Within-day energy deficiency and metabolic perturbation in male endurance athletes

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Monica K Torstveit, Ida Lysdahl Fahrenholtz, Thomas B Stenqvist, Øystein Sylta, Anna Katarina Melin

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 (WDEB) in male athletes with suppressed and normal resting metabolic rate (RMR) and explore if within-day energy deficiency (WDED) is associated with endocrine markers of energy deficiency. Thirty-one 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 (EA), 24-hour energy balance (EB) and WDEB in 1-hour 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 RMR (RMRratio> 0.90, n=11). Despite no observed differences in 24-hour EB or EA between the groups, subjects with suppressed RMR spent more time in an energy deficit exceeding 400 kcal (20.9 [18.8 - 21.8] hours vs. 10.8 [2.5 - 16.4], P=0.023), and had larger single-hour energy deficits compared to subjects with normal RMR (3265 ± 1963 kcal vs. -1340 ± 2439, P=0.023). Larger single-hour energy deficits were associated with higher cortisol levels (r = -0.499, P=0.004) and a lower testosterone:cortisol ratio (r = 0.431, P=0.015), but no associations with T3or fasting blood glucose were observed. In conclusion, WDED was associated with suppressed RMR and catabolic markers in male endurance athletes.

Original languageEnglish
JournalInternational Journal of Sport Nutrition & Exercise Metabolism
Volume28
Issue number4
Pages (from-to)419-427
Number of pages9
ISSN1526-484X
DOIs
Publication statusPublished - 2018

ID: 190669374