Muscle Cramps

muscle cramp
Muscle Cramp. Jeannot Olivet/Getty Images

Muscle cramps (also called muscle spasms or charley horses) are are sudden, usually painful, contractions of a muscle or group of muscles. The cramping muscle becomes tight and hard, and very painful. Typically a muscle cramp is painful enough to get you to stop doing whatever it is you were doing when it began.

Cramps can happen with any muscle, but most typically occur in the calf and foot muscles.

Other muscles commonly prone to cramping include the thigh, hamstrings, arms, hands, and rib and abdominal muscles. Almost everyone, sooner or later, will experience muscle cramping.

Particularly common in people over 50 years of age is nocturnal leg cramping - muscle cramps that occur while in bed (either awake or asleep), usually affecting the calf or foot muscles.

What Causes Muscle Cramps?

  • Idiopathic - The large majority of muscle cramps cannot be attributed to any identifiable cause. When doctors don’t know the cause of a medical phenomenon, they say it is “idiopathic,” which sounds more sophisticated than saying, “I don’t know.”
  • Biomechanical - leg cramps can be associated with flat feet or other structural abnormalities of the legs and feet. Cramps are also more common in people who spend too much time sitting, or standing on concrete flooring.
  • Neurological - Several neurological conditions can increase muscle cramping, especially Parkinson’s disease.
  • Dehydration - Dehydration from diuretics or excessive sweating may lead to muscle cramps.
  • Electrolyte disorders - low blood levels of potassium, calcium or magnesium are associated with muscle cramping
  • Pregnancy - muscle cramps are more common during pregnancy, possibly due to magnesium depletion
  • Metabolic disorders - diabetes, hypoglycemia, alcoholism, and thyroid disease are associated with muscle cramping

Despite this long list of potential causes, in the large majority of cases muscle cramps have no particular cause - they are idiopathic.

How To Treat Muscle Cramps

When you experience an acute muscle cramp, you can generally relieve it rapidly by stretching and massaging the affected muscle. Icing the muscle or an Epsom salt bath might also be helpful. If the cramp occurred during exercise, it’s time to take a rest and get rehydrated.

If you have nocturnal leg cramps, regularly stretching your calf muscles may help prevent the episodes, as well as getting regular exercise. Wearing properly fitted shoes can also help. And loosening the bed covers at the foot of the bed (not tucking them in) can help prevent cramping.

If cramping is frequent or severe, or if nocturnal leg cramps are preventing sleep, you should consult with your doctor. Also, if you experience leg cramps regularly while walking or climbing stairs, you may have peripheral artery disease. See your doctor.


Parisi L, Pierelli F, Amabile G, et al. Muscular cramps: proposals for a new classification. Acta Neurol Scand 2003; 107:176.

Maquirriain J, Merello M. The athlete with muscular cramps: clinical approach. J Am Acad Orthop Surg 2007; 15:425.

American Academy of Sleep Medicine. Sleep related leg cramps. In: International classification of sleep disorders, 3rd ed., American Academy of Sleep Medicine, Darien, IL 2014. p.299-303.

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