The human body is cooled naturally when heat escapes from the skin and when sweat evaporates from the skin. Hot, sticky summertime weather, however, can overtax the body’s natural cooling system and cause heat-related illnesses. These illnesses can be quite serious, causing cramps, dizziness, headaches, nausea and vomiting, and even death.

The Medical Society of the State of New York cautions that although anyone can suffer from a heat-related illness, some people are at greater risk. Those at high risk include the very young and the very old and those who are physically ill, especially those with heart disease or high blood pressure. The best defense is prevention and the key points to remember are to drink plenty of fluids and to stay as cool as possible.

Tips for preventing heat-related illness:

To prevent heat-related illnesses, the medical society recommends the following tips, adapted from those of the Centers for Disease Control and Prevention.

Drink plenty of water or other nonalcoholic fluids and do not wait until you are thirsty before drinking. Thirst is a sign that the body is dehydrated and, as a result, is not working at its peak efficiency. Common signs of dehydration include dry lips, mouth and skin; nausea; dark colored urine or infrequent urination; constipation; increased body temperature and labored breathing. Warning: If your doctor generally limits the amount of fluid you drink or has prescribed water pills, ask your doctor how much you should drink while the weather is hot.

Do not drink liquids that contain caffeine, alcohol or large amounts of sugar. These beverages actually make the body lose fluid. Also, avoid very cold drinks because they can cause stomach cramps.

Stay indoors and, if at all possible, stay in an air-conditioned place. If your home does not have air conditioning, go to the shopping mall, library or other cool public space. Even a few hours spent in air conditioning can help the body stay cooler when you go back into the heat. Call your local health department to see if there are any heat-relief shelters in the area.

Electric fans may provide comfort, but when the temperature is in the high 90s, fans will not prevent heat-related illness. Taking a cool shower or bath, or moving to an air-conditioned place, is a much better way to cool off.

Wear lightweight, light-colored, loose-fitting clothing.

Never leave anyone in a closed, parked vehicle.

Visit adults at risk at least twice a day and closely watch them for signs of heat exhaustion or heat stroke. Infants and young children need even closer watching.

If you must be out in the heat, limit outdoor activity to morning and evening hours.

Cut down on exercise. If you must exercise, drink two to four glasses of cool, nonalcoholic fluids each hour. A sports beverage can replace the salt and minerals you lose in sweat. Warning: If you are on a low-salt diet, talk with your doctor before drinking a sports beverage.

Try to rest often in shady areas.

Protect yourself from the sun by wearing a wide-brimmed hat (which also keeps you cooler) and sunglasses and by putting on sunscreen of SPF 15 or higher. The most effective products say “broad spectrum” or “UVA/UVB protection” on their labels.