Western States® 100-Mile Endurance Run

During the 2025 Western States® 100 (WSER), most of Chris’ carbohydrate intake came from gel-based products (PF 90 Gel, PF 300 Flow Gel, PF 30 Gel), supported by some PF Carb & Electrolyte Drink Mix to help meet his hourly targets. This reflects a common trend among elite-level athletes, who increasingly favour sports nutrition products over ‘real food’ during races. While whole foods offer variety and can help avoid ‘flavour fatigue’, they tend to carry higher digestive demands due to the mix of macronutrients. In comparison, gels and drink mixes deliver consistent, fast-absorbing fuel with a lower risk of GI issues under race stress. Chris has practiced and trained his gut extensively to ensure this wouldn’t affect him on race day.

While Chris didn’t completely separate his fuel from his hydration (his bottles did contain some carb-based drink mix) his primary fuel still came from gels. This approach gave him better control over his intake, ensuring he could manage his carbs and fluids in parallel without relying entirely on one to deliver both. In contrast, athletes who depend solely on high-carb fluids risk underfueling or dehydration when fluid consumption drops. Chris’s strategy offered flexibility and consistency, which proved critical given the heat and demands of WSER.

Higher-carb intakes are becoming increasingly popular among professional athletes to support performance in endurance events. In 2024, Chris averaged ~94g/h at Western States, finishing 10th. This year, he increased that to ~126g/h, taking second place and just over an hour off his previous time. In a race like this, that’s a huge achievement and was unlikely to be a result of increased fitness and training alone. His fueling helped him maintain a fast pace deep into the race, including a strong final mile despite obvious muscular fatigue. His hourly intake ranged from ~95g/h during the early stages of the race, and peaked at ~196g/h in shorter segments where crewed aid stations were more frequent, reflecting smart adjustments: higher intake when conditions allowed, lower during longer, hotter climbs where GI tolerance may be decreased and the capacity to carry more fuel was limited. Compared to 2024, Chris’ strategy in 2025 was more aggressive, but well-tolerated and effective for his goals.

The Western States course is famous for its heat, climbs, and demanding conditions that tested Chris’s hydration strategy. With ambient temperatures ranging from 5°C on the start line in the early hours, to highs near 37°C, Chris’s sweat rate will have varied across segments of the race. After spending some time in the Precision Performance Lab to understand his individual fluid losses in extreme conditions similar to this, Chris learnt that although his sweat sodium concentration isn’t particularly high compared to the average athlete, as a result of his high sweat rate, he would have to be proactive with both his fluid intake and sodium replacement to avoid accumulating sodium loss which would contribute to the cramping he has previously suffered from when racing.

Chris drank nearly 16 liters of fluid over the race; an aggressive and appropriate approach given the environmental demands and his high sweat rate. His strategic use of 46(!) Electrolyte Capsules at intervals throughout the race helped replace the sodium he was sweating out, particularly at points where his plain water intake increased at the on-course, unsupported aid stations. As recommended by the Sports Science Team he used cooling tactics (like ice in his sleeves and pack, and dousing of water wherever possible) to offload some thermal strain. This was a critical addition to his strategy that his crew were prepped for and that reduced dehydration risk through sweat rate modulation. While he admitted to not finishing every bottle, this was counteracted by proactive planning, drinking at aid stations, and drinking to thirst.

Caffeine played a key role in Chris’ race to support his energy levels. His caffeine intake of ~5.8mg/kg of body weight, sits well within the performance-enhancing range (3-6mg/kg). Since Chris doesn’t use caffeine gels due to personal preference, he relied solely on flat, caffeinated energy drinks, taken only at crewed aid stations because he understands the performance benefits the stimulant has to offer. These were timed strategically, with more concentrated intake in the middle and later stages of the race where fatigue began to accumulate.

This approach matches what’s now understood about how caffeine works in long events. It doesn’t just reduce effort perception, but also helps with mental fatigue, muscle activation, and staying focused. Chris mentioned needing “a lot of mental energy” towards the end, and the caffeine likely helped him keep going despite fatigue. Spacing out the doses also helped him to reduce the risk of GI issues and provided a change from the electrolyte drinks and water he was otherwise taking, helping to avoid flavour fatigue.