Mathilde Cartier
IRONMAN® World Championships
NiceTop 100, F30-34Mathilde 's headline numbers
Mathilde 's strategy
Fueling
T - 1-4hrs: Ate a carb rich meal (Low in fat & fibre)
T - 15mins: Took in a final dose of carb
"Despite the tough first 2 hours on the bike, looking back I feel like I could have pushed more."
Mathilde fell short of the recommended carb intake for a race of this duration and intensity, likely due to the GI issues she suffered during the race, which she thinks was due to eating too soon pre-swim. She rated her overall stomach comfort throughout the event 4 out of 10, mostly affecting her for the first 2 hours of the bike leg and then when she transitioned onto the run course. That being said, Mathilde still consumed a solid 77g/h whilst on the bike. However, this decreased by almost 40% during the run, as GI issues prevented her from having her other flask of Flow Gel with another 100 grams of carbohydrate.
Hydration
Taking on board an appropriate amount of fluid and sodium is essential to maintaining blood volume and supporting the cardiovascular effort needed to perform on race day.
Whilst the absolute amount of sodium and fluid consumed per hour is important, it’s critical to consider these in relation to each other. This is known as 'relative sodium concentration' and it’s expressed in milligrams per litre (mg/L). How much sodium you’re taking in per litre of fluid is more important than the absolute amount taken in per hour.
Drinking a strong electrolyte drink before the race could have helped Mathilde start optimally hydrated
"It wasn’t too hot during the race, and I felt in control of my hydration strategy. "
Mathilde should consider using a more effective preloading protocol before races by using PH 1500 instead of PH 1000, as this higher concentration of sodium has been shown to maximise blood volume and hydration status. She didn’t suffer from any cramping at all during the race, suggesting she likely replenished enough of her sodium and fluid losses. Going forward, it would be worth Mathilde getting a Sweat Test and start collecting more sweat rate data to help dial in her hydration strategy, which becomes increasingly important when racing in hotter conditions.
Caffeine
Beyond the Three Levers of Performance (carb, sodium and fluid), caffeine is one of only a few substances that is proven to improve performance for most endurance athletes as it can help stave off mental and physical fatigue.
T - 0-4hrs: Had a final hit of caffeine
Mathilde’s only source of caffeine during the race came from the cola she drank whilst on the run course. For future races, she could consider incorporating slightly more of the stimulant into her strategy to benefit from the many ergogenic benefits that it provides. Trialling this in training ahead of time will be important to make sure she doesn’t have any adverse symptoms to using higher amounts of caffeine.
How Mathilde hit her numbers
Here's everything that Mathilde ate and drank on the day...
Final thoughts
“I was glad to get round. Unfortunately, my GI issues on part of the bike leg and going into the run prevented me from eating more and ultimately, hindered my performance. ”
“Mathilde intended to consume a lot more carbs during the IRONMAN® World Championships in Nice, but ultimately her GI discomfort prevented this. Nevertheless, she stayed positive and fueled where possible to try and support her energy levels. With some more gut training, dialling in her hydration strategy and adding additional caffeine into her plan, Mathilde can most certainly look forward to performance gains in 2025. ”
PF&HMathilde 's full stats
Data Confidence
We rate each of our case studies from 1-5 based on the level of accuracy, and our confidence in the data.
There is some confidence in the quantities and brands of products consumed but the data may lack specifics (e.g. volumes specific flavours). A high number of estimations have been made and the room for error is moderate-high. There may also be the possibility that some intake has been grossly over- or under-estimated.