Most people know the pain of a muscle cramp or “charley horse.” Muscle cramps are involuntary muscle contractions. They are common. But even though they can be quite painful, they don’t usually cause damage.
A muscle cramp is a sudden and involuntary contraction of one or more of your muscles. If you’ve ever been awakened in the night or stopped in your tracks by a sudden charley horse, you know that muscle cramps can cause severe pain. Though generally harmless, muscle cramps can make it temporarily impossible to use the affected muscle.
Muscle cramps result in continuous, involuntary, painful, and localized contraction of an entire muscle group, individual single muscle, or select muscle fibers. Generally, the cramp can last from minutes to a few seconds for idiopathic or known causes with healthy subjects or in the presence of diseases. Palpating the muscle area of the cramp will reveal a knot. Exercise-associated muscle cramps are the most frequent condition requiring medical/therapeutic intervention during sports.
The specific etiology is not well understood and possible causes depend on the physiological or pathological situation in which the cramps appear. It is important to note that a painful contraction that is limited to a specific area does not mean that the cause of the onset of the cramp is necessarily local. This activity highlights the importance of collaboration and communication among the interprofessional team members to improve outcomes for patients suffering from muscle cramps.
Long periods of exercise or physical labor, particularly in hot weather, can lead to muscle cramps. Some medications and certain medical conditions also may cause muscle cramps. You usually can treat muscle cramps at home with self-care measures.
What Are Muscle Cramps?
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 often 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 resolves. 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.
Muscle cramps are extremely common. Almost everyone (one estimate is about 95%) experiences a cramp at some time in their life. Muscle cramps are common in adults and become increasingly frequent with aging. However, children also experience cramps of muscles.
Any of the muscles that are under our voluntary control (skeletal muscles) can cramp. Cramps of the extremities, especially the legs and feet (including nocturnal leg cramps), and most particularly the calf (the classic “charley horse”), are very common. Involuntary muscles of the various organs (uterus, blood vessel wall, bowels, bile and urine passages, bronchial tree, etc.) are also subject to cramps. Cramps of the involuntary muscles will not be further considered in this review. This article focuses on cramps of skeletal muscle.
Muscle cramps range in intensity from a slight tic to agonizing pain. A cramping muscle may feel hard to the touch and/or appear visibly distorted or twitch beneath the skin. A cramp can last a few seconds to 15 minutes or longer. It might recur multiple times before it goes away.
The most common causes of muscle cramps are
- Benign leg cramps that occur for no known reason, typically at night
- Exercise-associated muscle cramping (cramping during or immediately after exercise)
Muscle cramps (also called charley horses) often occur in healthy people, usually in middle-aged and older people but sometimes in younger people. Cramps tend to occur during or after vigorous exercise but sometimes occur during rest. Some people have painful leg cramps during sleep. Sleep-related leg cramps usually affect the calf and foot muscles, causing the foot and toes to curl downward. Although painful, these cramps are usually not serious and are thus called benign leg cramps.
Almost everyone has muscle cramps at some time, but certain conditions increase the risk and/or severity of cramps. They include the following:
- Having tight calf muscles, which may be caused by not stretching, inactivity, or sometimes repeated accumulation of fluid (called edema) in the lower leg
- Becoming dehydrated
- Having low levels of electrolytes (such as potassium , magnesium , or calcium ) in the blood
- Having a nerve disorder or an underactive thyroid gland (hypothyroidism )
- Taking certain drugs
Low electrolyte levels may result from use of some diuretics, alcoholism, certain hormonal (endocrine) disorders, vitamin D deficiency , or conditions that cause loss of fluids (and thus electrolytes). Electrolyte levels may become low late in pregnancy.
Cramps can occur shortly after dialysis , possibly because dialysis removes too much fluid from the body, removes the fluid too quickly, and/or lowers electrolyte levels.
Disorders that cause similar symptoms
Some disorders cause symptoms that resemble muscle cramps.
Dystonias are involuntary muscle contractions, but they usually last longer and occur more often than cramps. Also, they tend to affect other muscles and may affect many other muscles, including any limb muscles as well as those of the back, neck, and voice. In contrast, benign leg cramps and exercise-associated muscle cramping tend to affect the calf muscles.
Tetany is continuous or periodic spasms of muscles throughout the body. These spasms usually last much longer than muscle cramps and are more widespread. The muscles may also twitch.
