Periods of extremely hot weather--heat waves--can cause serious health problems for everyone. In fact, among weather-related events, heat waves are a leading cause of death. Illinois experienced this firsthand in July 1995, when extreme heat contributed to the deaths of more than 700 people in the Chicago area. The following are commonly asked questions about heat-related conditions and how to safely cope with them.

Why do high air temperatures affect the body?

Normally, the body cools itself by sweating. If temperatures and humidity are extremely high, however, sweating is not effective in maintaining the body's normal temperature. When this happens, blood chemistry can change and internal organs--including the brain and kidneys--can be damaged. Heat also can be stressful if the temperature changes suddenly, since it usually takes several days for the body to adjust to heat.

What are some of the most common heat-related conditions?

The most common heat-related conditions are heatstroke, heat exhaustion, heat cramps, sunburn and heat rash. Heatstroke and heat exhaustion are the most serious conditions.

What is heatstroke?

Heatstroke occurs when the body becomes unable to control its temperature: the body's temperature rises rapidly, the sweating mechanism fails and the body is unable to cool down. Body temperature may rise to 106 degrees F or higher within 10 to 15 minutes. Heatstroke can result from overexposure to direct sunlight, with or without physical activity, or to very high indoor temperatures. It can cause death or permanent disability if emergency treatment is not given.

What are the symptoms of heatstroke and how are they treated?

Symptoms of heatstroke include an extremely high body temperature (above 103 degrees F, orally); red, hot and dry skin; rapid pulse; throbbing headache; dizziness; nausea; confusion; and unconsciousness.

If symptoms of heatstroke are present, find a cool place, preferably an air-conditioned indoor setting. Outside, find a spot in the shade. Put the person in a semi-sitting position. Loosen his or her clothing and bathe the head and body with COLD water. Seek medical attention immediately.

What is heat exhaustion?

Heat exhaustion can result when too much time is spent in a very warm environment, resulting in excessive sweating without adequate fluid and electrolyte (salt and minerals) replacement. This can occur either indoors or outdoors, with or without exercise.

What are the symptoms of heat exhaustion and how are they treated?

Symptoms of heat exhaustion may include dizziness, headache, nausea, abdominal cramps, shallow breathing, cool and clammy skin, muscle tremors and heavy perspiration.

A person suffering from heat exhaustion should be moved to an air-conditioned environment if possible. If outside, move the person to a shady spot. Loosen the person's clothing and encourage him or her to drink cool, non-alcoholic, decaffeinated beverages. Keep the person quiet. It may be necessary to seek medical attention if symptoms worsen or last longer than one hour or if the person has heart problems or high blood pressure. If left untreated, heat exhaustion may progress to heatstroke.

How can I avoid heat exhaustion and heatstroke?

Try to keep cool during extremely hot weather. Stay in a cool environment (preferably air conditioned), drink plenty of fluids--such as water, fruit juices or fruit drinks--and use common sense. Heat injury may develop with or without feelings of discomfort.

What if I do not have an air conditioner?

Seek out the nearest facility that is air conditioned, such as a cooling shelter, a senior citizen center, a church, the local YMCA or a center designated by your community. Even short periods of time in a cool environment will lessen the risk of heat injury. Fans alone will not effectively cool an overheated person when air temperatures are above 100 degrees F.

In the wake of the 1995 heat wave in Chicago, many older persons reported being afraid to open windows or to venture out of their homes to go to cooling centers. In these situations, people may want to contact the local police, their church or a community group about being escorted to the nearest cooling center.

What is "plenty of fluids"?

"Plenty of fluids" means at least 1-1/2 to 2 quarts of fluids daily. This can be water, fruit juice, or fruit-flavored or carbonated drinks. Since aging can cause a decreased thirst sensation, elderly persons should drink water, fruit juices or other fruit drinks at regular intervals during the day, even if they do not feel thirsty. Avoid alcoholic beverages and those containing caffeine. Salt tablets are not substitutes for fluids.

What are some good tips on how to avoid heat-related problems?

Use a buddy system. If you are working in the heat, check on coworkers and have someone else do the same for you. If you are at home and are 65 years of age or older or have a chronic health problem, ask a friend, relative or neighbor check on you at least twice a day, even if you have air conditioning. If you know someone who is 65 years of age or older or who has a chronic health problem, check on them at least twice a day.

Limit outdoor activities. Try to plan activities for the coolest times of the day--before noon and in the evening. When physically active, rest frequently in the shade.

Drink plenty of fluids. During hot weather, you will need to drink more liquid than your thirst indicates. Even if you remain indoors and limit your activity, your body still needs to replace lost fluids, salt and minerals. Make an extra effort to drink a minimum of six to eight 8 oz. glasses of cool fluids daily. During heavy exercise in a hot environment, drink two to four glasses of cool fluids each hour. Parents should be sure young children get sufficient fluids. If you are on a special fluid-restricted diet or if you take diuretics, ask your physician about fluid intake during hot weather.

Protect your body. Wear as little clothing as possible when indoors, and wear light colored, loose fitting clothing outdoors. When spending time outdoors, avoid direct sunlight, wear a hat and use a sunscreen with a sun protection factor (SPF) greater than 15 to protect yourself against sunburn.

Never leave children, the elderly or pets in a parked car, not even for just a few minutes.The air temperature inside a car rises rapidly during hot weather and can lead to brain damage or death.

A final reminder--take care of your pets. In many ways, dogs and cats react to hot weather as humans do. Offer pets extra water and be sure to place the water dish in a shaded area if outdoors. Make sure pets have a protected place where they can get away from the sun.