UTS 100M

Mercedes executed a brilliant fueling strategy, sustaining a high carbohydrate intake throughout the gruelling 41+ hour effort. Ahead of the race, she worked with the Sports Science Team to develop a plan that would support her energy levels, reduce the risk of early fatigue from low carbohydrate availability, and still be simple enough to execute. With her crew team across the aid stations, she was able to stick closely to the plan, picking up familiar products at pre-planned intervals and avoiding the need to experiment with anything new on race day.

She started strong, targeting ~90g/h of carbs for the first 15 hours. After that point, however, her intake dipped to ~60g/h, which coincided with a noticeable slowdown. This reflects research suggesting a positive correlation between carb intake and endurance performance. At the 24-hour mark, Mercedes made a smart shift to liquid-only fueling, relying solely on PF Carb Only Drink Mix, as she’d lost the appetite for gels at this point – a common hurdle athletes face during ultra distance events. In the final stretch, she reached for a more unconventional choice - oreos - which delivered a much-needed mental and physical energy boost, helping her dig deep and push to the finish.

It was a great example of how a tried-and-tested strategy, combined with solid crew coordination, can pay off over a race of this magnitude. Maintaining a high carb intake over such an extended duration is no small feat, and this well-thought-out approach clearly played a key role in her successful finish at one of the UK's toughest ultras.

Mercedes approached the race with a clear hydration plan and executed it with confidence. Although she hasn’t yet had a Sweat Test, the relative sodium concentration of the fluids she drank was appropriate for an estimated, average amount. Based on thousands of sweat tests we’ve carried out, the average person loses ~991mg of sodium per litre of sweat, so by drinking PH 1000, Mercedes was likely replacing a solid proportion of her losses. It will be interesting to see her have a Sweat Test going forward to see how close she was to replacing her personal sweat sodium losses.

With support from her crew chief Toby, she was able to quickly refill her soft flasks and get timely advice on how to proceed. This kind of hands-on support from a crew team becomes especially valuable as mental fatigue sets in - a common challenge in ultras - when making clear, effective fueling and hydration decisions gets trickier. Despite the extreme duration and fluctuating weather conditions from warm afternoon hours to the cooler nights, Mercedes was able to titrate her fluid intake effectively with support from her crew. Regular pee stops throughout the event served as a strong and reliable indicator that she was hydrating well and staying on top of her needs.

Mercedes' caffeine intake sat above the usual recommendations, which was sensible given the extreme duration of this race. With a half-life of around 4-5 hours, caffeine’s effects can wear off during such an extended effort, so topping up becomes essential to maintain alertness and focus. Mercedes used a mixture of sources for variety, including PF 30 Caffeine Gels, caffeinated energy shots, and cola to manage her energy levels and help mask fatigue. While research on caffeine use during ultras is still developing, her approach was both practical and well-considered for such a brutal race.