The Coastal Challenge

Pierre took on this six-day epic challenge with his mind set on a first place finish. Unfortunately, he rolled his ankle on day two, which quashed his hopes, but he soldiered on to eventually finish in 7th. It turned out that crossing the finish line at all was a valiant effort, given the results of his MRI scan which revealed he’d actually fractured his ankle before running on it for another 29 cumulative hours.

When an athlete builds up a significant level of dehydration in hot and humid environments like in Costa Rica, the gut can become less efficient at absorbing fuel. The fact that Pierre didn’t experience any gastrointestinal discomfort throughout the entirety of this race, despite significantly under-drinking relative to his very high sweat losses, is a testament to his well thought out fueling strategy and significant gut training beforehand.

Pierre has a lot of experience with racing events in the heat, including as part of the winning Marathon Des Sables team in 2023. He knew before this event that his sweat rate can be up to 2.5L per hour in very hot and humid conditions, meaning his hydration strategy would be very important. Pierre’s injury early on in the race meant he was exposed to the heat and humidity for much longer than he had originally anticipated, producing more sweat to cool his body down and accumulating a greater level of fluid deficit than his strategy accounted for. Ultimately, this meant he likely experienced dehydration beyond the scientifically accepted threshold for performance decline of ~2-4% body weight loss. Later in the week, Pierre had spent so much additional time out on course, he actually ran out of the hydration supplies he brought with him so had to rely on aid stations. Because of this he significantly under-replaced sodium relative to his sweat losses on the final day.

Pierre chose to not use caffeine as an ergogenic aid for this event. He tends to utilise it for shorter events like the Valencia Marathon where he could really feel the immediate performance boost, rather than drip feeding it into his longer days on the trails. Many ultra runners do use caffeine as a way of reducing their perceived exertion and increasing focus when they’ve accumulated a lot of mental fatigue, so it may be worth introducing for his next event, especially in the latter days.