A leg cramp is a sharp, sudden contraction or tightening of the muscle in the calf, which usually lasts a few seconds to a few minutes. If a cramp does hit, you can ease it in the moment by stretching the muscle gently. To find a long-term solution to leg cramps, however, you might need to take a closer look at their many potential causes.
- Dehydration: One of the classic causes of leg cramps is dehydration. “Athletes and avid exercisers deal with cramps all the time,” says Mark D. Peterson, PhD, research assistant professor in the department of physical medicine and rehabilitation at the University of Michigan Medical School, “especially during the summer months, in the heat without enough liquid.” The reason dehydration causes cramping is largely theoretical, says Todd J. Sontag, DO, family physician with Orlando Health Physician Associates. It may be that fluid depletion causes nerve endings to become sensitized, “triggering contractions in the space around the nerve and increasing pressure on motor nerve endings,” he says. RELATED: 14 Surprising Causes of Dehydration
- Mineral deficiency: It’s not just water that you sweat out. Lost electrolytes can also contribute to leg cramping. If you’re low in certain electrolytes and other minerals, that imbalance can trigger spontaneous cramping. An imbalance in sodium, calcium, magnesium, or potassium could all lead to leg cramping, says Gerardo Miranda-Comas, MD, associate program director of the sports medicine fellowship at the Icahn School of Medicine at Mount Sinai.
- Pregnancy: Pregnancy increases a woman’s risk for leg cramps, especially during the second and third trimesters. “This is most likely because the odds of magnesium and potassium deficiency are higher during pregnancy,” Peterson says. If you’re pregnant and experiencing leg cramps, stay hydrated and consider taking a magnesium supplement–with your doctor’s approval.
- Exercise intensity: When you’re trying to kick your routine up a notch–increasing your biking mileage, starting to swim for triathlon training–your muscles aren’t automatically used to the new intensity and movement. “Whenever cramps are induced by starting or restarting an exercise, that’s usually an indication of ‘too much, too soon,'” Dr. Miranda-Comas explains.
- Fatigue: You may be more prone to leg cramps when you’re already overtired. You might be more lax in your diet or forget to hydrate effectively, or, if your body hasn’t had enough time to properly recover from your last bout of exercise, your muscles might already be in rough shape. “Physiologically, when the muscle is fatigued, it’s not as synchronized in using nutrients,” Dr. Miranda-Comas says. In other words, a tired muscle loses more nutrients than it uses, so it’s not functioning at its peak.
- Sitting or standing: Muscles were made to move, contract, and rest, so if you’re doing anything out of the ordinary–sitting at a conference all day, standing in line at an amusement park–you might experience some leg cramping. Standing for a prolonged period of time can understandably contribute to muscle fatigue, which in turn can cause cramping, Dr. Sontag says. But too much sitting isn’t necessarily better. Prolonged sitting “may predispose the muscles to malfunction,” he explains, as the muscle fibres may become hyperactive.
- Medications: If there’s no obvious cause of your leg cramps, then you might want to take a look at any recent additions to your medication list, Dr. Sontag says. Diuretics, a class of medications used to lower blood pressure, may trigger cramps because they deplete the body of fluid and salts, he explains. Other medications that may cause leg cramps include osteoporosis drugs like raloxifene and teriparatide; intravenous iron sucrose (used to treat anaemia); asthma medications like albuterol; conjugated estrogens (used to treat menopause symptoms); and pain meds like naproxen and pregabalin.
- Peripheral artery disease: If your leg cramps seem spontaneous and not exercise-related, it’s important to see your doctor to rule out underlying concerns. Some, for instance, “those that affect how the body moves electrolytes,” Dr. Miranda-Comas says, can cause leg cramps. Others, like peripheral artery disease, when cholesterol clogs blood vessels in the legs, affect blood flow. PAD can trigger cramps since there may not be enough blood getting to the legs.
- Multiple sclerosis: Leg cramps can also be a symptom of the nervous system disorder multiple sclerosis. Some people with MS experience spasticity, which can include a range of involuntary muscle spasms and twitches, as well as leg cramps. Spasticity might feel like a mild tightness or tingling in the muscles to some people or more severe cramping and pain to others.
