Dietary Observations of Ultra-Endurance Runners in Preparation for and During a Continuous 24-h Event

Abstract

Carbohydrate (CHO) intake recommendations for events lasting longer than 3h indicate that athletes should ingest up to 90g.h.−1 of multiple transportable carbohydrates (MTC). We examined the dietary intake of amateur (males: n=11, females: n=7) ultra-endurance runners (mean age and mass 41.5±5.1years and 75.8±11.7kg) prior to, and during a 24-h ultra-endurance event. Heart rate and interstitial glucose concentration (indwelling sensor) were also tracked throughout the event. Pre-race diet (each 24 over 48h) was recorded via weighed intake and included the pre-race meal (1–4h pre-race). In-race diet (24h event) was recorded continuously, in-field, by the research team. Analysis revealed that runners did not meet the majority of CHO intake recommendations. CHO intake over 24–48h pre-race was lower than recommended (4.0±1.4g·kg−1; 42±9% of total energy), although pre-race meal CHO intake was within recommended levels (1.5±0.7g·kg−1). In-race CHO intake was only in the 30–60g·h−1 range (mean intake 33±12g·h−1) with suboptimal amounts of multiple transportable CHO consumed. Exercise intensity was low to moderate (mean 68%HRmax 45%VO2max) meaning that there would still be an absolute requirement for CHO to perform optimally in this ultra-event. Indeed, strong to moderate positive correlations were observed between distance covered and both CHO and energy intake in each of the three diet periods studied. Independent t-tests showed significantly different distances achieved by runners consuming ≥5 vs.