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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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In this Article

• Heat exhaustion facts
• What is heat exhaustion?
• What causes heat exhaustion?
• Who is at risk for heat exhaustion?
• What are the symptoms of heat exhaustion?
• When should a person seek medical care for heat exhaustion?
• How is heat exhaustion diagnosed?
• How is heat exhaustion treated?
• What are the complications of heat exhaustion?
• How can heat exhaustion be prevented?
• What is the prognosis for heat exhaustion?
• Patient Comments: Heat Exhaustion - Symptoms
• Patient Comments: Heat Exhaustion - Treatments
• Find a local Doctor in your town
• Heat Exhaustion Index

Heat exhaustion usually affects people who are working or exercising in a hot environment. Those at risk for heat exhaustion include:

• Infants and young children are at risk because their temperature regulation mechanisms are not fully developed. They also are dependent upon others for water and appropriate clothing.
• The elderly are similarly at risk because of underlying medical conditions that limit the ability to sweat including poor circulation, skin changes, and chronic medication usage.
• Socioeconomic issues increase the risk of heat exhaustion if access to air conditioning is limited. During heat waves, large cities often open cooling centers to help minimize the risk of large numbers of people succumbing to heat-related illness.
• Certain medications such as antidepressants, antipsychotics, and tranquilizers may impair the ability of the body to sweat.
• Alcohol consumption
• The overweight or obese

The body has the ability to acclimate to hot weather but if heat waves come suddenly, or if a person travels from a cooler environment to a hot environment, the risk of heat exhaustion increases. It takes about 7 to 10 days for the body to adapt to hot weather. A non-acclimate person can produce a liter or almost a quart of sweat in an hour that assists in cooling the body. A person who is acclimated to the heat can produce 2 or 3 liters of sweat per hour, doubling or tripling the cooling potential for the body.

Individuals with heat exhaustion tend to have symptoms such as:

• Profuse sweating
• Weakness
• Muscle cramps
• Headache
• Nausea and vomiting.

As dehydration increases from the loss of body water, lightheadedness may occur and fainting (syncope) may occur especially, if the affected individual stands up quickly (due to orthostatic hypotension). A low grade fever also may be present.