encoding for canonical BKs usually present at the plasma membrane of cells. However, some studies challenged these cardio-protective roles of mitoBKs. Herein, we present electrophysiological evidence for paxilline- and NS11021-sensitive BK-mediated currents of 190 pS conductance in mitoplasts from wild-type but not BK−/− cardiomyocytes. Transmission electron microscopy of BK−/− ventricular muscles fibres showed normal ultra-structures and matrix dimension, but oxidative phosphorylation capacities at normoxia and upon re-oxygenation after anoxia were significantly attenuated in BK−/− permeabilized cardiomyocytes. In the absence of BK, post-anoxic reactive oxygen species (ROS) production from cardiomyocyte mitochondria was elevated indicating that mitoBK fine-tune the oxidative state at hypoxia and re-oxygenation. Because ROS and the capacity of the myocardium for oxidative metabolism are important determinants of cellular survival, we tested BK−/− hearts for their response in an ex-vivo model of ischemia/reperfusion (I/R) injury. Infarct areas, coronary flow and heart rates were not different between wild-type and BK−/− hearts upon I/R injury in the absence of ischemic pre-conditioning (IP), but differed upon IP. While the area of infarction comprised 28±3% of the area at risk in wild-type, it was increased to 58±5% in BK−/− hearts suggesting that BK mediates the beneficial effects of IP. These findings suggest that cardiac BK channels are important for proper oxidative energy supply of cardiomyocytes at normoxia and upon re-oxygenation after prolonged anoxia and that IP might indeed favor survival of the myocardium upon I/R injury in a BK-dependent mode stemming from both mitochondrial post-anoxic ROS modulation and non-mitochondrial localizations.

  • 81.
    Boushel, Robert
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ara, I
    Gnaiger, E
    Helge, J W
    González-Alonso, J
    Munck-Andersen, T
    Sondergaard, H
    Damsgaard, R
    van Hall, G
    Saltin, B
    Calbet, J A L
    Low-intensity training increases peak arm VO2 by enhancing both convective and diffusive O2 delivery.2014In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 211, no 1, p. 122-134Article in journal (Refereed)
    Abstract [en]

    AIM: It is an ongoing discussion the extent to which oxygen delivery and oxygen extraction contribute to an increased muscle oxygen uptake during dynamic exercise. It has been proposed that local muscle factors including the capillary bed and mitochondrial oxidative capacity play a large role in prolonged low-intensity training of a small muscle group when the cardiac output capacity is not directly limiting. The purpose of this study was to investigate the relative roles of circulatory and muscle metabolic mechanisms by which prolonged low-intensity exercise training alters regional muscle VO2 .

    METHODS: In nine healthy volunteers (seven males, two females), haemodynamic and metabolic responses to incremental arm cycling were measured by the Fick method and biopsy of the deltoid and triceps muscles before and after 42 days of skiing for 6 h day(-1) at 60% max heart rate.

    RESULTS: Peak pulmonary VO2 during arm crank was unchanged after training (2.38 ± 0.19 vs. 2.18 ± 0.2 L min(-1) pre-training) yet arm VO2 (1.04 ± 0.08 vs. 0.83 ± 0.1 L min(1) , P < 0.05) and power output (137 ± 9 vs. 114 ± 10 Watts) were increased along with a higher arm blood flow (7.9 ± 0.5 vs. 6.8 ± 0.6 L min(-1) , P < 0.05) and expanded muscle capillary volume (76 ± 7 vs. 62 ± 4 mL, P < 0.05). Muscle O2 diffusion capacity (16.2 ± 1 vs. 12.5 ± 0.9 mL min(-1)  mHg(-1) , P < 0.05) and O2 extraction (68 ± 1 vs. 62 ± 1%, P < 0.05) were enhanced at a similar mean capillary transit time (569 ± 43 vs. 564 ± 31 ms) and P50 (35.8 ± 0.7 vs. 35 ± 0.8), whereas mitochondrial O2 flux capacity was unchanged (147 ± 6 mL kg min(-1) vs. 146 ± 8 mL kg min(-1) ).

