You’re fast asleep when suddenly a sharp, painful cramp strikes your calf, forcing you to wake up and stretch your leg. If this sounds familiar, you’re not alone. Nighttime leg cramps are common, and although they’re usually harmless, frequent episodes may deserve more attention than you think. The important question is: what’s causing them to happen in the first place?

One possible factor is dehydration, particularly after exercise or during hot weather. Your muscles rely on a delicate balance of fluids and minerals to function properly, and disruptions can sometimes contribute to cramping. Muscle fatigue, prolonged standing, and sitting in the same position for hours may also increase the likelihood of these uncomfortable nighttime episodes.

However, dehydration isn’t always the answer. Certain medications and underlying health conditions, including diabetes, kidney disease, and nerve problems, may be associated with muscle cramps. Age can also play a role, as nighttime cramps become more common in older adults. If your cramps occur frequently, disrupt your sleep, or begin after starting a new medication, speaking with a healthcare professional can help identify possible causes.

The good news is that a few simple habits may help. Gentle calf stretches before bedtime, regular physical activity, and drinking enough water throughout the day are sensible starting points. When a cramp strikes, try gently straightening your leg and pulling your toes toward your shin. A light massage or a warm towel may also help relax the affected muscle. Avoid taking mineral supplements simply because you suspect a deficiency; they aren’t necessary for everyone.

But here’s what you shouldn’t ignore: cramps accompanied by significant swelling, redness, warmth, or persistent pain may indicate something more serious. Seek urgent medical assessment if these symptoms develop, particularly in one leg. Chest pain or sudden difficulty breathing alongside leg swelling requires emergency care. Most nighttime cramps are not dangerous, but recurring pain is worth discussing with your doctor—especially if it affects your sleep or daily life. Understanding the possible causes is the first step toward more comfortable nights.