Jan 26

Racing In The Heat – Part I

Written by Jesse. Posted in Coaching Thoughts

Racing in the heat can be a challenging task for many athletes with either higher sweat rates, or a poor ability to dissipate heat. This writing explains the approach I like to take for athletes racing these types of events. In fact, this will be a two post topic with this first post covering the pre-race measures any athlete should take. The second post will cover the things you can do on race day to help further mitigate any damage the heat may impose on you.

Here are the preparatory measures that should be taken:

1) First on my list is body composition — you must get down to a body fat that’s optimal for your gender/age. For folks that have too much body fat, they are racing with a 1/8-1/2″ full body sweater. This has a major impact on both heat dissipation ability and sweat rate.

2) Acclimate for the event — for those who live in warm climates, this one is easy. Spend time during your workouts in the sun, and heat the best you can during the 4 weeks leading into the event (minus race week). For those who don’t live in warm climates, you have a couple of options to acclimate before the event and get the sweat rate and blood plasma changes that occur when properly acclimated. The first is to arrive at the event location at least 2 weeks early, and do your final training during the warm part of the day. If you have access to a refractometer, you can test hydration levels each morning and evening to make sure you are hydrating well, and acclimating to your new atmosphere. Another good metric to use in judging your acclimation, is average overnight HR and variability. Take some readings before you head out to your destination, and then compare them to after you arrive. If you can’t arrive at the race location 2 weeks early, a good approach is to layer up and acclimate at home. This requires a solid 2 week period where almost all rides and runs are done “hot” by either turning up the heat at home, or by layering up. Ideally, this is done 4-6 weeks out and is then maintained by continuing once, every other day acclimation sessions through to race day.

3) Last but definitely not least, is to develop and train a solid fueling plan — the first piece of this is to develop a plan based on sound principals. For me, this means a sweat test, to get an idea of fluid losses, and then an assumption based on your previous history (cramping, etc), for sodium content of your sweat. Most athletes fall between 500 and 900 mg per 16oz of sweat loss. With sweat rates at 80 degrees of about 24oz-60oz per hour for most athletes, you can see how quickly the sodium losses add up. Using the fluid losses from your sweat test, the calculated sodium losses, as well as estimated carbohydrate requirements (based on lean body mass), you can put together a feeding schedule to compensate for those losses. This is a topic I can go on about forever, but the biggest take home for hot races is to develop a fueling plan that supplies enough carbohydrate/sodium solution (sport drink) to pee at least once on the bike in half IM, and at least twice in full IM, and then practice that same plan during every single training session for at least 4 months prior to race day. You’d never go into a race without training your metabolic system……You should never going into a race without training your digestive system just as intensely.

My next post will go into those things you can do on race day to help mitigate the heat in addition to the preparatory items above.

-Jesse