Charley Horse: What It Is and How to Prevent It

Updated: Apr. 15, 2021

A Charley horse can strike anyone at any time, but some people may be more likely to experience these painful muscle spasms. Here's what causes Charley horses and how to prevent them.

woman sitting on couch holding her leg in painAndreyPopov/Getty Images

What is a Charley horse?

If you have ever had an incredibly painful leg cramp come on fast and furiously you have likely experienced a Charley horse. This type of muscle spasm tends to occur when a muscle is overused or injured, and can sometimes strike in the middle of the night. Ouch!

But what exactly causes a Charley horse, and maybe even more importantly, why does such a painful experience have such a funny name? There are several tales about how the cramps might have gotten their name and they all center around baseball.

In 1886, a West Virginia newspaper called the Wheeling Daily Intelligencer reported on a new athlete malady. “Base-ballists invented a brand new disease called ‘Charley horse.’ It consists of a peculiar contraction and hardening of the muscles and tendons of the thigh, to which ball players are liable from the sudden starting and stopping in chasing balls.” A ballplayer named Jack Glasscock was said to have originated the name, “because the way the men limped around reminded him of an old horse he once owned named Charley.”

Another story credits player Joe Quest, son of a blacksmith, for saying injured players were limping around like Charley, an old horse at his father’s shop. Still other stories say many ballparks had old workhorses that pulled equipment and they were often named Charley, says The New Dickson Baseball Dictionary.

Whatever the origin of the name, the origin of the cramps are the same.

“The spasms are the result of involuntary muscle contractions,” explains Robert Glatter, MD, an emergency physician at Lenox Hill Hospital in New York City and a former sideline physician for the NFL’s New York Jets.

Charley horses can last for minutes, hours, or days. They can strike anywhere in the body, but the most common spots are the back of your lower leg/calf, back of your thigh, or the front of your thigh. (Here’s what else could be causing your calf pain.)

Common causes of Charley horses

Exactly what causes a Charley horse is not known, but common triggers include muscle injury, overuse or strain from vigorous exercise, not stretching before or after working out, exercising in extreme heat or cold, and/or dehydration, Dr. Glatter says.

Lack of blood flow to a specific muscle group and low levels of sodium, calcium, potassium, or other electrolytes may also contribute to the risk of developing a Charley horse, he says. Electrolytes are minerals—sodium, potassium, chloride, magnesium, calcium, phosphate, bicarbonate—that dissolve in your body’s fluids, creating electrically charged ions that affect how your body functions. (Do you think you might have an electrolyte imbalance? Here’s how to tell.)

“Nerve compression due to a herniated disc in your back may also be contributory,” he says. The slipped disc causes a pinched nerve that results in the calf cramp.

And of course you can also develop a Charley horse while sleeping, and the pain may even wake you up.

Charley horse risk factors

Some people may be more likely to develop a Charley horse than others. Risks include smoking, obesity, taking water pills or diuretics, and/or drugs called statins to lower cholesterol, Dr. Glatter says.

“Athletes tend to get them more frequently as a result of muscle fatigue from overuse,” he says. “Obese people may have inadequate circulation to the lower extremities.”

Getting a Charley horse is also very common in pregnancy, especially during the second and third trimester, adds Dominic King, DO, a sports medicine and intervention orthopedic physician at the Cleveland Clinic in Ohio. “This is because of reduced circulation in your legs from pressure of the baby on blood vessels or rapid change in weight associated with pregnancy.”

Other diseases that cause abnormalities in electrolytes such as liver disease or thyroid disease may also increase your risks of developing a Charley horse cramp, he says. The older you are, the greater your chances, too. “As we age we have reduced muscle mass, and the muscle that is there can be easily overstretched,” Dr. King says.

close up of man with pain in leg while exercising outsideProstock-Studio/Getty Images

Treating Charley horses

There are things you can do in the moment to reduce the pain of a Charley horse.

“Try to massage the tight area gently or put some pressure or weight on the affected leg in a gentle stretch,” says Tina Castiello, a physical therapist at the Hospital for Special Surgery in New York City.

Gentle is the key, she says. “If you stretch too hard, you will make the cramp worse.”

Warm compresses or water will relax the muscle, she adds. “If it is sore following the cramp, use ice.”

How to prevent a Charley horse

Prevention is important when it comes to these cramps, says Jennifer Beck, MD, an orthopedic surgeon at UCLA Health in Los Angeles. “Make sure you do a proper warm-up and cooldown before and after exercise,” she suggests. Focus on your hamstring and quad muscles. (Need tips? Try these warm-up exercises.)

“Staying hydrated with plain water and/or electrolyte replacement drinks like Gatorade can also prevent Charley horse,” she says.

Dr. King encourages people who have had surgery to keep up with their physical therapy and home exercise regimens. “This way your muscles won’t become weak and more likely to Charley horse when you use them,” she says.

Certain medications and conditions may affect your electrolyte balance, Dr. King adds. If you are prone to getting cramps, ask your doctor if you should take a multivitamin based on your health history.

If you tend to get Charley horses when you are sleeping, stretch your calf muscles and drink a glass of water before bed to help prevent dehydration, Castiello adds. Here are some calf stretches you can try.

When to be concerned

The good news is that a Charley horse is rarely anything serious, Dr. King says. “Cramps in isolation are not too worrisome but if they travel with low back pain it could be a sign of a pinched nerve,” he says.

Swelling and redness in the calf with cramping can be a sign of a potentially life-threatening deep vein thrombosis (DVT) and needs to be evaluated immediately, Dr. King stresses.

“Cramps plus another symptom is when I start to get a little more worried,” he says.

You should also see a doctor if your Charley horses are frequent, prolonged, severe, and occur in multiple parts of your body, Castiello adds. “A Charley horse every once in a while that you can relate back to exercising or exercising in extreme weather is likely not worrisome, but if you can’t find a reason for it and they are happening weekly or more than once a week, see a doctor as there may be something else going on.”