    CONCLUSION: The mechanisms underlying the increase in peak arm VO2 with prolonged low-intensity training in previously untrained subjects are an increased convective O2 delivery specifically to the muscles of the arm combined with a larger capillary-muscle surface area that enhance diffusional O2 conductance, with no apparent role of mitochondrial respiratory capacity.

  • 82.
    Boushel, Robert
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Lundby, Carsten
    Qvortrup, Klaus
    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.
    Mitochondrial plasticity with exercise training and extreme environments.2014In: Exercise and sport sciences reviews, ISSN 0091-6331, E-ISSN 1538-3008, Vol. 42, no 4, p. 169-74Article in journal (Refereed)
    Abstract [en]

    Mitochondria form a reticulum in skeletal muscle. Exercise training stimulates mitochondrial biogenesis, yet an emerging hypothesis is that training also induces qualitative regulatory changes. Substrate oxidation, oxygen affinity, and biochemical coupling efficiency may be regulated differentially with training and exposure to extreme environments. Threshold training doses inducing mitochondrial upregulation remain to be elucidated considering fitness level.

  • 83.
    Boushel, Robert
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Schantz, Peter
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, The Research Unit for Movement, Health and Environment.
    Bengt Saltin: Nekrolog2014Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Bengt Saltin

    Professor Bengt Saltin, Stockholm, har avlidit i en ålder av 79 år. Hans närmast sörjande är Ann-Sofi Colling-Saltin med barnen Ola, Åsa, och Anna med familjer.  

    Bengt Saltin föddes i Ålsten den 3 juni 1935. Han växte upp med modern Margareta och sin sociale far, Sven Saltin, som båda var folkskolelärare. Under läroverkstiden i Södertälje fångade stadens apotekare upp vinnaren vid en terränglöpning och bjöd in honom till en orienteringskurs. Ett livslångt intresse skapades. De bästa ämnena i skolan, svenska språket och svensk litteratur, representerade ett annan viktig ådra. Men det skogliga lockade mest; han ville bli jägmästare. Modern sa dock nej; ”Du ska bli läkare!” Så blev det. Under studier vid Karolinska Institutet rekryterade fysiologen Ulf von Euler honom som amanuens. Bengt nämnde sitt intresse för idrott, varvid han introducerades för professor Erik Hohwü Christensen vid Kungl. Gymnastiska Centralinstitutet.

    Sommaren 1959 inleddes skolningen till arbetsfysiolog. Det första arbetet handlade om det intermittenta arbetets fysiologi, publicerades 1960, och bidrog till intervallträningens utveckling. Det blev tidigt uppenbart att Bengt hade en ovanlig talang för forskning. Efter en centralcirkulatorisk avhandling 1964, med Hohwü Christensen och Per-Olof Åstrand som handledare, visade han även prov på stor självständighet genom att utveckla en ny forskningslinje om skelettmuskulaturen. Den blev snart världsledande. Från 1973 fortsatte Bengt sin bana som professor vid Köpenhamns universitet. Med ett kort undantag vid Karolinska Institutet, förblev Köpenhamn basen för hans gärning. De sista knappa 20 åren ledde han Copenhagen Muscle Research Centre, vars forskning redan är inskriven i vetenskapshistoriska läroböcker.

    Bengt hade en enorm arbetskapacitet, publicerade mer än 440 arbeten, och handledde drygt 40-50 doktorander. Han blev ledamot av Danmarks Kungliga Vetenskapsakademi, hedersdoktor vid tolv universitet, och fick Internationella Olympiska Kommitténs vetenskapliga pris, det finaste man kan få inom det rörelsevetenskapliga fältet. Men för att rätt förstå hans storhet bör man även ha mött honom som den oerhört stimulerande, generösa och stöttande människa han var, och fått ta del av de skarpa samhällsanalyserna samt utblickarna inom litteraturens, teaterns, operans och dansens världar. Han var beundrad av studenter över hela världen för den människa han var, för det arbete han utförde och för det han inspirerade till. Vi sörjer förlusten av en av de riktigt stora inom det arbetsfysiologiska fältet, och en ovanligt klok och vidsynt människa. 

