Hot Weather: Understanding and Preventing Heat-Related Illnesses

Hot weather can cause heat-related illness which ranges in severity from relatively mild heat cramps to life-threatening heat stroke. Among weather-related events, periods of extremely hot weather, known as heat waves, are a leading cause of death. Illinois experienced this first-hand in July, 1995 when a heat wave contributed to more than 700 deaths in the Chicago area. Here we address commonly asked questions about hot weather, heat-related illnesses and provide information on how to safely cope with these conditions.

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

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.

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. Heatstroke can result from prolonged exposure to high temperature. It can cause death or permanent disability if emergency treatment is not given.

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

If symptoms of heatstroke are present, seek medical attention immediately. Find a cool place, preferably an air-conditioned indoor setting. If outside, find a spot in the shade. Put the person in a semi-sitting position. Loosen clothing and bathe the head and body with COLD water. Do not give fluids.

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.

Symptoms of heat exhaustion may include dizziness, headache, nausea, abdominal cramps, shallow breathing, cool and clammy skin, muscle tremors and heavy perspiration. Body temperature will be near normal.

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. 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.

Try to keep cool during extremely hot weather. Stay in a cool environment (preferably air conditioned), avoid exercising outdoors, 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.

Seek out the nearest facility that is air conditioned, such as a designated cooling center. 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 90° 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.

"Plenty of fluids" means at least 1½ to 2 quarts of fluids daily. Since aging can cause a decreased thirst sensation, older adults should drink at regular intervals, even if they do not feel thirsty. Avoid alcoholic beverages and those containing caffeine. Salt tablets are not substitutes for fluids.

Anyone can develop heat-related illnesses. However, certain groups of people are at increased risk during extremely hot weather. These include people who work outside, elderly persons living alone, people with chronic medical conditions, and persons taking certain medications.

A number of different kinds of medications can pose problems during periods of extremely hot weather. These include diuretics (water pills), many heart medicines, diabetes medicines (tablets and insulin), psychoactive drugs (antidepressants and mood altering drugs), antihistamines (hay fever and allergy medicine) and antihypertensive (high blood pressure) drugs. Do not change or discontinue prescribed medications without advice from your physician.

Yes. Young children, particularly infants, are extremely sensitive to heat and can easily become dehydrated (lose more body fluids than usual) from high air temperatures. To help avoid dehydration during extremely hot weather, children should drink plenty of fluids. Young children should be kept out of direct sunlight.

• Ensure that students are well hydrated. Plain water is the liquid of choice, with sports drinks and diluted fruit juice acceptable forms of fluid replacement.
• Encourage students to wear loose fitting summer clothing.
• In order to prevent heat fatigue, offer regularly scheduled rest periods.
• Allow students to utilize alternative areas located on the lower or ground level of the school or shady areas on the school grounds.
• Encourage the school district to establish both a policy and a plan to deal with extreme temperatures.
• Age-appropriate prevention education regarding heat-related illnesses should be made available for all students, parents and staff.

• 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 to 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 — in the early morning 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. 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 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. Offer pets extra water and place the water dish in a shaded area, if outdoors. Make sure pets have a place where they can get away from the sun.

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• Building Resilience Against Climate Change (BRACE) Illinois
• CDC: Extreme Heat
• Keep Cool Illinois
• National Weather Service

• Hot Weather Advisory
• A Summer Survival Guide
• Excessive Heat Events Guidebook