AUTHOR=Kinrade Emma J. , Galloway Stuart D. R. 

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

JOURNAL=Frontiers in Physiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.765888

DOI=10.3389/fphys.2021.765888

ISSN=1664-042X

ABSTRACT=<p>Carbohydrate (CHO) intake recommendations for events lasting longer than 3h indicate that athletes should ingest up to 90g.h.<sup>−1</sup> of multiple transportable carbohydrates (MTC). We examined the dietary intake of amateur (males: <italic>n</italic>=11, females: <italic>n</italic>=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 <italic>via</italic> 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<sup>−1</sup>; 42±9% of total energy), although pre-race meal CHO intake was within recommended levels (1.5±0.7g·kg<sup>−1</sup>). In-race CHO intake was only in the 30–60g·h<sup>−1</sup> range (mean intake 33±12g·h<sup>−1</sup>) with suboptimal amounts of multiple transportable CHO consumed. Exercise intensity was low to moderate (mean 68%HR<sub>max</sub> 45%VO<sub>2max</sub>) 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 <italic>t</italic>-tests showed significantly different distances achieved by runners consuming ≥5 vs. &lt;5g·kg<sup>−1</sup> CHO in pre-race diet [98.5±18.7miles (158.5±30.1km) vs. 78.0±13.5miles (125.5±21.7km), <italic>p</italic>=0.04] and ≥40 vs. &lt;40g·h<sup>−1</sup> CHO in-race [92.2±13.9miles (148.4±22.4km) vs. 74.7±13.5miles (120.2±21.7km), <italic>p</italic>=0.02]. Pre-race CHO intake was positively associated with ultra-running experience, but no association was found between ultra-running experience and race distance. No association was observed between mean interstitial glucose and dietary intake, or with race distance. Further research should explore approaches to meeting pre-race dietary CHO intake as well as investigating strategies to boost in-race intake of multiple transportable CHO sources. In 24-h ultra-runners, studies examining the performance enhancing benefits of getting closer to meeting pre-race and in-race carbohydrate recommendations are required.</p>