     

    För vänner och kolleger

    Robert Boushel, professor

    Peter Schantz, professor

  • 84.
    Brink-Elfegoun, Thibault
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Holmberg, Hans-Christer
    Nordlund Ekblom, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Neuromuscular and circulatory adaptation during combined arm and leg exercise with different maximal work loads.2007In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 101, no 5, p. 603-11Article in journal (Refereed)
    Abstract [en]

    Cardiopulmonary kinetics and electromyographic activity (EMG) during exhausting exercise were measured in 8 males performing three maximal combined arm+leg exercises (cA+L). These exercises were performed at different rates of work (mean+/-SD; 373+/-48, 429+/-55 and 521+/-102 W) leading to different average exercise work times in all tests and subjects. VO2 reached a plateau versus work rate in every maximal cA+L exercise (range 6 min 33 s to 3 min 13 s). The three different exercise protocols gave a maximal oxygen consumption (VO2MAX) of 4.67+/-0.57, 4.58+/-0.52 and 4.66+/-0.53 l min(-1) (P=0.081), and a maximal heart rate (HRmax) of 190+/-6, 189+/-4 and 189+/-6 beats min(-1) (P=0.673), respectively. Root mean square EMG (EMGRMS) of the vastus lateralis and the triceps brachii muscles increased with increasing rate of work and time in all three cA+L protocols. The study demonstrates that despite different maximal rates of work, leading to different times to exhaustion, the circulatory adaptation to maximal exercise was almost identical in all three protocols that led to a VO2 plateau. The EMG(RMS) data showed increased muscle recruitment with increasing work rate, even though the HRmax and VO2MAX was the same in all three cA+L protocols. In conclusion, these findings do not support the theory of the existence of a central governor (CG) that regulates circulation and neuronal output of skeletal muscles during maximal exercise.

  • 85. Brink-Elfegoun, Tibault
    et al.
    Kaijser, L
    Gustafsson, T
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Maximal oxygen uptake is not limited by a central nervous system governor.2007In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 102, no 2, p. 781-6Article in journal (Refereed)
    Abstract [en]

    We tested the hypothesis that the work of the heart was not a limiting factor in the attainment of maximal oxygen uptake (VO2 max). We measured cardiac output (Q) and blood pressures (BP) during exercise at two different rates of maximal work to estimate the work of the heart through calculation of the rate-pressure product, as a part of the ongoing discussion regarding factors limiting VO2 max. Eight well-trained men (age 24.4 +/- 2.8 yr, weight 81.3 +/- 7.8 kg, and VO2 max 59.1 +/- 2.0 ml x min(-1) x kg(-1)) performed two maximal combined arm and leg exercises, differing 10% in watts, with average duration of time to exhaustion of 4 min 50 s and 3 min 40 s, respectively. There were no differences between work rates in measured VO2 max, maximal Q, and peak heart rate between work rates (0.02 l/min, 0.3 l/min, and 0.8 beats/min, respectively), but the systolic, diastolic, and calculated mean BP were significantly higher (19, 5, and 10 mmHg, respectively) in the higher than in the lower maximal work rate. The products of heart rate times systolic or mean BP and Q times systolic or mean BP were significantly higher (3,715, 1,780, 569, and 1,780, respectively) during the higher than the lower work rate. Differences in these four products indicate a higher mechanical work of the heart on higher than lower maximal work rate. Therefore, this study does not support the theory, which states that the work of the heart, and consequently VO2 max, during maximal exercise is hindered by a command from the central nervous system aiming at protecting the heart from being ischemic.

