In some cases, a person's temperature can get too high, too quickly. And when that happens, serious heat illness can set in.
One thing that can interfere with the bodies' ability to regulate temperature: not drinking enough water.
"If you are a diabetic, have high blood pressure or are taking water pills you are at a much higher risk of having dehydration problems because you are already turning out water a lot more than ordinary people are," said sports medicine specialist Dr. Clarence Shields.
Then there's something that often can't be avoided -- repeatedly going in and out of air conditioned buildings.
"You have to monitor your fluid intake when you change environments because you will get a false sense that you are not sweating, or that your body has adjusted to it," said Dr. Shields. "Your body can control things if the temperature stays the same. When you switch it you can sometimes trick your body."
When your body temperature gets too high it can lead to serious heat illness, like heat stroke, heat exhaustion and heat cramps.
Some of the warning signs for heat stroke are: red, hot and dry skin, fast and strong pulse, dizziness, throbbing headache and confusion.
Heat exhaustion is a milder form and unlike heat stroke, skin is usually moist and cool. Other heat exhaustion signs are: heavy sweating, paleness, muscle cramps, and headache.
Experts say some good ways to cool down from heat exhaustion are to rest, take a cool shower or bath, and drink something cool, that's non-alcoholic. And you don't need anything fancy.
"You don't have to have the Vitamin Water with minerals in," said Dr. Shields. "You can just drink regular water."