A muscle cramp is an involuntarily and forcibly contracted muscle that does not relax. When we use the muscles that can be controlled voluntarily, such as those of our arms and legs, they alternately contract and relax as we move our limbs. Muscles that support our head, neck, and trunk contract similarly in a synchronized fashion to maintain our posture. A muscle (or even a few fibers of a muscle) that involuntarily (without consciously willing it) contracts is in a "spasm." If the spasm is forceful and sustained, it becomes a cramp. Muscle cramps cause a visible or palpable hardening of the involved muscle.
Muscle cramps can last anywhere from a few seconds to a quarter of an hour or occasionally longer. It is not uncommon for a cramp to recur multiple times until it finally goes away. The cramp may involve a part of a muscle, the entire muscle, or several muscles that usually act together, such as those that flex adjacent fingers. Some cramps involve the simultaneous contraction of muscles that ordinarily move body parts in opposite directions.
Cramps are extremely common. Almost everyone (one estimate is about 95%) experiences a cramp at some time in their life. Cramps are common in adults and become increasingly frequent with aging. However, children also experience cramps.
How can muscle cramps be prevented?
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,
or 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.
Muscle cramps can last anywhere from a few seconds to a quarter of an hour or occasionally longer. It is not uncommon for a cramp to recur multiple times until it finally goes away. The cramp may involve a part of a muscle, the entire muscle, or several muscles that usually act together, such as those that flex adjacent fingers. Some cramps involve the simultaneous contraction of muscles that ordinarily move body parts in opposite directions.
Cramps are extremely common. Almost everyone (one estimate is about 95%) experiences a cramp at some time in their life. Cramps are common in adults and become increasingly frequent with aging. However, children also experience cramps.
How can muscle cramps be prevented?
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,
or 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.
