
Rebecca Clarke
IRONMAN® European Championship
Rebecca's headline numbers
Rebecca's strategy
Fueling
T - 1-4hrs: Ate a carb rich meal (Low in fat & fibre)
T - 15mins: Took in a final dose of carb
"I spent too long chasing without taking enough fuel in, so I finished the bike leg feeling quite low on energy."
After a drop in energy going into the run at her previous race, IRONMAN® New Zealand, Rebecca wanted to combat this by taking an extra PF 30 Caffeine Gel during the bike, along with an extra PF 30 Chew to increase her carb intake prior to the run. Despite this tweak to her fueling, she still felt the effects of her hard efforts on the bike later on in the race. Going forward, she plans to undergo some gut training to allow her to increase her carb intake without risking GI discomfort and hopefully keep energy levels higher for longer.
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.
Rebecca553mg/L
Rebecca has been Sweat Tested to dial in her hydration plan
Sweat sodium concentration (mg/L) is largely genetically determined and remains relatively stable. Knowing how salty your sweat is enables you to replace a good proportion of your sweat losses, which can range from 200-2,000mg/L.
Whilst Rebecca's losses are on the low side, getting her hydration strategy right is still crucial when it's hot and/or humid as her higher sweat rate in these conditions can result in significant net losses over the duration of a race.
Learn moreT - 60mins: Drank ~500ml of strong electrolyte drink
"I felt I hydrated well, and needed to pee near the start of the run."
Rebecca had two bottles on the bike, one with 1.5 servings of PF Carb & Electrolyte Drink Mix and the other with PH 1500 (Drink Mix). To top up her sodium intake, she also incorporated two Electrolyte Capsules. As someone with a low sweat sodium concentration, this hydration strategy on the bike likely replaced a good amount of her losses. On the run, Rebecca managed to maintain her hydration status by carrying a Soft Flask of PH 1000 (Drink Mix), as well as picking up plain water and cola from the on-course aid stations.
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.
Consuming caffeine in the hours before the start may have increased perceived energy levels
Rebecca had a high caffeine intake during the race, primarily through PF 30 Caffeine Gels. Although this was significantly above the recommendations, she regularly consumes this large quantity of caffeine with no negative side effects, demonstrating that she has a high caffeine tolerance. The timing of her caffeine doses may be a helpful tweak, placing larger amounts at the end of the bike when she tends to feel the most fatigue.
How Rebecca hit her numbers
Here's everything that Rebecca ate and drank on the day...
Final thoughts
“With better pace management and smarter positioning, I could have started the run in a better spot. Also, if I ate a higher carb intake on the bike, it would have given me more energy to run closer to what I’m capable of.”

“Rebecca enjoyed a successful race at the European Championships, and reported feeling well hydrated throughout. As she works on tolerating more carbohydrate in training, she can increase her fuel intake and hopefully avoid the energy lull and instead run inline with her abilities. ”
Rebecca'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 an adequate level of accuracy in the data collected and the numbers reported. The athlete manages to recall what they ate and drank including most specifics (brands flavours quantities plausible estimations of volumes). However there are estimations made within the data which affect the overall confidence level in the data reported.