Hyperthermia: Too Hot for Your Health

Irene is retired, she loves to work in her garden. Because she has always spent hours outside, she thinks the heat and humidity of Midwestern summers don't bother her. Then last year an unusual heat wave hit her area. Every day the temperature was over 100° F, and the humidity was at least 90%. Five days into the heat wave, her daughter Kim came over because Irene sounded confused on the phone. Kim found her mom passed out on the kitchen floor. The ambulance came quickly when called, but Irene almost died. She had heat stroke, the most serious form of hyperthermia.

Almost every summer there is a deadly heat wave in some part of the country. Too much heat is not safe for anyone. It is even riskier if you are older or if you have health problems. It is important to get relief from the heat quickly. If not, you might begin to feel confused or faint. Your heart could become stressed, and maybe stop beating.

Your body is always working to keep a balance between how much heat it makes and how much it loses. Your brain is the thermostat. It sends and receives signals to and from parts of your body that affect temperature, such as the spinal cord, muscles, blood vessels, skin, and glands that make substances known as hormones. Too much heat causes sweating. When the sweat dries from your skin, the surface of your body cools and your temperature goes down.

Being hot for too long can cause many illnesses, all grouped under the name hyperthermia (hy-per-ther-mee-uh):

  • Heat cramps are the painful tightening of muscles in your stomach area, arms, or legs. Cramps can result from hard work or exercise. While your body temperature and pulse usually stay normal during heat cramps, your skin may feel moist and cool. Take these cramps as a sign that you are too hot - find a way to cool your body down. Be sure to drink plenty of fluids, but not those containing alcohol or caffeine. For more, please read the Heat Cramps article.
  • Heat edema is a swelling in your ankles and feet when you get hot. Putting your legs up should help. If that doesn't work fairly quickly, check with your doctor.
  • Heat syncope is a sudden dizziness that may come on when you are active in the heat. If you take a form of heart medication known as a beta blocker or are not used to hot weather, you are even more likely to feel faint when in the heat. Putting your legs up and resting in a cool place should make the dizzy feeling go away.
  • Heat exhaustion is a warning that your body can no longer keep itself cool. You might feel thirsty, dizzy, weak, uncoordinated, nauseated, and sweat a lot. Your body temperature stays normal, skin feels cold and clammy. Your pulse can be normal or raised. Resting in a cool place, drinking plenty of fluids, and getting medical care should help you feel better soon. If not, this condition can progress to heat stroke. For more, please read the Heat Exhaustion article.
  • Heat stroke is an emergency - it can be life threatening! You need to get medical help right away. Getting to a cool place is very important, but so is treatment by a doctor. Many people die of heat stroke each year. Older people living in homes or apartments without air conditioning or good airflow are at most risk. So are people who don't drink enough water or those with chronic diseases or alcoholism. For more, please read the Heat Stroke article.

The Signs of Heat Stroke

  • Fainting, possibly the first sign,
  • Body temperature over 104° F,
  • A change in behavior - confusion, being grouchy, acting strangely, or staggering,
  • Dry flushed skin and a strong rapid pulse or a slow weak pulse,
  • Not sweating, despite the heat, acting delirious, or being in a coma.

Who Is at Risk?