Heat Exhaustion: Causes, Symptoms and Treatment

Heat exhaustion is a condition whose symptoms can include profuse sweating and rapid heartbeat due to the excessive increase in body temperature. It is one of three heat-related syndromes; heat cramps are the mildest and heatstroke the most severe.

The causes of heat exhaustion are exposure to high temperatures, especially combined with high humidity and intense physical activity. If not treated immediately, heat exhaustion can lead to heat stroke, a life-threatening condition. Fortunately, heat exhaustion can be avoided.

Signs and symptoms of heat exhaustion can come on suddenly or over time, especially with prolonged periods of exercise. Possible signs and symptoms of heat exhaustion include:

Cold, clammy skin with goosebumps when exposed to heat Profuse sweating Fainting Dizziness Fatigue Weak and rapid pulse Low blood pressure when standing Muscle cramps Nausea Headache

If you think you have heat stroke:

Suspend all activities and rest Find a cooler place Drink cold water or sports drinks

Consult your doctor if signs and symptoms worsen or do not improve within an hour. If you are with someone showing signs of heat exhaustion, seek medical attention immediately if they become confused or agitated, lose consciousness, or are unable to drink fluids. You will need to cool your body immediately and seek emergency medical attention if your core body temperature (taken with a rectal thermometer) reaches 40°C (104°F) or higher.

If you need medical attention for heat exhaustion, it may be obvious to medical staff that you have it, but they may also take your rectal temperature to confirm the diagnosis and rule out heat stroke. If doctors suspect heat exhaustion has led to heat stroke, you may need to have additional tests, such as:

A blood test

to check for low sodium or potassium in the blood, as well as blood gas

a urinalysis

to check the concentration and composition of urine and to check kidney function, which can be affected by heat stroke

muscle function tests

to check for rhabdomyolysis (severe damage to muscle tissue)

X-rays and other imaging tests

to check for injuries to internal organs

In most cases, you can treat heat exhaustion yourself by doing the following:

Rest in a cool place.

Ideally, you should enter an air-conditioned building, but at the very least find a shaded area or sit in front of a fan. Lie on your back with your legs elevated above the level of your heart.

Drink cold liquids.

Drink water or sports drinks. Avoid drinking alcoholic beverages as they can contribute to dehydration.

Try cooling measures.

If possible, take a cool shower or bath or place wet towels on your skin. If you are outdoors and away from shelter, soaking in a cool pond or stream can help cool you down.

Loosen clothes.

Remove unnecessary clothing and make sure clothing is light and loose.

If you do not begin to feel better within an hour of applying these treatment measures, consult a doctor immediately.

To cool the body to a normal temperature, your doctor may use these heatstroke treatment techniques:

Immerse yourself in cold water.

It has been shown that the most effective way to reduce core body temperature quickly is to take a bath in cold or ice water. The sooner they can immerse you in cold water, the less chance there is of death or organ damage.

Use evaporative cooling techniques.

If your core body temperature is not within the limits of heat stroke and cold water immersion is not possible, healthcare workers may try to lower your body temperature using a method of evaporation. Cold water is vaporized while hot air is blown over the body, causing the water to evaporate and cooling the skin.

Wrap yourself in ice and cooling blankets.

Another method is to wrap yourself in a special cooling blanket and apply ice packs to the groin, neck, back and armpits to bring down the temperature.

Give yourself medicine to stop the chills.

If treatments to lower body temperature give you chills, your doctor may give you a muscle relaxer, such as a benzodiazepine. Chills raise body temperature and make treatment less effective.