First Aid Training

Heat exhaustion
Heat exhaustion occurs when your body gets too hot. The hypothalamus, the part of the brain that controls thirst and hunger, also controls the body’s core temperature. Normally, the body cools itself by sweating. But if you are exposed to high temperatures for a long time (working outdoors in the summer, for example) and don’t replace the fluids you lose, the body systems that regulate temperature become overwhelmed. As a result, your body produces more heat than it can release. Heat exhaustion requires immediate attention because it can progress to heat stroke, a life threatening illness.

Signs and Symptoms:
People with heat exhaustion may experience the following signs and symptoms:
• Heavy sweating
• Fatigue
• Headache
• Pale, clammy skin
• Thirst
• Rapid heartbeat
• Dizziness, fainting
• Nausea, vomiting
• Muscle and abdominal cramps
• Mild temperature elevations

What Causes It?
Heat exhaustion occurs most often when you are exposed to high temperatures and become dehydrated, usually from not drinking enough fluids. It also can happen when large volumes of sweat are replaced with fluids that don’t contain enough salt.

Who’s Most At Risk?

The following factors increase the risk of developing heat exhaustion:
• Being dehydrated
• Age (the elderly and children under 5 years of age)
• Illness or chronic disability
• Obesity
• Pregnancy
• Cardiovascular disease
• Hypertension
• Respiratory disease
• Drinking alcohol
• Physical exertion in hot or humid environments
• Taking medications that interfere with the body’s ability to cool itself, including antipsychotics, tranquilizers, antihistamines, tricyclic antidepressants, beta-blockers, and some over the counter sleeping pills

Treatment
• Rest in a cool environment (a shady spot or, better, an air conditioned room)
• Drink cool (not icy) fluids. Water is usually enough to reverse dehydration. Oral rehydration salts or isotonic drinks will help with salt replacement.
• You can also cool down a casualty who has heat exhaustion by sponging them with cool water or fanning them.

Prevention
If you are working or exercising in the heat, don’t wait until you get thirsty to drink fluids. Instead, drink plenty of fluids before, during, and after the activity. Take the following precautions to prevent heat exhaustion:
• Stay in cool or air conditioned spaces when possible on hot days.
• Drink more fluids than usual. Drinking enough fluids during exercise, for example, helps improve heart function, maintain kidney function, and lower the body’s core temperature. Dehydration can stress the heart and reduce the kidneys’ ability to maintain the correct balance of electrolytes (charged elements — such as potassium, sodium, phosphorous, and chloride — which are essential for the normal function of every cell in the body).
• Check on those vulnerable to heat exhaustion (the elderly, for example).
• Avoid alcohol. Drink water or sports drinks sweetened with natural juices.
• Exercise or work outdoors during cooler times of day.
• Drink 2 cups of water 30 minutes before exercising and drink 1 cup of water every 20 minutes.
• Take cool baths.
• Wear loose, lightweight clothing.
• Long-term prevention of heat exhaustion includes regular, doctor approved exercise. Those who exercise regularly over time, allowing their bodies to adjust to hot conditions, may better tolerate exercise on hot days.

If body temperature goes above 40°c, or if coma or seizure occurs, the casualty may have heat stroke. Heat stroke can quickly lead to heart attack and death if not treated so you should seek medical help immediately.

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