Heat exhaustion

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at June 26, 2016
StartDiseasesHeat exhaustion

Heat exhaustion is a condition that occurs when the process of thermoregulation fails. It commonly occurs as a result of exposure to excessive heat without proper hydration. It is a condition that is mostly preventable and easily treatable but could be life-threatening if left untreated. 


Definition & Facts

This heat-related condition involves hyperthermia and is usually referred to as the second most severe of three heat-related illnesses. The first and least severe is heat cramps which usually involve heavy sweating and some cramping. The most dangerous heat-related syndrome is heat stroke which could involve fainting, threatens vital organs, and could be fatal.

Heat exhaustion is the result of the body overheating. The body is capable of handling temperature increases, but it has limits. A body is able to handle a temperature rise by increasing the flow of blood to the skin, which helps it expel sweat to control the temperature by cooling the epidermis.

The body's cooling system makes the heart work harder and drains some bodily fluids. The intensity of this process is increased, however, with heat exhaustion. This condition overworks the heart, and the individual becomes dehydrated. It is important to note that other factors can increase the risk of a heat-related syndrome, like being overweight or having a heart condition.

Around 31 percent of deaths associated with heat exhaustion are due to natural heat. Experts have also noted that treating the issue as soon as symptoms are detected makes heat exhaustion 100 percent curable.

Symptoms & Complaints

The following are some of the symptoms associated with heat exhaustion:


Heat exhaustion is the result of several factors such as the body's failure to maintain a normal body temperature: 98.6 degrees Fahrenheit (37 degrees Celsius). Sweat is what the body uses to cool down due to evaporation, but sometimes this mechanism does not function properly. One of the issues that could hinder sweat's ability to evaporate is a humid environment. The moisture in the air makes it harder for sweat to evaporate.

There is also the possibility that the patient is participating in a strenuous activity, such as exercise or work. This activity could be raising the temperature inside the body, which is exacerbated by the heat in the environment.

Another factor could be wearing multiple layers of clothing during periods of extreme heat. Not drinking enough water could also make a heat exhaustion episode more probable as could alcohol use. Alcohol disrupts the body's process of regulating its core temperature. Those who are elderly, people with mental disorders, young children, and people who already have a fever are at greater risk of experiencing heat exhaustion.

Diagnosis & Tests

A medical professional will go through a checklist to ensure that the symptoms correlate to a heat exhaustion episode. A blood test will also be administered; a heat exhaustion episode might end up leading to heat stroke if the blood is low in sodium or potassium, which the blood test will investigate.

The blood test may also include an arterial blood gas test which will measure the gases in the bloodstream. Clinical urine tests will be administered as well to ensure that the kidneys are functioning correctly. This is done because kidney failure is associated with heat stroke. Muscles and internal organs will also be checked to ensure no damage has been incurred due to a heatstroke.

Treatment & Therapy

There are several treatments that could be employed to prevent the heat exhaustion episode from worsening or to force the episode to abate. One of the easiest treatments is to find a cool place to rest. This could be an air-conditioned location or a shady location somewhere under a tree or the porch of a home. Sitting in front of a fan could also be helpful in this situation. A person can use a spray bottle to spritz cool water over the skin, or use a cool wet towel to cool the body down. Loosening the clothes could also help alleviate the heat exhaustion victim.

These activities should help the body restore a healthy temperature, but there is a possibility that they will not work. If a person afflicted with heat exhaustion does not feel better within one hour, the person may need medical attention. Medical attention will consist of intravenous fluids to rapidly rehydrate the body, along with the use of cooling blankets. Temperature will also be closely monitored during medical treatments. It is important to seek medical treatment because complications that could result include brain damage and damage to other vital organs.

Prevention & Prophylaxis

Prevention is the best solution to this potentially dangerous heat syndrome. The United States Department of Labor recommends 'water, rest, and shade' as preventive tools for people who work outside in the heat.

Prevention requires the consumption of adequate amounts of water. Drinking water every fifteen minutes may help ward off heat exhaustion if a person is working outside. Some experts suggest drinking sports drinks that contain electrolytes.

Loose clothes are recommended because they allow the body to breathe and sweat properly. Dark-colored clothing retains more heat, so light-colored clothing is preferable. It is wise to avoid strenuous activities on days when the heat is excessive or to take frequent breaks in the shade if engaging in work or recreation outside. It is also advisable to wear sunscreen that has a high enough sun protection factor (SPF) when outside.

Training the body to handle heat can help. To train the body, one must work in hot temperatures while allowing the body to freely sweat, and drinking enough liquids during these training exercises will keep the body hydrated. Training must also include breaks from time to time to give the body a chance to recuperate.