Heat Cramps, First Aid

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Heat cramps are a form of heat illness. Heat illness occurs when a person's core body temperature rises above a safe level of the body's internal temperature range. Heat cramps are the earliest sign of heat illness. Loss of salt in the body due to excessive perspiring causes the painful, involuntary muscle spasms. If the person does not take precautions to cool off and rehydrate at this point, more severe stages of heat illness will occur in a rapid progression, resulting in a potentially life-threatening situation.

See the Heat Exhaustion or Heatstroke topics via the Disease List if later stages of heat illness are suspected.

First Aid Guide
Use a combination of the following measures, depending on the circumstances and means available:

  • Have the person rest in a shaded area or cool or air-conditioned building, room, or car.
  • Give the person an electrolyte beverage, such as Gatorade® or Pedialyte®, or water if not available. Note: You can make a salted drink by adding 1 teaspoon of salt to one quart of water.
  • Pour water over the person or spray with a hose. Note: Do not do this if the person is disoriented.
  • Wrap the person in wet cloth, and position a fan toward him/her. Evaporation of water on the skin aids in cooling.
  • Apply cold compresses (eg, to neck, armpits, groin).
  • Attempt to relax the cramped muscles by massaging them gently but firmly.

If possible, take the person's temperature while starting cooling measures and continue to check his/her temperature every few minutes. Once it has gone down to 100° F, you can discontinue cooling measures but continue to check the person's temperature every 30 minutes for 34 hours.

Who's at risk?

People most susceptible to heat cramps are those who are outdoors on a hot, humid day or those inside in a poorly ventilated area, particularly children, the elderly, or the obese. Children and the elderly show the fastest progression of symptoms and can collapse suddenly.

Those on certain medications can suffer from heat illness, as well, as medications can alter the way the body handles heat and sun. Those who drink alcohol before, during, or after vigorous activity are more susceptible to heat illness, as are people who do heavy work with inadequate fluid intake.

Signs and Symptoms

Heat cramps often present as muscle cramps (eg, in the legs, arms, abdomen, or back), heavy perspiration, and weakness/lightheadedness. The cramps are often more painful and last longer than the type of leg cramps that occur during the night.

You can differentiate the least-severe form of heat illness, heat cramps, from more-severe forms by comparing the person's symptoms described above to the following:

  • Heat exhaustion – Feelings of nausea, light-headedness, or thirst, and the person may act irrationally, have dilated pupils (pupils are larger than normal), be very sweaty, or have cool and moist skin that is either reddened or pale.
  • Heatstroke includes some or all of the following symptoms:
    • A high body temperature (above 102° F)
    • Skin that is red and hot with lack of sweating (sweating that has stopped)
    • Small pupils
    • A rapid, weak pulse
    • Rapid, shallow breathing
    • Extreme confusion or irritability
    • Weakness
    • Seizures
    • Unconsciousness

When to Seek Medical Care

If you suspect heatstroke, if the person does not improve with the above self-care measures after an hour, or if the symptoms worsen, seek emergency medical care.

Treatments Your Physician May Prescribe

Your physician may want to use conservative measures and give suggestions for how to recover from possible dehydration or address any other illness that may have caused the heat cramps.

Trusted Links

MedlinePlus: Heat Illness
MedlinePlus: Muscle Cramps