  • 86. Burke, L M
    et al.
    Castell, L M
    Stear, S J
    Rogers, P J
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Gurr, S
    Mitchell, N
    Stephens, F B
    Greenhaff, P L
    BJSM reviews: A-Z of nutritional supplements2009In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 43, no 14, p. 1088-90Article in journal (Other academic)
  • 87.
    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.
    Kontraindikationer för fysisk aktivitet2016In: FYSS 2017: fysisk aktivitet i sjukdomsprevention och sjukdomsbehandling, Läkartidningen förlag , 2016, p. 227-228Chapter in book (Other academic)
  • 88.
    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 Role Of The Ecg In Cardiovascular Screening Of Athletes2015In: European Journal of Sports Medicine, 3(2015):Suppl. 1 / [ed] Konstantinos Natsis, 2015, Vol. 3, p. 27-28Conference paper (Refereed)
    Abstract [en]

    INTRODUCTION: Sudden cardiac arrest (SCA) in an athlete, is an uncommon event (1/50 000), caused by inherited/congenital cardiovascular disease (in younger athletes, >35 years), while in the older athletes, the cause is most often  underlying coronary artery disease (CAD). Cardiac societies, Sports Medicine Associations and subsequently international sporting bodies have developed cardiac screening programmes to prevent SCA in athletes. In addition, increased  awareness and recommendations regarding arena safety procedures (external automated defibrillators, medical action plans), have been introduced in recent years, to increase the chance of survival in case of a SCA. However, the most appropriate cardiac screening protocol and specifically, the role of the ECG in cardiovascular screening of athletes, is still debated.

    AIM: This talk will discuss the sensitivity and specificity issues, connected with using the ECG or not, as part of cardiovascular screening of athletes.

    MATERIALS AND METHODS: Both the American Heart Association (AHA) and the European Society of Cardiology (ESC) (1) as well as the International Olympic Committee (IOC) recommend regular screening of competitive athletes, including personal and family history and physical examination. However, the AHA does not recommend the routine use of the ECG in screening. In recent years, more evidence has emerged, making it possible to scrutinize the literature regarding sensitivity/specificity for screening with/without ECG.

    RESULTS: Firstly, the available literature show that cardiovascular screening including an ECG will have much superior sensitivity for finding underlying relevant cardiac abnormalities. Traditionally, ECG has been found to also have a large number of false-positives, making the specificity of including the ECG low. However, in recent years, the international consensus-statements on ECG interpretation in athletes, have been repeatedly updated, due to scientific progress, making the specificity of cardiac screening with the ECG much higher, with unchanged high sensitivity (2). On the contrary, cardiac screening without the ECG has been shown to have a very low sensitivity, but more importantly will probably have also a low specificity, since many athletes do have a variety of often diffuse symptoms, which will necessitate further investigation, most readily an ECG. The few available cost-effectiveness studies worldwide, have shown that screening with the ECG is more cost-effective than screening without, but more high quality studies, are needed on cost-effectiveness.

    CONCLUSION: Cardiovascular screening of athletes aims to prevent sudden cardiac arrest (and death) of athletes. The inclusion of an ECG in regular screening, will be accompanied by higher sensitivity, while the specificity using this approach has increased considerably in recent years. All in all, ECG should be an integral part of cardiovascular screening of athletes, and is also recommended by EFSMA in its latest statement on pre-participation examination in sports (3).

  • 89.
    Börjesson, Mats
    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.
    Forssblad, Magnus
    Karlsson, Jon
    Univ Gothenburg, Gothenburg, Sweden..
    Can you feel the real paper?2015In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 49, no 22, p. 1419-1420Article in journal (Other academic)
  • 90.
    Börjesson, Mats
    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.
    Forssblad, Magnus
    Karlsson, Jón
    Looking back over 20 years of sports medicine prevention and treatment: progress, but still a lot to achieve.2015In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 49, no 22, article id 1421Article in journal (Refereed)
  • 91.
    Börjesson, Mats
    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.
    Karlsson, Jon
    Ethical dilemmas faced by the team physician: overlooked in sports medicine education?2014In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 48, no 19, p. 1398-1399Article in journal (Refereed)
    Abstract [en]

    The authors reflect on the ethical issues facing team physicians in soccer. They argue that sports ethics may have been overlooked in sports medicine education. The ethical issues highlighted by the authors include the substitution of star players, the return of soccer players following concussion and the importance of collaboration between team physicians and team managers.

