What Causes Leg Cramps

What Causes Leg Cramps

Leg cramps: They’re painful, annoying, and often strike when you least want them to — like during a workout or snooze-fest.

Here, we go into the common causes of leg cramps, and how to get rid of them when they hit.


What Are Leg Cramps?

Leg cramps — also known as muscle spasms — are usually harmless, and characterized by sudden involuntary muscle contractions in the quads, hamstrings, and/or calves.

“It feels like somebody’s jabbing you with a hot poker and you can’t get the muscle to relax,” says Michael Jonesco, D.O., sports physician at The Ohio State University Wexner Medical Center.

These uncomfortable, often-painful muscle spasms can last anywhere between a few seconds and 15 minutes, according to the Cleveland Clinic.

There are two different types of leg cramps:

  • Nocturnal leg cramps, which strike at night (usually in the calves).
  • Exercise-associated leg cramps, which happen during… you guessed it, exercise.

woman sitting down on steps in pain from leg cramps

What Causes Leg Cramps?

The cause of your leg cramps depends on whether they’re nocturnal or exercise-associated.

Nocturnal leg cramps

Though the exact causes aren’t well-understood, nocturnal leg cramps typically have to do with motor neurons (nerve cells that tell your muscles to contract) misfiring and telling your muscles to contract uncontrollably.

Anyone can experience leg cramps at night — up to 60 percent of adults have felt the sting of nocturnal leg cramps — and the longer you’re immobile, the more likely they are to hit.

That said, some people are more likely to get them than others, including:

  • Pregnant women
  • Children
  • People with nerve disorders
  • People over the age of 50

For example, research shows that up to 33 percent of people over the age of 50 experience nocturnal leg cramps.

According to a 2012 study, certain medications and medical conditions may also make you more prone to nocturnal leg cramps. These include:

  • Naproxen (Aleve is one common brand)
  • Teriparatide (a medication to treat osteoporosis)
  • Heart disease and cancer treatments

Exercise-associated leg cramps

Exercise-associated leg cramps, on the other hand, are common among runners, athletes, and anyone who performs repetitive movements or exercises in the heat.

When leg cramps hit during a workout, you can probably blame overexertion, heat, dehydration, and/or lack of fuel (food).

Any of these factors can interfere with your body’s ability to complete the workout by depleting your muscles’ energy stores of adenosine triphosphate (ATP), or limiting the amount of energy available.

“Exercise-associated muscle cramps typically have more to do with the muscle being exhausted and not having enough energy in the cell to maintain function,” Jonesco says.

When your muscles run out of energy, your cells start to misfire, causing your muscles to cramp or spasm uncontrollably.

Dehydration, for example, can interfere with the flow of blood and nutrients that go in and out of your muscles.

“When you can’t deliver adequate energy or remove waste from the muscle, it becomes more irritable,” Jonesco explains.

woman stopped from running due to leg cramps

How to Get Rid of Leg Cramps

As nocturnal and exercise-associated leg cramps have different triggers, you’ll want to tackle them in different ways.

Treating nocturnal leg cramps

If you’re regularly bothered with nocturnal leg cramps, you’ll want to chat with your doctor. If you take any medications or you’ve been diagnosed with a medical condition, your doctor may be able to suggest a change in treatment.

You can also try stretching before you go to bed. One study found this helped reduce the frequency and severity of nocturnal leg cramps in the over-55 crowd.

Treating exercise-associated leg cramps

When leg cramps hit during a workout, there are a few strategies you can try to find temporary relief. Unfortunately, you may not be able to bounce back right away, and you may be prone to more cramping episodes during your workout.

Ease up

If you get leg cramps during a workout, the best strategy is to dial back your exercise intensity, or stop altogether, Jonesco says.


Stretching out and/or massaging the muscle may help ease leg cramps when they strike, Jonesco says. Though stretching out a muscle is often the last thing you want to do when it’s cramping, research suggests this is the most effective treatment for immediate relief.

Pickle juice

Another strategy you can try: Drink pickle juice. Yes, it sounds strange, but one study suggests that taking small sips of pickle juice can relieve muscle cramps less than one minute after drinking. If you’re often bothered by leg cramps during a run or workout, try carrying a bottle of pickle juice with you to see if it helps.


However, the smartest approach for tackling exercise-associated leg cramps is to focus on prevention.

“The best thing you can do is make sure you stay hydrated prior to working out and providing fuel, or proper nutrition after your workouts,” Jonesco says.

Hydration and proper nutrition are especially important if you’re planning a long or intense workout, or if you’ll be exercising in the heat.

Finally, be sure your muscles are primed and warm before every workout. Steer clear of static stretches pre-workout and instead opt for dynamic stretches, Jonesco says. Then, perform passive stretches and foam rolling after your workout to ensure you keep fluids circulating in and out of your muscles.