Training in Heat to Improve Performance

A paper from the University of Oregon shows that training in the heat can improve racing performance in the cold (Journal of Applied Physiology, October 2010). Twenty competitive cyclists continued their regular training. In addition, they completed ten 1.5-hour training sessions at 50 percent of their maximum effort (VO2max). However one group rode in a lab heated to 104 degrees, the other group rode in 55 degree lab.

The cyclists who were heat acclimated improved their time-trial performance four to eight percent, while the cold-trained group did not improve.

Training in the heat makes you a better athlete because it cools your body better. Since more than 70 percent of the energy used to drive your muscles is lost as heat, the harder you exercise, the more heat you generate and your body temperature rises. With each increase in body temperature, your body requires more oxygen to turn food to energy. Since lack of oxygen is the limiting factor to how fast you move and how much power your muscles generate, any increase in body temperature slows you down.

Training in the heat increases blood volume so you have more blood available to carry heat from hot muscles to your skin where the heat can be dissipated. sweating begins earlier and is more profuse to cool your skin, and the heart pumps hot blood to the skin faster. All these factors lower body temperature.

Some athletes may decide to heat train by wearing plastic or thermal suits. It could be dangerous because it prevents sweat from evaporating and a person could overheat and pass out or even die. You can help protect yourself from heat stroke by knowing the progressive signs of rising body temperature. See my report on the dangers of swimming in warm water