Compromised Energy and Macronutrient Intake of Ultra-endurance Runners During a Multi-stage Ultra-marathon Conducted in a Hot Ambient Environment

Abstract

Energy and macronutrient intake of ultra-endurance runners (UER n=74; control (CON) n=12) during a 5-days 225km mult i-stage ultra-marathon (MSUM ) in the heat (Tmax 32-40˚C), were determined through dietary recall interview and analysed by dietary analysis software. Body mass (BM) and urinary ketones were determined pre- and post-stage. Recovery, appetite and gastrointestinal symptoms were mon itored daily. Pre-stage BM, total daily energy (overall mean : 3348kcal/day), protein (1.5g/kgBM/day), carbohydrate (7.5g/kg BM/day) and fat (1.4g/kg BM/day) intakes did not differ between stages in UER. CON presented a daily macronutrient profile closer to benchmark reco mmendations than UER. Carbohydrate intake pre-stage (102g), during running (24g/h) and immed iately post-stage (1.7g/kg BM), and protein intake post-stage (0.3g/kgBM) did not differ between stages, and were below benchmark reco mmendations in the majority of UER. Post-stage urinary ketones increased in UER as competit ion progressed (Stage 1: 16% vs. Stage 5: 32%). Gastrointestinal distresses and appetite suppression were reported by 85% and 72% of UER, respectively, along the MSUM. Correlations between subjective symptomology, energy and carbohydrate intakes were observed in UER (P<0.05). Sub-optimal macronutrient profile, carbohydrate intake, and recovery nutrition throughout the MSUM suggests energy quantity and quality may be compro mised in ultra-runners along competition; indicating that specialised nutritional education may be beneficial in this population.