Heat and Exercise: Grin and Bear it

4,000 women ran in the New York Mini, a 10k race. The winning time of 32 minutes and 43 seconds was the slowest time recorded in ten years.

The Eagle Man Half Ironman had 1,400 participants who competed in a 1.2 mile swim, a 56 mile bike ride and a 13.1 mile run. Recorded times were slower than normal. In another event, the Philadelphia International Championship, a 156 mile bike race, half of the competitors dropped out. In this race, the winning time of 6:14:47 was about 30 minutes slower than last year's race. Are athletes for some reason in worse shape now than they were as recently as a year ago? Is there some mysterious force which is preventing them from performing optimally?

The mysterious force is heat. All three of these events were hotter than previous races, and extreme heat can definitely impact performance.

Heat and Cooling the Body

The muscles need blood pumped to them, however on humid days, the skin needs more blood pumped to it, in order to accomplish the process of sweating – cooling you off. The heart works harder as it must pump more blood than normal. More blood to the skin means less blood to the muscles. Also, when the body temperature rises, glycogen stores are depleted more rapidly, leading to decreased performance, cramping, etc.

Research on Heat

U.S. Army Researchers Scott Montain and Matthew Ely researched seven marathons and compared performance on years where the temperature was different and the same course was used. Their research showed that an elite level runner who could run a marathon in three hours on a cooler day would be twelve percent slower in the heat. Runners have tried carious things to combat this, such as pouring water over themselves prior to a race, which according to Army researchers can be bad for the runner. "Sweat must evaporate to provide cooling," says Samuel N. Cheuvront, an Army researcher, "dripping does not help." Getting your body too wet can block the pores and prevent you from sweating, making the body even hotter.

How to Deal with Heat

One way to deal with the heat is to just avoid it. By exercising when it's cooler – early in the morning, for example – the body is better able to function better.

Another way, according to the Army's research, may just be to grin and bear it. Their studies reported that people adapt to heat over short periods of time. They conducted a study on heat acclimation – participants were asked to walk on a treadmill inside of a room that was 100 degrees. On the first day, the average participant only lasted 30 – 45 minutes. By day five, however, participants last 100 minutes easily.

Exercise caution when working out in the heat and stay hydrated. If you feel discomfort or short of breath, stop exercising and cool off in the shade.

The elements can hinder our workouts and performance, but with common sense, we can safely overcome these obstacles and enjoy our workouts.

Still too hot to workout outside? Check out our exercise videos and yoga videos.