Possible Causes of Muscle Cramps

Rachel Despres

Published on October 18, 2017 Updated on March 24, 2020

Health Check Certified By: Patty Weasler, RN

Muscle cramps, which are often referred to as “charley horses,” are something that most everyone has experienced at one time or another. They most commonly occur in the calf or foot when the muscles involuntarily contract, becoming hard and painful.

In most cases, the cause of a muscle cramp is unknown; these are referred to as idiopathic leg cramps. Sometimes, however, muscle cramps occur due to an underlying medical condition or circumstance—such as these six.

1. Inadequate Blood Supply

With a condition known as peripheral arterial disease (also commonly referred to as arteriosclerosis of the extremities), the arteries become narrow or, in some cases, blocked.

The American Heart Association tells us that constriction causes poor blood flow to the legs and feet, leading to the most common symptom of peripheral artery disease, painful muscle cramps. The Mayo Clinic says these cramps most commonly occur while exercising, and will typically go away soon after you stop.

2. Nerve Compression

When the nerves in the spine become compressed, as is the case with a condition called lumbar stenosis, painful cramps in the legs can occur. The Mayo Clinic suggests “walking in a slightly flexed position — such as you would use when pushing a shopping cart ahead of you — may improve or delay the onset of your symptoms.”

Healthline adds that peripheral neuropathy—a disorder that occurs when the nerves in your peripheral nervous system “malfunction because they’re damaged or destroyed”—may also cause muscle cramps. This is especially likely to occur if it is the motor nerves that have been affected, and may also result in muscle weakness and twitching.

3. Mineral Depletion

Having too little calcium, potassium, or magnesium in the blood can also lead to muscle cramps, as low levels of these minerals “directly increase the excitability of both the nerve endings and the muscles they stimulate,” says MedicineNet.com.

The source adds that cramps can occur “in any circumstance that decreases the availability of calcium or magnesium in body fluids,” such as hyperventilation, excessive vomiting, or inadequate intake from one’s diet.

4. Dehydration

While engaging in physical exercise, the body can lose a lot of fluids through perspiration. If you’re not drinking enough water to compensate for this fluid loss, it can lead to dehydration, and dehydration can cause muscle cramps.

Medical News Today adds that “if conditions are warm and the athlete has sweated profusely and lost a lot of sodium (salt), the risk of developing a muscle cramp is greater.”

5. Certain Medications

Taking certain medications can also increase a person’s likelihood of having muscle cramps. According to WebMD, these medications can include antipsychotics, birth control pills, diuretics, statins, and steroids.

Diuretics, for instance, can cause cramps by “depleting body fluid and sodium,” says MedicineNet.com. The source adds that they also cause the loss of potassium, calcium and magnesium, which, as mentioned earlier, can lead to muscle cramps.

6. Strain or Injury

Among the most common causes of muscle cramps is strain. “If a muscle is placed under severe stress or used for a long time,” Medical News Today says, “a leg cramp may occur during the exertion or afterwards.” These types of cramps are more likely to occur in athletes or those who play a lot of sports.

Muscle cramps may also occur to protect an area of the body that has been injured, such as a broken bone, as the cramp “tends to minimize movement and stabilize the area of injury,” says MedicineNet.com.