Brett King
IRONMAN® World Championships
Brett's headline numbers
Brett's strategy
Fueling
Carbohydrate is the main fuel you burn when racing. Failing to fuel properly is a leading cause of underperformance in longer races.
Brett based his fuel strategy around using a PF 300 Flow Gel and PF 30 Chews in order to shoot for ~120g of carb per hour for the bike. While this is above our recommendations for carbohydrate intake for a race of this intensity and duration, he reduced his intake through the run to a lower ~73g/h. This ‘front-loading’ of carb intake is a tactic we commonly see triathletes use as it’s often easier to get more fuel in on the bike than the run. Brett had practiced with high carbohydrate intakes during training in the months before racing in Hawaii. A key aspect of tolerating higher levels of carb intake is being able to handle high amounts of fructose. Since we typically consume limited amounts of fructose in our diets, the upregulation of fructose transporters, more so than glucose transporters is a key factor for improving gastrointestinal absorption. This makes it especially important to practice with fructose-based carbohydrates. Brett comfortably tolerated his high intake and was delighted with how he executed his strategy on the day.
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.
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.
Given Brett’s losses are High (1,290mg/L), nailing his hydration strategy becomes especially crucial when it’s hot and/or humid.
Learn moreBrett was conscious that he hadn’t performed so well in the heat on previous occasions, so he took a Sweat Test to take the guesswork out of figuring out how much sodium to replace. After the Sweat Test revealed that he’s a ‘salty sweater’ (he loses 1,290mg of sodium per litre of sweat), he proactively aimed to replace a decent proportion of his sweat sodium losses primarily with PH 1500 (Tablets) and Electrolyte Capsules. At one point, Brett dropped one of his bottles with his pre-prepared carb and electrolyte mixture. He knew that missing that additional fluid, carbs and sodium would mean he wouldn’t reach his targets, so he adapted impressively ‘on the fly’ and picked up a bottle of on-course hydration to ensure he was able to get closer to his planned intake.
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.
Brett didn’t report using any caffeine directly in the race apart from his morning coffee. Data shows promising benefits of caffeine use for performance, so he should consider trialling caffeine in future races to see if it indeed works for him.
How Brett hit his numbers
Here's everything that Brett ate and drank on the day...
Brett's weapons of choice
Final thoughts
PF&HBrett's full stats
Data Confidence?
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.