Almost everyone gets a leg cramp — also called a charley horse — at some point or another. And an electrolyte imbalance is often to blame for these spasms, which is why taking potassium for leg cramps may help prevent pain.
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"Leg cramps develop as the result of sudden and involuntary contractions," says Robert Glatter, MD, an emergency physician with Lenox Hill Hospital in New York City. "They can be intensely painful due to lack of preparation for their movement or contraction."
But why exactly does potassium help with leg cramps? Here's everything you need to know about potassium for cramps, including whether bananas help with cramps.
Eating bananas for cramps won't cure the issue in the moment, but eating an electrolyte-rich diet that includes potassium may help prevent muscle spasms in general, per the Mayo Clinic.
Potassium and Leg Cramps
Many people attribute leg cramps to a lack of potassium, which is an electrolyte crucial to maintaining muscle functioning, per a January 2021 StatPearls article.
"It's not an unreasonable thing to look at as a potential culprit," says Vijay Jotwani, MD, a sports medicine primary care physician at Houston Methodist. In truth, though, experts don't really understand what causes leg cramps or a muscle spasm, he says.
That said, it's certainly possible (though not proven) that low levels of potassium are responsible, Dr. Glatter says. That's because the nutrient affects the transmission of nerve impulses and the contraction of muscles, so low levels of potassium in the blood — known as hypokalemia — can impair those functions, leading to symptoms like muscle weakness, twitching, cramps and fatigue, according to the Cleveland Clinic.
Common causes of low potassium levels include:
- Frequent vomiting or diarrhea from illness or laxative use
- Excessive sweating
- Drinking too much alcohol
- Drugs like diuretics, antibiotics and corticosteroids
- A potassium deficiency in your diet
- Underlying conditions like kidney disease or adrenal disorders
The reverse — high potassium levels — may also cause cramping, Dr. Glatter says.
Other Possible Causes of Leg Cramps
You don't have to be an endurance athlete to get leg cramps. In fact, muscle spasms don't just occur during exercise — random cramping or nighttime leg cramps can also occur due to potassium deficiency or these other common causes:
Potassium isn't the only electrolyte associated with muscle function. Others include sodium, calcium and magnesium, and they work much the same as potassium to help support your muscles, nerves, brain and heart, according to the U.S. National Library of Medicine.
But when you become dehydrated by losing fluids from sweating, vomiting, diarrhea or not drinking enough water, your electrolyte levels can dip and cause symptoms like muscle weakness, cramping or twitching, per the Cleveland Clinic.
"The muscles work as a grid. And when that grid comes together for a muscle contraction, it takes a chemical reaction — including water — for that grid to release and the muscle to open back up," Dr. Jotwani says. "Having water at the site of the muscle cells is important."
Exercise — especially in a hot environment — can deplete your muscles of that water, and is thus a common cause of muscle cramps, per the Mayo Clinic. That's why endurance athletes often sip sports drinks that supply potassium, magnesium and other electrolytes.
2. Skipping Your Warm Up
Not warming up enough before exercise or muscle fatigue due to overexertion can also cause leg cramping, as can muscle and nerve injury or compression of a spinal nerve, Dr. Glatter says.
3. Your Age
Age can also be a factor. For instance, middle-aged and older adults are more prone to nighttime leg cramps, according to the Cleveland Clinic.
If you drink plenty of water, stretch regularly, eat enough potassium and still have a problem with leg cramps, talk to your doctor to see if there's another factor contributing to your muscle pain.
Pregnancy can also contribute to muscle spasms. In fact, as many as 40 percent of pregnant people will experience leg cramps at night, likely due to the extra strain on their muscles from the added weight, according to the Cleveland Clinic.
5. Circulation Problems
Poor blood supply may also cause cramping, according to the Mayo Clinic. This symptom can be associated with underlying conditions like diabetes or a thyroid disorder. A more mundane reason? Flat arches, per the Cleveland Clinic.
Muscle cramps often go away on their own. But if the cramping is extremely painful, occurs often without an obvious cause or comes with additional symptoms like muscle weakness, swelling or a change in skin color, visit your doctor, according to the Mayo Clinic.