Illusory muscle cramps occur in some people. These people feel as if they are having cramps but no muscle contraction occurs.
Hardening of the arteries in the legs (peripheral arterial disease) may cause calf pain (claudication ) during physical activity such as walking. This pain is due to inadequate blood flow to muscles, not to muscle contraction as occurs with cramps.
Muscle cramps are usually harmless and don’t require medical attention. However, you should see a doctor if your muscle cramps are severe, don’t improve with stretching, or persist for a long time. This could be a sign of an underlying medical condition.
To learn the cause of muscle cramps, your doctor will perform a physical examination. They may ask you questions, such as:
- How often do your muscle cramps occur?
- Which muscles are affected?
- Do you take any medications?
- Do you drink alcohol?
- What are your exercise habits?
- How much liquid do you drink on a daily basis?
You may also need a blood test to check the levels of potassium and calcium in your blood, as well as your kidney and thyroid function. You may also take a pregnancy test.
Your doctor may order an electromyography (EMG). This is a test that measures muscle activity and checks for muscle abnormalities. An MRI may also be a helpful test. It’s an imaging tool that creates a picture of your spinal cord.
On occasion, a myelogram, or myelography, another imaging study, might be helpful.
Let your doctor know if you’re experiencing weakness, pain, or a loss of sensation. These symptoms can be signs of a nerve disorder.
How Can You Stop A Muscle Cramp When It Happens?
You may need to try several different ways to stop a muscle cramp before you find what works best for you. Here are some things you can try:
- Stretch and massage the muscle.
- Take a warm shower or bath to relax the muscle. A heating pad placed on the muscle can also help.
- Try using an ice or cold pack. Always keep a cloth between your skin and the ice pack.
- Take an over-the-counter pain medicine, such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Aleve). Be safe with medicines. Read and follow all instructions on the label.
- If your doctor prescribes medicines for muscle cramps, take them exactly as prescribed. Call your doctor if you have any problems with your medicine.
- Drink plenty of fluids. Sports drinks, such as Gatorade, will often help leg cramps.
Here are some things you can try for a leg cramp:
- Walk around, or jiggle your leg.
- Stretch your calf muscles. You can do this stretch while you sit or stand:
- While sitting, straighten your leg and flex your foot up toward your knee. It may help to place a rolled towel under the ball of your foot and, while holding the towel at both ends, gently pull the towel toward you while keeping your knee straight.
- While standing about 0.5 m (2 ft) from a wall, lean forward against the wall. Keep the knee of the affected leg straight and the heel on the ground. Do this while you bend the knee of the other leg. See a picture of how to do this calf stretch.
If you think a medicine is causing muscle cramps:
- Before you take another dose, call the doctor who prescribed the medicine. The medicine may need to be stopped or changed, or the dose may need to be adjusted.
- If you are taking any medicine not prescribed by a doctor, stop taking it. Talk to your doctor if you think you need to continue taking the medicine.
Prevention of Muscle Cramps
Measures to prevent cramps include the following:
- Not exercising immediately after eating
- Gently stretching the muscles before exercising or going to bed
- Drinking plenty of fluids (particularly beverages that contain potassium) after exercise
- Not consuming stimulants (eg, caffeine, nicotine, ephedrine, pseudoephedrine)
- Not smoking
The runner’s stretch is most useful. A person stands with one leg forward and bent at the knee and the other leg behind and the knee straight―a lunge position. The hands can be placed on the wall for balance. Both heels remain on the floor. The knee of the front leg is bent further until a stretch is felt along the back of the other leg. The greater the distance between the two feet and the more the front knee is bent, the greater the stretch. The stretch is held for 30 sec and repeated 5 times. The set of stretches is repeated on the other side.
Most of the drugs often prescribed to prevent cramps (eg, calcium supplements, quinine, magnesium, benzodiazepines) are not recommended. Most have no demonstrated efficacy. Quinine has been effective in some trials but is no longer recommended because of occasional serious side effects (eg, arrhythmias, thrombocytopenia, thrombotic thrombocytopenic purpura [TTP] and hemolytic-uremic syndrome [HUS], severe allergic reactions). Mexiletine sometimes helps, but whether using it is worth the risk of adverse effects is unclear. These effects include nausea, vomiting, heartburn, dizziness, and tremor.
Some athletic coaches and physicians recommend pickle juice for muscle cramping, but data concerning its efficacy are insufficient.