Heat Cramps

Reviewed on 6/17/2022

Things to Know About Heat Cramps

A person holding their calf due to heat cramps.
Muscle spasms are the only sign of heat cramps, and the symptoms of heat cramps are painful, involuntary, and brief.
  • Heat cramps are painful, brief muscle cramps that occur during or after exercise or work in a hot environment. Muscles may spasm or jerk involuntarily. Cramping may also be delayed and occur a few hours later.
  • Heat cramps are thought to be caused by a deficiency in electrolytes.
  • Heat cramps signs and symptoms are painful muscle spasms usually involving the legs, chest, or abdomen.
  • Risk factors for heat cramps include:
    • Age (Infants, children, and elderly)
    • Alcoholism
    • Working or living in a hot environment
    • Certain medications
    • Drug abuse
  • Heat cramps are treated by rehydrating with fluids by mouth or intravenously (IV).
  • Heat cramps can be prevented by avoiding strenuous work or exercise in a hot environment and staying hydrated.

What Are Heat Cramps Symptoms and Signs?

Muscle spasms are the only sign of heat cramps. The symptoms of heat cramps are cramps that are:

  • Painful
  • Involuntary
  • Brief
  • Intermittent (they come and go)
  • Usually self-limited (they resolve on their own)

What Causes Heat Cramps?

The exact cause of heat cramps is unknown, but it is most likely related to electrolyte deficiencies. Various essential minerals, such as sodium, potassium, calcium, and magnesium, are known as electrolytes. They are important for many body functions, and an electrolyte imbalance can cause medical problems.

Sweat contains a large amount of sodium, and drinking fluids with inadequate sodium content after sweating profusely may result in a serious low-sodium condition called hyponatremia.

Those at most the risks for heat cramps are:

  • Infants and young children
  • The elderly
  • Individuals who live by themselves or who cannot afford air conditioning in hot environments
  • Those who consume alcohol
  • Individuals who work or exercise in a hot environment
  • Those taking certain prescription medications. Some medications can impair the body's sweat and heat regulation (for example, psychiatric drugs, tranquilizers, OTC cold medications, and antihistamines).
  • People who abuse the drug Ecstasy or other synthetic drugs of abuse.

Are Heat Cramps Related to Heat Exhaustion and Heat Stroke?

Heat cramps may be the first sign of a more serious heat-related illness such as heat exhaustion or heat stroke. Heat exhaustion and heat stroke are more severe forms of heat-related illnesses. While these are not the same medical problems, there are some overlapping symptoms of each disease as the patient's condition worsens.

Signs and symptoms of heat exhaustion (heat stroke) are as follows:

  • Sweating
  • Weakness
  • Fast pulse
  • Feeling faint
  • Muscle cramping
  • Nausea and/or vomiting
  • Signs and symptoms of heat stroke are:
  • Hot, red, dry skin
  • Altered level of consciousness (not acting right)
  • Passing out
  • Extremely high body temperature

What Is the First Aid Home Treatment for Heat Cramps?

Heat cramps usually resolve on their own and don't require any specific home medical treatment. Home remedies to help the heat cramps resolve more quickly include:

  • Rest in a cool place and drink replacement fluids such as electrolyte beverages or sports drinks (for example, Gatorade or Powerade).
  • Stop the activity being performed
  • Go to a cooler environment
  • Gently stretch the muscles that are cramping

Salt tablets by themselves should not be used. They can cause stomach upset and don't adequately replace fluid volume lost.

What Is the Medical Treatment for Heat Cramps?

A doctor will evaluate the affected individual and may diagnose them with severe heat-related illness symptoms and signs, and possibly provide them with IV fluid rehydration. However, oral rehydration and electrolyte replacement are usually sufficient to treat heat cramps.

When Should You Call a Doctor for Heat Cramps?

Heat cramps can be very painful. A person suffering from heat cramps should seek medical attention if the symptoms do not go away with rest, cooling off, and after restoring fluid and electrolytes.

Heat cramps may be the early signs of heat exhaustion or heat stroke, which are more severe forms of heat-related illnesses.

Seek medical care immediately or call 911 if these conditions develop:

  • The person is unable to drink sufficient fluids because they have nausea or are vomiting. The affected individual may need IV rehydration with normal saline.
  • The person has more severe symptoms of heat-related illness, including:

If a person has more severe forms of heat-related illness or thinks they require IV fluids to rehydrate, seek medical care at an emergency department.

What Is the Prognosis for Heat Cramps?

Heat-induced muscle spasms usually resolve without any medical treatment.

Can You Prevent Heat Cramps?

A person should remove themselves from a hot and humid environment, or hydrate well prior to and during activities in such an environment.

If a person works or exercises in a hot environment, they may experience heat cramps during the first few days of work or exercise. Once accustomed to the environment, and with adequate electrolyte replacement, the affected individual should have no further problems.

Heat Stroke Symptoms and Signs

Heat stroke usually follows two other heat-related problems, heat cramps and heat exhaustion. Signs and symptoms of these two conditions are muscle cramps followed by exhaustion and profuse sweating. As these conditions progress the person may have

  • a rapid pulse,
  • rapid breathing,
  • dizziness, and
  • headache.

These signs and symptoms may linger and progress to heat stroke. Heat stroke occurs when the body temperature reaches 104 F or 40 C or 105 F and 40.5 C in children, and the body stops sweating.

Reviewed on 6/17/2022
"Warning Signs and Symptoms of Heat-Related Illness." CDC. Updated: Nov, 03, 2017.