  • 92.
    Börjesson, Mats
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Karlsson, Jon
    Lagläkarens många dilemman2014In: I gråzonen: En antologi om idrottens etiska utmaningar / [ed] Christine Dartsch, Johan R. Norberg & Johan Pihlblad, Stockholm: Centrum för Idrottsforskning , 2014, p. 179-91Chapter in book (Other academic)
  • 93.
    Börjesson, Mats
    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.
    Karlsson, Jon
    Swedish sports medicine is alive and well!2014In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 48, no 19, p. 1397-1397Article in journal (Other academic)
    Abstract [en]

    An introduction is presented in which the authors discuss various reports within the issue on topics including exercise, concussion and sports ethics.

  • 94.
    Börjesson, Mats
    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.
    Karlsson, Jón
    Lagläkarens många dilemman2014In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 23, no 2, p. 38-42Article in journal (Other academic)
    Abstract [sv]

    Hur hanterar egentligen en lagläkare sin dubbla lojalitet, mellan omsorgen om spelarnas hälsa och en förståelse för klubbens sportsliga ambitioner? En lagläkare möter många och skilda etiska dilemman både på och utanför planen. Du gör en läkarundersökning i samband med att en ny spelare ska skriva på för klubben. Du vet att styrelsen och tränaren har stora förväntningar på spelaren. Det lukrativa kontraktet är redan påskrivet. Endast läkarundersökningen återstår. Vid undersökningen hittar du en korsbandsskada i ena knät. Det visar sig att spelaren skadade sig vid den sista seriematchen tre månader tidigare. Spelaren förbjuder dig att prata om detta med klubben och hänvisar till sekretess. Hur gör du nu? Den här artikeln tar upp ett antal etiska problem inom idrottsmedicinen. Det finns i dag ingen specifik utbildning i hur läkare ska hantera den här typen av frågor, men de diskuteras ofta när fotbollens lagläkare träffas. Artikeln är ett utdrag ur antologin I gråzonen utgiven av Centrum för idrottsforskning. Författarna har båda lång erfarenhet av rollen som lagläkare i fotboll, både på nationell och på internationell nivå. Jón Karlsson har varit läkare för IFK Göteborgs juniorer och A-lag sedan år 1984, och för de svenska U21- och OS-landslagen för herrar under en tioårsperiod. Mats Börjesson har varit lagläkare för herrlaget GAIS sedan 1995, för svenska damlandslaget sedan 2009, för damlaget Tyresö FF 2012-2013 samt för Elfenbenskustens lag i VM för herrar 2010.

  • 95.
    Börjesson, Mats
    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.
    Onerup, Aron
    Sahlgrenska universitetssjukhuset, Göteborg.
    Lundqvist, Stefan
    Primärvården Göteborg.
    Dahlöf, Björn
    Sahlgrenska akademin, Göteborg.
    Fysisk aktivitet vid hypertoni2016In: FYSS 2017: fysisk aktivitet i sjukdomsprevention och sjukdomsbehandling, Läkartidningen förlag , 2016, p. 412-425Chapter in book (Other academic)
    Abstract [sv]

    Sammanfattande rekommendation

    Personer med hypertoni bör rekommenderas aerob fysisk aktivitet för att sänka blodtrycket. Måttligt starkt vetenskapligt underlag (evidensstyrka +++).

    Personer med hypertoni kan som tillägg rekommenderas isometrisk träning för att sänka blodtrycket. Begränsat vetenskapligt underlag (evidensstyrka ++).

