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Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• Muscle cramps facts
• What are muscle cramps?
• What are the types and causes of muscle cramps?
• Do all muscle cramps fit into the above categories?
• Can medications cause muscle cramps?
• Can vitamin deficiencies cause muscle cramps?
• Can poor circulation cause muscle cramps?
• What are the symptoms of common muscle cramps? How are muscle cramps diagnosed?
• What is the treatment of skeletal muscle cramps?
• How can muscle cramps be prevented?
• Are there particular concerns for older adults?
• Are there medications to prevent muscle cramps?
• What is the prognosis of recurrent muscle cramps?
• Patient Comments: Muscle Cramps - Effective Treatments
• Patient Comments: Muscle Cramps - Vitamins and Supplements
• Patient Comments: Muscle Cramps - Prevention
• Patient Comments: Muscle Cramps - Causes
• Muscle Cramps Index

Activity: Authorities recommend stretching before and after exercise or sports, along with an adequate warm-up and cooldown, to prevent cramps that are caused by vigorous physical activity. Good hydration before, during, and after the activity is important, especially if the duration exceeds one hour, and replacement of lost electrolytes (especially sodium and potassium, which are major components of perspiration) can also be helpful. Excessive fatigue, especially in warm weather, should be avoided.

How much should I drink?

Hydration guidelines should be individualized for each person. The goal is to prevent excessive weight loss (>2% of body weight). You should weigh yourself before and after exercise to see how much fluid you lose through sweat. One liter of water weighs 2.25 pounds. Depending on the amount of exercise, temperature and humidity, body weight, and other factors, you can lose anywhere from approximately .4 to 1.8 liters per hour.

Pre-exercise hydration (if needed):

1. 0.5 liters per hour for a 180-pound person several hours (three to four hours) prior to exercise.

2. Consuming beverages with sodium and/or small amounts of salted snacks or sodium-containing foods at meals will help to stimulate thirst and retain the consumed fluids.

During exercise:

1. Suggested starting points for marathon runners are 0.4 to 0.8 liters per hour, but again, this should be individualized based on body weight loss.

2. There should be no more than 10% carbohydrate in the beverage, and 7% has generally been considered close to optimal. Carbohydrate consumption is generally recommended only after one hour of exertion.

3. Electrolyte repletion (sodium and potassium) can help sustain electrolyte balance during exercise. Particularly when


• there is inadequate access to meals or meals are not eaten,



• physical activity exceeds four hours in duration,
  
  
• during the initial days of hot weather.

Under these conditions, adding modest amounts of salt (0.3 g/L to 0.7 g/L) can offset salt loss in sweat and minimize medical events associated with electrolyte imbalances (for example, muscle cramps, hyponatremia).

Post-exercise:

1. Drink approximately 0.5 liters of water for every pound of body weight lost.

2. Consuming beverages and snacks with sodium will help expedite rapid and complete recovery by stimulating thirst and fluid retention.

Pregnancy: Supplemental calcium and magnesium have each been shown to help prevent cramps associated with pregnancy. An adequate intake of both of these minerals during pregnancy is important for this and other reasons, but supervision by a qualified health care professional is essential.

Dystonic cramps: Cramps that are induced by repetitive non-vigorous activities can sometimes be prevented or minimized by careful attention to ergonomic factors such as wrist supports, avoiding high heels, adjusting chair position, activity breaks, and using comfortable positions and equipment while performing the activity. Learning to avoid excessive tension while executing problem activities can help. However, cramps can remain very troublesome for activities that are difficult to modify, such as playing a musical instrument.

Rest cramps: Night cramps and other rest cramps can often be prevented by regular stretching exercises, particularly if done before going to bed. Even the simple calf-stretching maneuver (described in the first paragraph of the section on treatment), if held for 10 to 15 seconds and repeated two or three times just before going to bed, can be a great help in preventing nocturnal cramps. The maneuver can be repeated each time you get up to go to the bathroom during the night and also once or twice during the day. If nocturnal leg cramps are severe and recurrent, a foot board can be used to simulate walking even while recumbent and may prevent awkward positioning of the feet during sleep. Ask your doctor about this remedy.

Another important aspect of prevention of night cramps is adequate calcium and magnesium. Blood levels may not be sensitive enough to accurately reflect what is happening at the tissue surfaces where the hyperexcitability of the nerve occurs. Calcium intake of at least 1 gram daily is reasonable, and 1.5 grams may be appropriate, particularly for women with or at risk for osteoporosis. An extra dose of calcium at bedtime may help prevent cramps.

Supplemental magnesium may be very beneficial for some, particularly if the person has a magnesium deficiency. However, added magnesium can be very hazardous for people who have difficulty eliminating magnesium, as happens with kidney insufficiency. The vigorous use of diuretics usually increases magnesium loss, and high levels of calcium intake (and therefore of calcium excretion) tend to increase magnesium excretion. Magnesium is present in many foods (greens, grains, meat and fish, bananas, apricots, nuts, and soybeans) and some laxatives and antacids, but a supplemental dose of 50-100 milligrams of magnesium daily may be appropriate. Splitting the dose and taking a portion several times during the day minimizes the tendency to diarrhea that magnesium can cause.

Vitamin E has also been said to help minimize cramp occurrence. Scientific studies documenting this effect are lacking, but anecdotal reports are common. Since vitamin E is thought to have other beneficial health effects and is not toxic in usual doses, taking 400 units of vitamin E daily is approved, recognizing that documentation on its effect on cramps is lacking.