• As a triathlete who exhibits extreme sweat sodium and fluid losses, age grouper Luke Henderson pushed himself to the limit once again by competing in IRONMAN Cairns in hot conditions (~24℃/75°F)
• After experiencing severe cramping and hyponatremia in the past, Luke has put together a more proactive hydration strategy with the help of the PF&H Team. Being more aggressive with his sodium and fluid replacement proved successful at IM Western Australia and IM 70.3 Melbourne, and going into another full distance race Luke looked to apply a similar strategy again
• With good intentions, Luke made some changes on the run, opting to use more Electrolyte Capsules than previous races in replacement of the PH 1500 mixes he’s used before. Unfortunately, this adjustment proved not to be as effective and resulted in him not feeling great towards the end of the race
• Nevertheless, Luke put in a decent performance that saw him finish 8th in the M35-39 age group with a solid time of 9 hours and 25 minutes

Hydration

• As has become the norm for Luke, he preloaded ahead of the race by drinking two PH 1500 (Tablets) in ~750ml/24oz of water; a drink with a relative sodium concentration of 2000mg/L. This strategy is to ensure that he starts well hydrated in preparation for the extremely high sweat losses he is going to incur
• During the five-hour bike leg, Luke premixed six ~620ml/21oz bottles with three PH 1500 (Tablets) in each which he drank interchangeably with bottles of plain water picked up at aid stations
• Luke drank a total of ~6.2L/210oz during the bike, made up of ~3.7L/125oz of concentrated PH 1500 and ~2.5L/85oz of plain water, which equated to ~1.2L/41oz of fluid per hour
• This is a high fluid intake, though not necessarily for Luke who we know has a sweat rate of >1.5L/h (51oz/h), and has previous experience drinking ~1.4L/h (47oz/h) at Western Australia. Remarkably, he actually drank over one litre (32oz) less plain water than he had intended to drink but conditions were slightly cooler than anticipated
• Luke consumed an average of ~2,703mg/h sodium on the bike which equates to a relative sodium concentration of ~2,202mg/L. This would be a very high concentration of sodium for most athletes but Luke falls at the extreme end of fluid and sodium losses, possessing a very high sweat sodium concentration of ~2,129mg/L. So, this was an effective strategy to replace his losses and is similar to the concentration he had overall at the shorter IM 70.3 Melbourne
• The run leg was where Luke adjusted the plan he implemented at IM Western Australia. He stuck to his aggressive sodium and fluid targets, but this time Luke solely used Electrolyte Capsules alongside water he picked up instead of meeting his sodium needs using some flasks of PH 1500
• Using this strategy, Luke worked on a rigid rotation of four Electrolyte Capsules every other aid station, consuming 48 Electrolyte Capsules in total. This equates to an intake of 12,000mg of sodium and 6,000mg of potassium, which he had intended to have alongside ~6L/203oz of water to make a relative sodium concentration of ~2000mg/L. However, Luke didn’t not drink this very high volume of fluid during the run leg, estimating that he actually drank closer to ~3.6L/122oz of plain water, which therefore made the relative sodium concentration of his intake an extremely concentrated ~3372mg/L
• Around one hour into the run, Luke started to get a “tingling sensation” in his hands, face and upper body. Whether this is directly linked to him consuming such a large quantity of electrolyte capsules without a sufficiently high volume of water to match is not completely clear. However, taking on such an extreme concentrations of both sodium and potassium can certainly cause the body to take fluid from other areas to dilute blood plasma which can lead to severe issues (learn more)
• Reflecting on the race, Luke knew what he had done wrong, saying “I was a little too confident that I had everything dialled in so I didn’t monitor things as closely during the race as I should have”. Considering he took on less fluid than he had planned, Luke should have reduced the number of Electrolyte Capsules he was consuming to keep the relative sodium and potassium concentration to a more reasonable level; this is especially important for someone like Luke who is working with such high intake quantities to avoid issues to his health as well as performance

Fueling

Conclusions

• Luke had a tough run at IM Cairns after taking on a very high sodium quantity which resulted in an immensely strong relative sodium concentration, a consequence of drinking less fluid than he had intended and not being flexible with his planned consumption of Electrolyte Capsules
• He pushed through “not feeling great” to finish 8th, a brilliant performance in warm conditions all things considered
• Going forward, Luke would benefit from being more flexible during the race so he can adjust his plan on the fly while being conscious of the quantities of fluid, sodium and carb he is taking on board. This is particularly important for an athlete like Luke, who is working with such large losses and intake volumes