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- Title
Within-Day Energy Deficiency and Metabolic Perturbation in Male Endurance Athletes.
- Authors
Torstveit, Monica Klungland; Fahrenholtz, Ida; Stenqvist, Thomas B.; Sylta, Øystein; Melin, Anna
- Abstract
Endurance athletes are at increased risk of relative energy deficiency associated with metabolic perturbation and impaired health. We aimed to estimate and compare within-day energy balance in male athletes with suppressed and normal resting metabolic rate (RMR) and explore whether within-day energy deficiency is associated with endocrine markers of energy deficiency. A total of 31 male cyclists, triathletes, and long-distance runners recruited from regional competitive sports clubs were included. The protocol comprised measurements of RMR by ventilated hood and energy intake and energy expenditure to predict RMRratio (measured RMR/predicted RMR), energy availability, 24-hr energy balance and within-day energy balance in 1-hr intervals, assessment of body composition by dual-energy X-ray absorptiometry, and blood plasma analysis. Subjects were categorized as having suppressed (RMRratio < 0.90, n = 20) or normal (RMRratio > 0.90, n = 11) RMR. Despite there being no observed differences in 24-hr energy balance or energy availability between the groups, subjects with suppressed RMR spent more time in an energy deficit exceeding 400 kcal (20.9 [18.8–21.8] hr vs. 10.8 [2.5–16.4], p =.023) and had larger single-hour energy deficits compared with subjects with normal RMR (3,265 ± 1,963 kcal vs. −1,340 ± 2,439, p =.023). Larger single-hour energy deficits were associated with higher cortisol levels (r = −.499, p =.004) and a lower testosterone:cortisol ratio (r =.431, p =.015), but no associations with triiodothyronine or fasting blood glucose were observed. In conclusion, within-day energy deficiency was associated with suppressed RMR and catabolic markers in male endurance athletes.
- Subjects
NUTRITION disorders; BODY composition; ENDOCRINE system physiology; BASAL metabolism; BIOMARKERS; BLOOD plasma; BLOOD sugar; BLOOD volume; CYCLING; ENDURANCE sports; ENERGY metabolism; FASTING; HYDROCORTISONE; INGESTION; METABOLISM; TESTOSTERONE; TRIATHLON; TRIIODOTHYRONINE; SPORTS events; LONG-distance running; MALE athletes; PHOTON absorptiometry; DISEASE risk factors
- Publication
International Journal of Sport Nutrition & Exercise Metabolism, 2018, Vol 28, Issue 4, p419
- ISSN
1526-484X
- Publication type
Article
- DOI
10.1123/ijsnem.2017-0337