London Marathon

In the move up to marathon-distance races from 10km (6.2 miles) events, Mhairi implemented consistent fueling in her longer, higher intensity sessions (including a half marathon) to get accustomed to taking on and tolerating gels and carbohydrate drinks at a fast pace. With this gut training under her belt, Mhairi used a well-considered fueling strategy in London to reach her target of over 75g per hour. She picked up seven of her eight bottles of PF Carb & Electrolyte Drink Mix at the pro aid stations, as well as consumed four PF 30 Gels throughout the race. She was able to make up for one missed bottle and gel on route by sipping some of a friendly pacer’s bottle and having an extra PF 30 Gel she’d carried as a back-up.

Mhairi sipped on her PF Carb & Electrolyte Drink Mix bottles throughout the race to replace both the fluid and sodium she was losing in her sweat. Given the mild conditions and marathon distance, the relatively low volume and moderate relative sodium concentration she consumed would’ve been sufficient to avoid too large a level of dehydration. She did notice some twinges of cramp in her calf in the last 2km (1.2 miles), but put this down to the extremely fast pace at the beginning of the race rather than anything hydration related. A Sweat Test and sweat rate data collection would help to understand her sweat losses in more detail and give her full confidence in her strategy for future races.

After practising with PF 30 Caffeine Gels in training, Mhairi knew she tolerates the stimulant well. So, she took one PF 30 Caffeine Gel within the final 20 minutes pre-race, followed by one just over an hour in and another over 2 hours in. This met the general caffeine recommendations for someone of her body weight, but she could look to take her last caffeine dose slightly earlier, as it takes ~45 minutes for it to peak in the bloodstream, to maximise her chances of experiencing the perceived energy boost.