Health Watch -- Heat Tolerance

Health Watch is a Public Service of the Office of News and Publications and is intended to provide general information only and should not replace the advice of a medical professional. You should contact your physician if you have questions about any of these topics.


How do people who have outdoor jobs stand the heat?

If you're used to being indoors in air conditioning, you may wonder how road crews and construction workers can bear to work outdoors in hot weather. Doctors at UT Southwestern Medical Center at Dallas say the key is acclimatization.

That means they've grown accustomed to the hot weather. Dr. Gary Reed, a UT Southwestern internal medicine specialist, says the body learns to adapt to the heat. People who work in hot weather frequently get used to it and can tolerate higher temperatures than people who stay indoors most of the time. That's also why you hear about more deaths from heat stroke when a heat wave strikes areas that aren't usually hot. If you live in an area where the temperatures gradually get warmer over time, your body learns to adjust to the heat. But if it suddenly gets much hotter than usual, the body doesn't have time to adapt.

Dr. Reed says humidity is also a factor. High humidity with heat and very little wind movement can create dangerous conditions. It's harder for the body's cooling mechanisms to work. The body cools itself by sweating and letting air evaporate the sweat, but in hot, humid, still conditions, the sweat can't evaporate.

Whether or not you're accustomed to the heat, you need to drink plenty of liquids in hot weather. Use fans to stir the air and help cool you. If you're not used to being outdoors in the heat, don't try to jump into activities requiring physical exertion.

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May 2004

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