Andy Blow
ÖTILLÖ Swimrun World Championship
SandhamnTop 50Andy's headline numbers
Andy's strategy
Fueling
T - 1-4hrs: Ate a carb rich meal (Low in fat & fibre)
Andy would benefit from taking in a final dose of carb <30 minutes before
"I had solid energy nearly all day."
Andy got up at 3:40am on race morning to allow plenty of time for his pre-race meal and a stress-free arrival ahead of the 6am start. After a sizable carb-rich breakfast, he felt quite full and opted to skip the pre-race PF 30 Gel we typically recommend around 15 minutes before the gun. While swimrun does include aid stations, it still presents unique logistical challenges. It’s hard to carry much fuel when you’re just in a wetsuit, so planning becomes even *more* important. Despite this, Andy managed to take on an impressive ~692g of carbohydrate across the 24 run sections (totalling ~60km) and 23 swim sections (~9.1km). That works out to an average intake of ~78g of carb per hour - an increase of ~23g/h compared to his last outing at the swimrun World Championships. To achieve this, he carried four PF 90 Gels, one PF 30 Gel, three PF 30 Caffeine Gels, one PF 30 Chew, and also picked up additional gels plus a few pieces of chocolate at the on-course aid stations, successfully fueling his efforts and mitigating flavour fatigue.
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.
Andy1800mg/L
Andy has been Sweat Tested to dial in his 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.
Given Andy's losses are Very High (1,800mg/L), nailing his hydration strategy remains important, even when it's Mild.
Learn moreT - 60mins: Drank ~500ml of strong electrolyte drink
"I didn’t nail my hydration but it was not too bad."
Andy’s high sweat sodium concentration (~1,800mg/L) and sweat rate both make him prone to cramping and hydration issues. To manage this, he carried two PH 500ml Soft Flasks, each with a PH 1500 (Drink Mix) sachet, topping them up with water at an early aid station. He supplemented with nine Electrolyte Capsules, taking in a total of ~3L of fluid at a relative sodium concentration of ~1,315mg/L. However, his hydration strategy was limited by the availability of aid stations and the inability to drink while swimming. Even though his total fluid and sodium intake was decent, it was still lower than during his 2019 race, and by the end, he began to experience cramping in his hamstrings and lower legs, worsening as he continued on. This may have been due to a fluid and electrolyte imbalance, but also likely reflects a lack of race-specific conditioning given his late entry. A sodium preload and a more proactive hydration strategy with greater reliance on Electrolyte Capsules could help align his intake with his losses next time.
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
Andy is a frequent caffeine user, and called upon the performance boosting capabilities of the stimulant during this race. In total, he took ~500mg of caffeine, averaging ~6.9mg per kilogram of bodyweight, which is slightly higher than the 3-6mg/kg the scientific literature would recommend. With his high tolerance, he didn’t have any negative side effects and was therefore likely within his individual tolerances and an appropriate strategy.
How Andy hit his numbers
Here's everything that Andy ate and drank on the day...
Final thoughts
“I couldn’t have gone much better, and for certain, the increase in carbohydrate intake compared to last time was the most significant differentiator for me, which led to a better performance in the second half of the race.”
“Andy had a strong race, thanks to his well-structured plan and commitment to fueling as much as he could. A slight increase in electrolyte intake from the start could help eliminate the dehydration-related symptoms that surfaced in the later stages.”
PF&HAndy'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 good confidence in the accuracy of the data reported. An athlete feels that the numbers closely reflect what they consumed despite a couple of estimations which may carry some degree of error. The majority of what was consumed is recorded to a high level of specificity (most volumes are known through the use of bottles brands quantities flavours). The numbers are very plausible and align with previous data recordings (if an athlete has collected data previously).