Heat Cramps


Heat cramps facts

  • Heat seizures are intermittent and involuntary spasms of large muscles that occur in an individual who is physically active in hot weather.
  • Spasms of heat, heat exhaustion and heat stroke are collectively known as heat-related diseases. Heat cramps are the least severe of the three, but they can still be very painful and disturbing.
  • Heat cramps usually affect the major muscles that are stressed in a hot environment.
  • People at risk for heat cramps include those who work, exercise or are active in a hot environment.
  •  People with impaired temperature control mechanisms, such as infants, young children and the elderly, are also at increased risk of heat.
  •  Heat seizures are the oldest symptoms of heat-related illness.
  •   Symptoms of heat cramps include excessive sweating with involuntary cramping of large muscles in the body.
  •   Heat cramps can also be a symptom of heat exhaustion.
  • The diagnosis of heat spasms is usually made by reviewing the patient’s history and identifying the involuntary muscle groups in the spasm.
  •   The treatment of heat cramps includes rest, body cooling, hydration, stretching of muscles that contract.
  •   Heat cramps can be prevented by avoiding exercise or work during the daytime heat, drinking plenty of fluids and resting in cold or shaded areas when possible.

What are heat cramps?

Heat seizures are involuntary intermittent muscle spasms that occur in a physically active person (for example, working or exercising) in hot or humid weather. They are often associated with drought. Heat cramps usually affect the major muscles that are stressed in the hot environment. In most cases, it involves thighs and legs (thigh muscles, hamstrings, leg), basic muscles (abdominal wall and back) and arm muscles (biceps, triceps).

Heat contractions can also occur after the activity is completed. For example, construction workers or bishops can cause seizures a few hours after the end of their work.

Who is at risk of getting heat?


While heat contractions tend to affect people working in a hot environment, it should be noted that heat contractions are one of the symptoms associated with thermal overheating as part of the spectrum of heat-related diseases. These people who suffer from poor temperature control mechanisms are more likely to develop heat-related illnesses. The most effective way to cool the body is through sweat, and then sweat evaporates into the environment.

The most susceptible to heat contractions include:


  •  Babies and young children, as they depend on others to avoid heat, dress them appropriately (avoid infant stenosis because it prevents the movement of air in the skin to promote the evaporation of sweat) and provide enough fluids to drink.
  •   Older people because they can suffer from basic medical conditions, such as heart and lung diseases, and can easily become dehydrated.
  • People who live alone or who can not afford air conditioning are at a higher risk of contracting the disease associated with heat.
  •   A variety of medications can weaken the body’s sweat and regulate heat. Examples of medications include psychotropic medications, including antipsychotics and sedatives. Cold medicines and over-the-counter antihistamines also weaken the body temperature control mechanism.
  • Consumption of alcohol.


What causes heat cramps?


While it was thought that dehydration and electrolyte imbalance were the cause of muscle spasms, there are alternative theories as to why muscle contractions occur when the body is exposed to heat.

Since heat cramps begin after a large exercise in a warm environment where the affected individual begins to sweat profusely, the theory was that depleted muscles of water and sodium affect their ability to contract and relax. Some recent research suggests that the muscles of excess activity and work, and the ability of the muscle to regulate its contraction are lost and this is called a change of neuronal and muscular control. Regardless of the cause, the diagnosis and treatment of heat spasms remain the same.


What are the signs and symptoms of heat cramps?


Spasms of heat are the closest symptom of a spectrum of heat-related illnesses.

  • There is usually great sweating with involuntary spasms of large muscles in the body.
  •  Muscle cramps are usually those that have been stressed.
  •  Athletes and soccer players tend to have leg cramps, but people who lift objects as part of their work may suffer cramps in the arms or in the basic muscles of the trunk, such as the abdominal muscles.
  •   Heat contractions usually begin after a major activity, but may also occur hours after the activity is completed.Do people who suffer from heat cramps tend only to muscle cramps? If the individual has signs or other symptoms such as dizziness, weakness, nausea, vomiting and headaches that may suffer from heat exhaustion. Affected people who have stopped sweating or who develop a fever and become confused can cause heat stroke, a true emergency medical condition.


