Most of the focus has been on the analysis of nutritional and fluid intake.

Ultramarathon races (> 42.195 km) have gained popularity in the last two decades and are now used as experimental models to assess the effects of sleep deprivation and muscular and cardiac damage. Overall, almost all of these elite 24-h ultramarathoners surpassed the nutritional recommendations without encountering significant or the usual adverse effects. Performance (distance ran) positively correlated with energy intake ( ρ = 0.674, p = 0.023) and negatively ( ρ = − 0.776, p = 0.005) with fluid intake. The athletes were not dehydrated, shown by the absence of significant body mass loss (− 0.92 ± 2.13%) and modifications of plasma osmolality and an increase in plasma volume (+ 19.5 ± 15.8%). Such unusually high intake was not accompanied by detrimental GIS (recorded in 75%, but only transiently ) or EAH (0%). The calculated energy balance remained, however, largely negative (− 29.5 ± 16.1 MJ). Individual analyses showed that all but one (for fluid intake) or two (for energy and carbohydrate intake) consumed more than the minimum recommendations.

GIS, markers of dehydration (body mass modifications, plasma and urine osmolality, and plasma volume samples obtained 26 h before and just after the race) and EAH (plasma and urine sodium concentrations) were also assessed. MethodsĪd libitum food and fluid intake was recorded in real-time and energy, macronutrient, sodium, and caffeine intake then calculated using a spreadsheet in which the nutritional composition of each item was previously recorded.

We hypothesized that these elite athletes would easily comply these recommendations without exhibiting detrimental adverse symptoms. We analyzed such intake for 12 twelve elite athletes (6 males and 6 females age: 46 ± 7 years, height: 170 ± 9 cm, weight: 61.1 ± 9.6 kg, total distance run: 193–272 km) during the 2019 24-h World Championships and compared it to the latest nutritional recommendations described by the International Society of Sports Nutrition in 2019. Properly replacing energy and fluids is a challenge for 24-h ultramarathoners because such unusually high intake may induce adverse effects (gastrointestinal symptoms and exercise-associated hyponatremia ).

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