Heat Cramps

Heat cramps, while likely not caused by heat alone, are a subcategory of Exercise-Associated Muscle Cramps (EAMC). The exact mechanism of muscle cramps in warm environmental conditions is unknown but they can be caused by dehydration or lack of adequate electrolytes in the diet. Although muscle cramping is not a cause of sudden death, it can be confused with a more serious condition, exertional sickling (cramps with no palpable muscle contraction).

Heat cramps are painful involuntary cramping often in the legs, arms, or abdomen with muscle contraction that can easily felt. Heat cramps usually occur in the preseason conditioning phase when the body is not properly conditioned and more subject to fatigue. Heat cramps can easily be treated with rest, stretching the muscle, and rehydration of fluid and electrolytes.

How do you prevent cramps?

It may be impossible to completely prevent a cramp from occurring, however, certain factors can be modified in order to reduce the incidence of future heat cramps.

The most effective ways to prevent cramping in athletes include:

  • Acclimatizing the athlete to warm/hot environments if their sports require exercise in hot environmental conditions can help prevent heat cramps.  Heat acclimatization protocols can be found here.
  • Similar to heat acclimation, acclimating to exercise by gradually progressing intensity and duration before requiring the athlete to perform all out in an event or extensive workout session healp prevent heat cramps.  This process may also help prevent athletic injuries!
  • Educating athletes to replace fluids and salt lost in their sweat.  This can be done by calculating whole body sweat loss during exercise using this sweat loss equation.  Each athlete slightly differs in the amount of sweat and salt losses during exercise.  Also keep in mind that these factors change depending on the temperature and humidy of the ambient environments, so sweat testing should be specific to the conditions in which the athletes are exercising.
  • Maintain a balanced electrolyte level by consuming electrolyte rich drinks before and during the athletic event or practice session if physical activity lasts longer than one hour in duration.  Certain individuals naturally expel more sodium in their sweat compared to the average individual.  These people may need supplemental/extra sodium in their diet.
  • Removing excess clothing during physical activity may help reduce the chance of getting heat cramps by allowing for greater evaporation, keeping core body temperature lower during exercise.  For example, if a field hockey goalie is performing conditioning drills during which protective equipment is unneccessary, the athlete should remove the equipment during this portion of the conditioning session.


What puts an individual at risk for cramps?

  • Exercise in heat when the individual is not accustomed to exercising in the hot conditions
  • Profuse sweating or body water loss during exercise.  These athletes lose a considerable amount of electrolytes through their sweat which predisposes them to heat cramping
  • Exercising for an extended duration of time or participating in multiple practice sessions per day without replenishing the salts and water lost during sweating
  • Muscular fatigue
  • Wearing additional layers of clothing, protective gear, or equipment


Look for these symptoms in athletes when cramps are suspected:

  • Dehydration, thirst, sweating, transient (short term) muscle cramps, and fatigue
  • Painful, involuntary muscle spasms (usually occurring in the legs) associated with exercise in the heat when athletes have been sweating profusely
  • A precursor to the initial onset of cramps involves muscle twitches or fasciculations.  If this occurs, remove the athlete from the heat and encourage rehydration with an electrolyte beverage


How do you know if these are cramps?

Heat cramping is often confused with exertional sickling but may be differentiated by the following ways.

Symptom/Factor EAMC Exertional Sickling
Pain Factor More excruciating pain; can be pinpointed to a location Pain is strong, however, is more generalized over body
State of Muscles Muscles “lock-up”; Visibly contracted and rock hard Muscles are weak; athletes slump, push through instances of collapse
Physical Symptoms Athletes may writhe or yell in pain Sickling athletes lie fairly still without yelling
Prodrome of Muscle Twinges Yes None
Occurrence during Workout/Session Occurs during or after intense workouts (after 30 minutes) Generally occurs within first half hour during intense workouts
Body Temperature Athlete’s core temperature is elevated Athlete’s core temperature is not greatly elevated

How do you treat the individual?

  1. Remove the athlete from the exercise session, workout, or practice and have them rest in the shade or an air-conditioned room.
  2. Stretch, massage and knead the muscle that are cramping in its full-length position (joints should be extended).
  3. Provide the athlete with cold fluids, such as water or an electrolyte sports drink to replace sweat losses.
  4. Provide food high in salt content to replenish the electrolytes lost from sweat.  If this is not available consider providing a solution of 1/2 teaspoon salt dissolved in 16-20 ounces of water prior to or post cramping.
  5. In cases of heat cramps that persist, use ice massage on the affected muscle.


When can the individual return to activity?

Once an athlete has rested and replenished the fluids and electrolytes lost from their sweat, they can usually return to play during that same exercise session or practice.  Determining the athlete’s sweat rate could be beneficial for their knowledge in understanding their body’s requirement of fluid during exercise and how to appropriately replenish water stores after exercise.



  1. Armstrong LE. Exertional Heat Illnesses. Human Kinetics; 2003.
  2. Armstrong LE, Casa DJ, Millard-Stafford M, Moran DS, Pyne SW, Roberts WO. American College of Sports Medicine position stand: exertional heat illness during training and competition. Med Sci Sports Exerc. 2007;39:556–572.
  3. Binkley HM, Beckett J, Casa DJ, Kleiner DM, Plummer PE. National Athletic Trainers’ Association position statement: exertional heat illnesses. J Athl Train. 2002;37:329–343.