How to Treat and Prevent Leg Cramps
Leg cramps usually go away on their own in one or two minutes without any treatment, Dr. Glatter says. But there are certain things you can do to relieve the pain and spasms while they're happening, including:
1. Stretching and Massaging the Area
Dr. Jotwani recommends gently stretching and massaging the affected muscle. If you're prone to cramping in the middle of the night, Dr. Glatter suggests stretching your legs before you go to bed.
Some people also find that applying heat can be effective. "It may help loosen a tight muscle," Dr. Jotwani says.
2. Eat Potassium-Rich Foods
When it comes to potassium for leg cramps, eating a banana or another high-potassium food is unlikely to help a cramp that is already in process (though it won't hurt), Dr. Jotwani says. "It's an easy remedy to try and, if it helps, then fantastic," he says.
That said, getting enough potassium through your diet may help prevent future spasms. However, this is still unproven and it's thus not clear how much potassium should you take for leg cramps.
- People assigned female at birth: 2,600 mg
- People assigned male at birth: 3,400 mg
If you're eating a balanced diet full of whole foods, you shouldn't have much trouble getting the right potassium dosage for leg cramps (and life in general). But if you suspect that your muscle spasms are caused by an electrolyte imbalance, snack on more potassium-rich foods like:
- Fruit like bananas, melon and dried fruit like raisins and prunes
- Starchy vegetables like squash and potatoes
- Leafy greens like beet greens, spinach and Swiss chard
- Legumes like beans, peas and lentils
- Fish like salmon and tilapia
- Dairy products like milk and yogurt
Do Bananas Help With Leg Cramps?
Perhaps you've heard that bananas are good for leg cramps. While eating bananas for cramps won't get rid of a muscle spasm in the moment, eating bananas to prevent leg and other muscle cramps can't hurt, Dr. Jotwani says.
That's because the average banana supplies about 375 milligrams of potassium, per the U.S. Department of Agriculture. So if your diet is low in potassium, regularly eating bananas is one way to up your intake and potentially stave off muscle cramps to come.
3. Ask Your Doctor About a Supplement
It's best to stick to natural sources of the nutrient rather than relying on supplements. That's because the FDA doesn't require supplements to be proven safe or effective before they're sold, so there's no guarantee that any supplement you take is safe, contains the ingredients it says it does or produces the effects it claims.
But if you suspect your leg cramps are the result of an underlying potassium deficiency, visit your doctor to get a diagnosis. They may suggest you take a supplement to up your levels of the nutrient, per the Cleveland Clinic, and can recommend the best potassium supplement for leg cramps.
For instance, they can determine whether a potassium gluconate supplement may help treat leg cramps or other symptoms better than another form of the mineral, like potassium chloride, per the National Institutes of Health's Office of Dietary Supplements.
One of the best ways to prevent run-of-the-mill cramping and spasms is to improve your muscle strength and stamina through resistance exercising, Dr. Jotwani says. Focusing on strengthening the calf muscles, hamstrings and quadriceps may be especially helpful, per the AAOS.
5. Stay Hydrated
Make sure you drink lots of water before exercising, Dr. Glatter says. Water and other hydrating beverages like sports drinks contain electrolytes that can help replenish fluid lost through sweating.
You can also try less intense exercise for shorter periods of time or skip exercising in hot weather to avoid throwing your electrolytes out of whack from excessive sweating and exertion, per the Mayo Clinic.
The same goes for when you're sick or otherwise losing lots of bodily fluids — proper hydration can help keep your electrolyte levels stable and prevent side effects like cramping.
- American Academy of Orthopaedic Surgeons: “Muscle Cramps”
- Mayo Clinic: “Muscle Cramp”
- National Library of Medicine: “Muscle Cramps"
- Office of Dietary Supplements: “Potassium”
- StatPearls: "Potassium"
- Cleveland Clinic: "Low Potassium Levels in Your Blood (Hypokalemia)"
- U.S. Department of Agriculture and U.S. Department of Health and Human Services: "2020-2025 Dietary Guidelines for Americans"
- Mayo Clinic: "High potassium (hyperkalemia)"
- U.S. Department of Agriculture: "Bananas, ripe and slightly ripe, raw"
- Cleveland Clinic: "Electrolytes"
- Cleveland Clinic: "Flat Feet"
- FDA: “FDA 101: Dietary Supplements”
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.