    Personer med hypertoni bör även rekommenderas muskelstärkande fysisk aktivitet enligt de allmänna rekommendationerna om fysisk aktivitet.

    Personer med hypertoni bör rekommenderas regelbunden fysisk aktivitet som en av flera åtgärder för att sänka blodtrycket.

  • 96.
    Börjesson, Mats
    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.
    Solberg, Erik Ekker
    Diakonhjemmets sykehus, Oslo.
    Nylander, Eva
    Universitetssjukhuset Linköping.
    Plötslig hjärtdöd vid fysisk aktivitet2016In: FYSS 2017: fysisk aktivitet i sjukdomsprevention och sjukdomsbehandling, Läkartidningen förlag , 2016, p. 241-249Chapter in book (Other academic)
    Abstract [sv]

    Sammanfattning

    Regelbunden fysisk aktivitet har positiva effekter på såväl riskfaktorer för hjärtkärlsjukdom som etablerad hjärt-kärlsjukdom. Aerob fysisk aktivitet på måttlig intensitet rekommenderas allmänt. Mer fysisk aktivitet på hög intensitet har potentiellt ännu större effekt, men kan också medföra ökade risker för personer med bakomliggande hjärt-kärlsjukdom.

    Plötslig hjärtdöd i samband med fysisk aktivitet bland individer > 35 år orsakas nästan uteslutande av kranskärlssjukdom. För äldre idrottare (> 35 år), liksom för icke elitaktiva, saknas i dag svenska rekommendationer om hjärtscreening. Självskattningsformulär, i utvalda fall kompletterat med hjärtundersökning hos ordinarie läkare, har föreslagits kunna minska risken i denna grupp.

    Plötsliga dödsfall under idrottsutövning bland unga (< 35 år) beror vanligen på tidigare odiagnostiserade medfödda eller ärftliga hjärtsjukdomar. Riksidrottsförbundet (RF) och Socialstyrelsen rekommenderar riktade hjärtkontroller av unga elitidrottare från 16 års ålder, bestående av familjehistoria, symtom, fysikalisk undersökning och vilo-EKG.

  • 97.
    Börjesson, Mats
    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.
    Vanhees, Luc
    Leuven University.
    Cardiovascular evaluation of middle-aged/senior leisure time athletes2013In: Cardiac Electrophysiology Clinics, ISSN 1877-9182, Vol. 5, no 1, p. 33-42Article, review/survey (Refereed)
  • 98. Calbet, J A L
    et al.
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Robach, P
    Hellsten, Y
    Saltin, B
    Lundby, C
    Chronic hypoxia increases arterial blood pressure and reduces adenosine and ATP induced vasodilatation in skeletal muscle in healthy humans.2014In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 211, no 4, p. 574-84Article in journal (Refereed)
    Abstract [en]

    AIMS: To determine the role played by adenosine, ATP and chemoreflex activation on the regulation of vascular conductance in chronic hypoxia.

    METHODS: The vascular conductance response to low and high doses of adenosine and ATP was assessed in ten healthy men. Vasodilators were infused into the femoral artery at sea level and then after 8-12 days of residence at 4559 m above sea level. At sea level, the infusions were carried out while the subjects breathed room air, acute hypoxia (FI O2 = 0.11) and hyperoxia (FI O2 = 1); and at altitude (FI O2 = 0.21 and 1). Skeletal muscle P2Y2 receptor protein expression was determined in muscle biopsies after 4 weeks at 3454 m by Western blot.

    RESULTS: At altitude, mean arterial blood pressure was 13% higher (91 ± 2 vs. 102 ± 3 mmHg, P < 0.05) than at sea level and was unaltered by hyperoxic breathing. Baseline leg vascular conductance was 25% lower at altitude than at sea level (P < 0.05). At altitude, the high doses of adenosine and ATP reduced mean arterial blood pressure by 9-12%, independently of FI O2 . The change in vascular conductance in response to ATP was lower at altitude than at sea level by 24 and 38%, during the low and high ATP doses respectively (P < 0.05), and by 22% during the infusion with high adenosine doses. Hyperoxic breathing did not modify the response to vasodilators at sea level or at altitude. P2Y2 receptor expression remained unchanged with altitude residence.

