IRONMAN® Cairns

Luke reached the highest carbohydrate intake we have seen him consume yet (with prior races being in ~57-65g/h range) with the help of a PF 300 Flow Gel bottle on the bike, alongside four PF 30 Caffeine Gels, and a combination of caffeinated and ‘regular’ gels on the run. This allowed him to hit ~20g/h more compared to this exact race in Cairns two years prior. To do this, Luke has undertaken extensive gut training, working on increasing his gut’s tolerance to higher carb levels and greater fluid volumes, particularly when ‘frontloading’ the bike with over ~110g/h before dropping down, closer to ~50g/h on the run.

With a history of severe hydration-related issues occurring in prior races due to his extremely high sweat sodium concentration and high sweat rate, Luke once again followed a relatively aggressive fluid and electrolyte replacement strategy. After varying success with strategies in the past (including a sub-par performance at the World Champs in Nice last year), Luke made a couple of significant changes in Cairns; notably modifying the volume of fluid taken in following more detailed sweat rate measurement and introducing the use of sodium chloride tablets. Due to Luke’s high sweat rate and extremely high sweat sodium concentration, he loses greater amounts of chloride than many other people and, in addition to sodium, it was hypothesised that this extreme loss of chloride may have been causing some acid/base balance issues in his blood. Based on sweat loss modelling, Luke targeted a slightly more ‘conservative’ than typical fluid intake on the bike (~1L/h) to match the environmental conditions and his intensity. Alongside this, he used a mixture of sodium chloride tablets, PH 1500 and Electrolyte Capsules to ensure that adequate chloride was being replaced along with sodium. This approach appears to have been successful as Luke felt this was the best execution of a hydration strategy to date. Race stats and further subjective feedback agree as he experienced no cramping (common in past races), peed once, experienced minimal amounts of swelling and ended with a sub-9 hour race performance.

Luke has a high tolerance for caffeine, having previously surpassed the general caffeine recommendations on multiple occasions. This race was no different. Consuming six caffeine gels during the race and one in the final 15 minutes pre-race, Luke consumed double the upper limit which current guidelines recommend for a single dose for performance enhancement. Considering the guidelines target shorter duration events than this, it’s not necessarily a bad thing for him to take above 6mg/kg, however, such high doses (although spread out) may come with a greater risk of associated negative side effects. For most people, staying within the 3-6mg/kg guidelines remains the recommended course of action.