This talk will focus on the major nutritional and physiological factors that influence ultra-endurance exercise performance in both recreational and elite athletes.
Empirical observations show that athletes who have been engaged in ultra-endurance sports for several years have a large advantage compared to novices in the sport. It depends of course in part on the fact that they are more experienced, but even athletes from traditional endurance sports with a documented higher aerobic capacity (i.e., higher VO2max) have difficulties to keep up with ultra-endurance specialists when exercise duration exceeds three or four hours. This indicates that fatigue and performance in ultra-endurance exercise is determined by (in part) other factors compared to traditional endurance sports.
Ultra-endurance sports vary in form and duration, such as running or adventure racing (AR) from 6 h to more than 6 days, but are no matter the nature of the specific competition still in many aspects extreme sports.
The athletes do not generally need to perform at high maximum speeds, but the energy expenditure is extremely high. The total energy expenditure for a 24-h AR is approximately 18-20 000 kcal, which is almost 10 times more than normal basal metabolism (Enqvist et al. 2010). One reason for fatigue is that the energy deficit is substantial, also the profile of amino acids in blood and muscle change during races (Borgenvik et al. 2012), possibly contributing to the central fatigue that has been described in other studies.
As for the physiological factors, our research group and collaborators have investigated many aspects of the versatile physiological adaptation to ultra-endurance exercise, such as circulatory adaptations and cardiac fatigue (Mattsson 2011, Mattsson et al. 2010, 2011) muscular damage (Wichardt et al 2011, Marklund et al 2013), hormonal status (Berg et al 2008), and immunological response (Wallberg et al 2011).
The effect of sleep deprivation on both mental and physiological functions during the races must also be included in the total complex of factors limiting performance.
19th Annual Congress of the European College of Sport Science (ECSS), Amsterdam, Netherlands, 2-5 July 2014