UTMB

A two-hour storm delay meant the race start was delayed until 7.45pm, which impacted how Rachel fueled in the hours leading up to setting off. Her final carb-rich meal fell outside of the ideal 1-4 hour window pre-race to optimise her fuel stores, which likely contributed to her feeling hungry before the race. She sensibly countered this by eating one PF 30 Chew and a final PF 30 Gel before the gun went off.

Across the 22 hours of her UTMB debut, Rachel averaged ~52g/h, marginally above the ~49g/h she consumed across the much longer Cocodona 250 but slightly less than the ~66g/h she sustained for 12 hours at Ultra Trail Chianti Castles earlier this year. Those races allowed her to refine an efficient, individualised fueling strategy for UTMB: PF Carb & Electrolyte Drink Mix in flasks from her crew, PF 90 Gels between aid stations alongside some PF 30 Gels and PF 30 Chews, soda at aid stations, as well as a small amount of real food. Rachel set out carrying enough fuel to reach ~75g/h, knowing that what she actually consumed would depend on the pace she was moving and some of the carbs being left in gel wrappers and flasks (which her crew weighed during the race).

Her working target was 60g/h, which she surpassed between miles 79 and 96, reaching ~65g/h for her strongest fueling section. Her intake then dropped to ~34g/h across the final 2.5 hours when the finish was in sight. This provided some support to see her hold onto second place, but is an area to target in her next 100-miler to make sure the last few hours are as strong as the rest of the day when muscle glycogen will be minimal.

Rachel's fluid intake was consistent across the entire race, totalling over 10 litres of fluid at an average of ~469ml/h and never straying outside 400-500ml/h. This came from two 500ml soft flasks which her crew swapped out at each crewed aid station, and Rachel topped them up with water at uncrewed aid stations. That consistency is a strength and served her well through the cooler overnight hours, but her intake did not flex much as temperatures rose. A ~5.7% drop in bodyweight - beyond the 2-4% dehydration threshold cited to impact performance - tells us she finished in a deficit, and the second half of the race was likely where there was room to drink more as her sweat rate would have been higher. While in a race of this length some mass loss comes from fuel as well as fluid, this deficit is worth addressing by pushing towards the ~700ml/h we have seen her drink during the hotter parts of races this year.

As a salty sweater who’s struggled with hydration issues - including cramping and reported under- and over-doing her sodium intake - Rachel has developed a strategy using PF Carb & Electrolyte Drink Mix and Electrolyte Capsules alongside flasks of plain water. She started strongly, hitting a relative sodium concentration of ~1,349 milligrams of sodium per litre over the opening three hours to Les Contamines, which dipped to ~721mg/L through the long six-hour section to Courmayeur. She then recovered well to ~1,083mg/L and ~1,174mg/L across the middle of the race using a total of 28 Electrolyte Capsules, as well as 2.4L of PF Carb & Electrolyte Drink Mix. Across the full race, this averaged ~948mg/L, below her sweat sodium concentration, but again it was the last section to target as her concentration fell sharply to ~364mg/L, the one section where she did not take her planned Electrolyte Capsules.