    CONCLUSIONS: Short-term residence at altitude increases arterial blood pressure and reduces the vasodilatory responses to adenosine and ATP.

  • 99. Calbet, J A L
    et al.
    Mortensen, S P
    Munch, G D W
    Curtelin, D
    Boushel, Robert
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Constant infusion transpulmonary thermodilution for the assessment of cardiac output in exercising humans.2016In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 26, no 5, p. 518-527Article in journal (Refereed)
    Abstract [en]

    To determine the accuracy and precision of constant infusion transpulmonary thermodilution cardiac output (CITT-Q) assessment during exercise in humans, using indocyanine green (ICG) dilution and bolus transpulmonary thermodilution (BTD) as reference methods, cardiac output (Q) was determined at rest and during incremental one- and two-legged pedaling on a cycle ergometer, and combined arm cranking with leg pedaling to exhaustion in 15 healthy men. Continuous infusions of iced saline in the femoral vein (n = 41) or simultaneously in the femoral and axillary (n = 66) veins with determination of temperature in the femoral artery were used for CITT-Q assessment. CITT-Q was linearly related to ICG-Q (r = 0.82, CITT-Q = 0.876 × ICG-Q + 3.638, P < 0.001; limits of agreement ranging from -1.43 to 3.07 L/min) and BTD-Q (r = 0.91, CITT-Q = 0.822 × BTD + 4.481 L/min, P < 0.001; limits of agreement ranging from -1.01 to 2.63 L/min). Compared with ICG-Q and BTD-Q, CITT-Q overestimated cardiac output by 1.6 L/min (≈ 10% of the mean ICG and BTD-Q values, P < 0.05). For Q between 20 and 28 L/min, we estimated an overestimation < 5%. The coefficient of variation of 23 repeated CITT-Q measurements was 6.0% (CI: 6.1-11.1%). In conclusion, cardiac output can be precisely and accurately determined with constant infusion transpulmonary thermodilution in exercising humans.

  • 100. Calbet, Jose A L
    et al.
    Boushel, Robert C
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Assessment of cardiac output with transpulmonary thermodilution during exercise in humans.2015In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 118, no 1, p. 1-10Article in journal (Refereed)
    Abstract [en]

    The accuracy and reproducibility of transpulmonary thermodilution (TPTd) to assess cardiac output (Q) in exercising men was determined using indocyanine green (ICG) dilution as a reference method. TPTd has been utilized for the assessment of Q and preload indices of global end-diastolic volume (GEDV) and intrathoracic blood volume (ITBV), as well as extravascular lung water (EVLW) in resting humans. It remains unknown if this technique is also accurate and reproducible during exercise. Sixteen healthy men underwent catheterization of the right femoral vein (for iced saline injection), an antecubital vein (ICG injection) and femoral artery (thermistor) to determine their Q by TPTd and [ICG] during incremental 1 and 2-legged pedaling on a cycle ergometer, and combined arm cranking with leg pedaling to exhaustion. There was a close relationship between Td-Q and ICG-Q (r=0.95, n=151, SEE: 1.452 L/min, P<0.001; mean difference of 0.06 L/min; limits of agreement -2.98 to 2.86 L/min), and TPTd-Q and ICG-Q increased linearly with VO2 with similar intercepts and slopes. Both methods had mean coefficients of variation (CV) close to 5% for Q, GEDV and ITBV. The mean CV of EVLW, assessed with both indicators (ICG and thermal) was 17%, and was sensitive enough as to detect a reduction in EVLW of 107 ml when changing from resting supine to upright exercise. In summary, transpulmonary thermodilution with bolus injection into the femoral vein is an accurate and reproducible method to assess cardiac output during exercise in humans.

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