Heat exhaustion is a warning that your body is becoming overheated. Signs of heat exhaustion include heavy sweating, paleness, muscle cramps, fatigue, dizziness, headache, nausea or vomiting, and fainting. If you don't get help, you may get heat stroke. Heat stroke is also called sunstroke. It is a medical emergency that is often fatal. It occurs when your body can't control its temperature by normal cooling mechanisms such as sweating. Your body temperature may rise to 106 degrees F (41 degrees C) or higher. Symptoms of heat stroke include high body temperature, dry skin (no sweating), rapid pulse, headache, nausea, altered mental status, seizures, and unconsciousness. Get medical help right away if someone has these symptoms.

Older adults can be at risk for heat-related illness at lower temperatures, particularly if the air is humid. High humidity makes it harder for sweat to evaporate from the body. If the temperature is 90 degrees, for instance, and the relative humidity is 70%, the air feels as though it’s 106 degrees. If you’re standing in full sun, it would feel as though the temperature were 121 degrees.

You are at higher risk of developing heat-related illness if you’re following a salt-restricted diet because of high blood pressure. Don’t take salt pills without checking with your doctor. Older adults taking multiple medicines also are at higher risk for heat-related illness. This is especially true for water pills (diuretics). It’s important to drink extra fluids during hot weather, but ask your doctor if you need to watch how much you drink and how much is safe.

A person who is overweight has more difficulty regulating body temperature than someone of normal weight. An overweight person also retains more body heat.

Although fans and air conditioners work best, if you don't have either, you can still take steps to keep cool. Open windows at night to let cool air in. If possible, open windows on two sides of the house to allow a cross-flow of air. Keep blinds, drapes, or shades pulled during the hottest part of the day. Take a cool shower or bath.

Also check out shopping malls and movie theaters. If you don't have transportation, your local senior citizen center or agency on aging may be able to help.

Older adults often have poor circulation, and their sweat glands don't work as well as they did. Stick with lightweight, loose-fitting cotton clothing. Light-colored clothing also helps because it will reflect some of the sun’s heat. Also wear a wide-brimmed hat to keep the sun off your face.

Symptoms of heat fatigue include cool, moist skin and a weak pulse. Symptoms of heat exhaustion include a lot of sweating, giddiness, and cold, clammy skin. The pulse is normal or increased.

If possible, also have the person lie down and rest. Offer the person cool water or fruit juice. Don't give the person beverages that contain caffeine or alcohol. Sponging off with cool water will also ease symptoms.