Exercise Caution During Summer Workouts

Armen Hareyan's picture

Summer Workouts

Individuals who enjoy outdoor summer workouts should be wary of high heat and humidity.

During strenuous activity, a person's body can generate 15 to 20 times the amount of heat it normally produces. Add high outdoor temperatures and skyrocketing humidity, which slows the evaporation of sweat, and the combination could be deadly.

"The heart works two to four times harder to move blood into the vessels, which dilate as the body heats up," said Dr. Janice Zimmerman, professor of medicine at Baylor College of Medicine. "Exercising in the heat places extra stress on the heart and this can be especially dangerous for those with cardiac conditions."

Exercising in hot weather has also been shown to be less effective. Excessive heat keeps workouts from reaching maximum intensity, which results in less conditioning of the muscles. Overheated tissues are also at greater risk of injury.

Pushing the body too far in extremely hot and humid conditions can lead to cramps, heat exhaustion, heart attack or stroke.

One of the most important tips to remember when taking a workout outdoors is to remain adequately hydrated. Exercisers should drink plenty of water and avoid drinks containing alcohol and caffeine.


According to Zimmerman, a good rule of thumb is to drink more water than you think you will need. Most people, she said, underestimate their body's needs.

To keep summer workouts safe, Zimmerman suggests:

  • Limiting activity between 10 a.m. and 2 p.m., the hottest part of the day.

  • Avoiding or limiting exposure to direct sunlight.

  • Wearing light-colored clothes, which reflect heat more efficiently.

  • Drinking plenty of fluids, before and during the workout.

  • Rising temperatures, however, do not necessarily mean sidelining lunchtime workouts. Decreasing the intensity level or the number of miles being logged can help.

Also, slowly exposing the body to the heat will allow it to adjust. In time, circulation improves, the pulse slows down and sweat glands work overtime to lower the body's temperature. The key, warns Zimmerman, is patience.

"The body is remarkable in that it can adapt to these extreme conditions, but it takes time," she added. "Individuals should begin exercising in the evening or early morning and slowly build up to the middle of the day."