Dry Heat vs. Humid Heat

The old saying, "It's not the heat, it's the humidity," is true. In fact, humid heat is worse for us than dry heat. This is because humidity interferes with our body’s temperature regulating mechanism.

Our body can tolerate only slight increases in internal temperature. When the temperature is very hot outside, the body's regulating mechanism prevents heat from building up by releasing the heat from the surface of the skin through the evaporation of sweat.

While exercising in hot, dry weather, it is possible to lose as much as 3 quarts of body fluid in one hour of strenuous exercise. This fluid must be replenished; otherwise, dehydration occurs.

On the other hand, humid heat does not allow sweat to evaporate from the skin. This makes a person stay hot longer and prevents the body from cooling down quickly. In extreme cases, this can cause damage to the brain or other vital organs.

Resources:

Read some advice from the American Council on Exercise about exercising when the weather is hot.

Seniors are especially susceptable to severe health problems often caused by hot weather. The National Institute on Aging highlights certain health and lifestyle risk factors to look out for.

Dogs, cats, and other animals can suffer from the same hot weather problems that affect humans: overheating, dehydration and even sunburn. The ASPCA suggests ways for pet owners to keep Spot and Fluffy cool and healthy.

August 9, 2003