When should an individual seek medical attention for heat contractions?


Heat cramps can usually be treated when and where they occur. The affected individual must stop all activities and find a cool place to rest. Muscle spasms and seizures can be overcome by gently stretching the tense muscles. People can often replace the loss of fluids by drinking a combination of water, sports drinks or other electrolyte replacement solutions.

If the contractions can not be controlled, the injured person should get medical attention. There is no specific condition that distinguishes heat spasms from heat exhaustion. The symptoms of these conditions form a spectrum of mild to moderate heat-related illnesses and the symptoms may interfere. Severe heat cramps can actually be heat exhaustion. This is especially true if a person has nausea or vomiting and can not replace the loss of fluids, if they have great fatigue and weakness, or have excessive sweating that does not stop when placed in a cooler environment.

Heat stroke is a real emergency medical condition and can be fatal. The body’s own cooling capacity no longer works and, as the temperature increases, sometimes more than 106 F (41 C), confusion and coma may occur. Emergency medical services (911 call) should be activated immediately if the individual is thought to have sunstroke. Waiting for assistance access, the person should be moved to a cool place, clothes should be removed to help circulate the air over the body, should be sprayed with cold water or a sponge on the body to try to cool it.

Prevention is the key to preventing seizures from heat or other heat-related illness. The person who has had heat cramps is more likely to develop them again. Some occupations have a higher risk of heat contractions, for example, construction workers and exposed roofs are not only exposed to the heat of the sun, but also due to the radiant heat of hot tiles and surface coatings. It may be useful to adapt to the warm environment for a period of days to allow the body and muscles to adapt to the needs of water and electrolytes.


How are heat cramps diagnosed?

Heat spasms are usually diagnosed after taking the patient’s history. It is important to know the environment where the person affected by cramps works because of the heat, exercise, etc.

  •  How hot was it?
  • How wet?
  •  Was there enough air circulation?
  •  What activity is carried out and for how long?
  •   When did the seizures start? In what muscles did you participate?
  •   Was there sweating associated with that?
  •   Has the affected individual been affected by the hot environment?
  •  Was the person drinking enough water? It can be a sign of heat or color spasms related to heat-related illness. When the body becomes dehydrated, the kidneys maintain the water and produce a strong, concentrated odor, darker, yellow urine. If there is enough water in the body the urine tends to be clear.The physical examination is often relatively normal. Narrow muscles can be painful to the touch and if there is no adequate fluid replacement, the muscles can contract again when they are taken through the normal range of motion. The physical examination may find signs of dryness, such as dry mouth and tongue, lack of sweat in the armpit and thigh, and low intake of urine. Vital signs may be an idea (eg, low blood pressure) and rapid heart rate (arrhythmias). A person’s blood pressure can be much lower compared to lying (hypotension).


What are the complications of heat cramps?

There are few long-term consequences of heat cramps, however, once a person experiences heat cramps, they may be at risk for future episodes.

How can heat cramps be prevented?

Prevention is the best treatment for heat cramps. If possible, try to avoid working or exercising in the heat of the day, but if it is required, acclimating to the hot weather is important. Drink plenty of fluids and if the activity lasts a prolonged period of time, consider using sports or balanced electrolyte drinks. This is especially true if significant sweating occurs and electrolytes are lost through sweat. Try to rest in cool or shaded areas whenever possible.


What is the prognosis for heat cramps?

Heat cramps resolve with relatively simple treatments including rest, hydration and stretching. It is important to remember that heat cramps are the initial presentation of heat related illness and may progress to the more serious conditions of heat exhaustion or heat stroke.

Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine


Kravchenko J, etal. Minimization of Heatwave Mortality and Morbidity.American Journal of Preventive Medicine 2013: 44(3) 274-82

Schwellnus MP. Cause of Exercise Associated Muscle Cramps (EAMC) – altered neuromuscular control, dehydration or electrolyte depletion. Br J Sports Med 2009;43:401-408

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