Energy turnover during 24 hours and 6 days of adventure racing

Abstract

Energy turnover was assessed in two conditions of mixed ultra-endurance exercise. In Study 1, energy expenditure and intake were measured in nine males in a laboratory over 24 h. In Study 2, energy expenditure was assessed in six males during an 800-km Adventure race (mean race time 152.5 h). Individual correlations between heart rate and oxygen uptake (VO(2)) were established during pre-tests when kayaking, cycling, and running. During exercise, energy expenditure was estimated from continuous heart rate recordings. Heart rate and VO(2) were measured regularly during fixed cycling work rates to correct energy expenditure for drift in oxygen pulse. Mean energy expenditure was 18,050 +/- 2,390 kcal (750 +/- 100 kcal h(-1)) and 80,000 +/- 18,000 kcal (500 +/- 100 kcal h(-1)) in Study 1 and Study 2 respectively, which is higher than previously reported. Energy intake in Study 1 was 8,450 +/- 1,160 kcal, resulting in an energy deficit of 9,590 +/- 770 kcal. Body mass decreased in Study 1 (-2.3 +/- 0.8 kg) but was unchanged in Study 2. Fat mass decreased in Study 2 (-2.3 +/- 1.5 kg). In Study 1, muscle glycogen content decreased by only 60%. Adventure racing requires a high energy expenditure, with large inter-individual variation. A large energy deficit is caused by inadequate energy intake, possibly due to suppressed appetite and gastrointestinal problems. The oxygen pulse, comparing start to 12 h of exercise and beyond, increased by 10% and 5% in Study 1 and Study 2 respectively. Hence, estimations of energy expenditure from heart rate recordings should be corrected according to this drift.

“It’s Not About Taking the Easy Road”: The Experiences of Ultramarathon Runners

“…Furthermore, after completing a UM event runners experience decreased tension and vigor, but greater fatigue. The latter results are not surprising given the physiological demands required to finish a UM race (Davies & Thompson, 1986;Enqvist et al, 2010). Evaluations of UM runners' cognitive orientations, race thoughts and mental strategies indicate that these runners are more confident, committed to running, have higher goal-orientations compared with other athletes, use dissociative thoughts (e.g., thinking of friends, music) and use several mental skills (i.e., imagery, goal setting, self-talk; Acevedo et al, 1992).…”

Isoform-specific alanine aminotransferase measurement can distinguish hepatic from extrahepatic injury in humans

“…In total, 8 women and 31 men performed mixed ultra-endurance exercise of running, trekking, kayaking, cycling and climbing in 3 different adventure races with average finishing race times of 48, 72 and 150 h, respectively (15)(16)(17)(18). Average energy expenditure including sleep and rest was ~525 kcal/h, corresponding to ~40% of individual maximal oxygen uptake (18). Energy, water intake and time for rest were ad libitum.…”

Changes in single skinfold thickness in 100 km ultramarathoners

“…A decrease in body mass is a common finding in ultraendurance performance 1,2. Generally, the decrease in body mass during endurance performance is considered to be due to dehydration 3–5.…”