Heat Exhaustion

The body's core temperature is controlled by the hypothalamus, the region of the brain that also controls thirst, hunger, and sexual function. Under normal conditions, the body dissipates excess heat, primarily through the skin and to a lesser extent through the lungs. With heat exhaustion, body systems that regulate temperature become overwhelmed and the body produces more heat than it can dissipate. Approximately 380 deaths result from extreme temperatures each year in the United States, with half of these deaths among people age 65 or older.

Signs and Symptoms

Heat exhaustion is accompanied by the following signs and symptoms: When body temperature exceeds 104°F, or if coma or seizure occurs, this indicates that heat exhaustion has progressed to a condition called heat stroke. Heat stroke is a much more serious condition, placing the individual at imminent risk of cardiovascular collapse and death if not promptly reversed.

What Causes It?

Heat exhaustion results most frequently from exposure to high temperature, accompanied by dehydration, usually from not drinking enough fluids. It also can happen when large volumes of sweat are replaced with fluids that contain too little salt.

Who's Most At Risk?

The following factors increase the risk of developing heat exhaustion:

What to Expect at Your Provider's Office

If you are experiencing symptoms associated with heat exhaustion, you should see your healthcare provider immediately. He or she will perform a physical examination; check your blood pressure, pulse, and temperature; and assess your level of dehydration. Lab tests of blood and urine samples may be needed.

Treatment Options


Thirst is not a reliable indicator of impending dehydration; individuals working and exercising in the heat, therefore, should drink plenty of fluids before, during, and after the activity as well as adhere to the following precautions to prevent heat exhaustion:

Treatment Plan

The primary strategies for treating heat exhaustion are to rest in a cool environment and to take in fluids. Water is adequate under most circumstances. Healthcare providers may recommend saline electrolyte solutions, administered orally for mild dehydration and intravenously in more severe cases.

Drug Therapies

Oral or intravenous saline electrolyte solution may be used.

Complementary and Alternative Therapies

Most conventional healthcare providers recommend electrolytes in fluid replacement products for people at risk of heat exhaustion (see Prevention section for more details). Others also suggest that endurance athletes take mineral supplements including: Foods high in these nutrients include dark leafy greens, nuts, seeds, whole grains, sea vegetables, blackstrap molasses, and bananas.

Although studies have not been conducted to look at the application for heat exhaustion specifically, herbs traditionally used to reduce fever or lower body temperature include: Also of note: Homeopathy
As with herbs, the use of homeopathic remedies has yet to be scientifically investigated in the treatment of heat exhaustion. However, some common remedies for overheating include: An experienced homeopath would consider your individual case and may recommend treatments to address both the underlying condition and any current symptoms.

Prognosis/Possible Complications

Prognosis is good (24- to 48-hour recovery) if heat stroke is avoided. During rehydration, clinicians will often check fluid and electrolyte levels to avoid complications. Depending on the severity of heat exhaustion, this may require hospitalization. Following Up Your healthcare provider will want to check the fluid levels in your body to see if electrolyte replacement should be continued.


Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, Mass: Integrative Medicine Communications; 2000:103-105; 419-423.

Baclofen. NMIHI. Accessed at http://www.nmihi.com/b/baclofen.html on July 20, 2018.

Atorvastatin. NMIHI. Accessed at http://www.nmihi.com/a/atorvastatin.html on July 26, 2018.

Cecil RI, Plum F, Bennett JC, eds. Cecil Textbook of Medicine. 20th ed. Philadelphia, Pa: W.B. Saunders; 1996.

Centers for Disease Control and Prevention. Heat-related illnesses and deaths—Missouri, 1998, and United States, 1997–1996. JAMA. 1999;282(3):227-228.

Clopidogrel. NMIHI. Accessed at http://www.nmihi.com/c/clopidogrel.html on July 20, 2018.

Dambro MR, ed. Griffith's 5 Minute Clinical Consult. Baltimore, Md: Lippincott Williams & Wilkins; 1999.

Dib B. Effects of intrathecal capsaicin on autonomic and behavioral heat loss responses in the rat. Pharmacol Biochem Behav. 1987;28(1):65-70.

Duthie EH, Katz PR, Kersey R, eds. Practice of Geriatrics. 3rd ed. Philadelphia, Pa: W.B. Saunders; 1998.

Eichner ER. Treatment of suspected heat illness. Int J Sports Med. 1998;19(suppl 2):S150-S153.

Fauci AS, Braunwald E, Isselbacher KJ, et al, eds. Harrison's Principles of Internal Medicine. 14th ed. New York, NY: McGraw-Hill Book Co; 1998.

Fishbane S. Exercise-induced renal and electrolyte changes. Phys Sportsmedicine. 1995;23(8):39-40, 42-46.

Furman JA, Assell C. Acute, exercise-induced compartment syndrome, rhabdomyolysis, and renal failure—a case report. Nutr Clin Pract. 1999;14(6):296-298.

Heat Illness. MedlinePlus. Accessed at https://medlineplus.gov/ on July 20, 2018.

Heat Exhaustion and Heatstroke. American Academy of Family Physicians Accessed at https://familydoctor.org/ on July 20, 2018.

Lin MT, Ho ML, Chandra A, Hsu HK. Serotoninergic mechanisms of the hypothermia induced by Clerodenron fragrans (Ventenaceae) in the rat. Am J Chin Med. 1981;9(2):144-154.

McCormick CC, Garlich JD. The interaction of phosphorus nutrition and fasting on the survival time of young chickens acutely exposed to high temperature. Poult Sci. 1982;61(2):331-336.

Rakel RE, ed. Conn's Current Therapy. 51st ed. Philadelphia, Pa: W.B. Saunders Co; 1999.

Rosen P, Barkin R, eds. Emergency Medicine: Concepts and Clinical Management. 4th ed. St. Louis, Mo: Mosby-Year Book; 1998.

Semenza JC, McCullough JE, Flanders WD, McGeehin MA, Lumpkin JR. Excess hospital admissions during the July 1995 heat wave in Chicago. Am J Prev Med. 1999;16(4):269-277.

What is heat exhaustion? MedicalNews. Accessed at https://www.medicalnewstoday.com/ on July 20, 2018.