Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Heat Cramps

By

David Tanen

, MD, David Geffen School of Medicine at UCLA

Last full review/revision Feb 2021| Content last modified Feb 2021
CLICK HERE FOR THE PROFESSONAL VERSION

Heat cramps are severe muscle spasms resulting from a combination of prolonged exercise, heavy sweating, and excessive water replacement in extreme heat.

During sweating, salts (electrolytes Electrolyte Balance read more ) and fluids are lost, but drinking large quantities of water dilutes the salts, causing cramps. Heavy sweating is most likely to occur on warm days, especially during or after strenuous exertion. Heat cramps are common among all of the following:

  • Manual laborers, such as engine-room personnel, steelworkers, roofers, and miners

  • Athletes, especially mountain climbers or skiers, whose many layers of clothing may keep them from noticing their heavy sweating, and tennis players and runners who do not take time to replace salts lost in sweat

  • Military trainees

Heat cramps are strong contractions in muscles of the hands, calves, feet, thighs, or arms. The contractions cause muscles to become hard, tense, and painful. The pain can be mild to intense. Fever does not typically occur.

Mild heat cramps can be treated by having the person rest in a cool environment and drink beverages that contain salt or eat salty food. Drinking 1 to 2 quarts (about 1 to 2 liters) of a sports drink or water containing 2 teaspoons of salt is usually enough. Severe heat cramps are treated with fluids and salts given by vein (intravenously). Stretching the involved muscle often gives immediate relief of pain.

NOTE: This is the Consumer Version. DOCTORS: CLICK HERE FOR THE PROFESSONAL VERSION
CLICK HERE FOR THE PROFESSONAL VERSION
Others also read
Test your knowledge
Fractures of the Jaw and Midface
Fractures to one or more facial structures can result from a single injury. Jaw fractures may occur to the mandible, or lower jaw, or to the maxilla, bone of the upper jaw. Other structures susceptible to fracture include the eye sockets, nose, and cheek bones. Which of the following facial structures is most likely to fracture if a person falls from a great height or hits the windshield of a car face-first during a motor vehicle accident?
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
TOP