A charley horse can jolt you awake with sharp, sudden pain, locking your calf and leaving you breathless. These nighttime muscle cramps are usually harmless, but they can wreck your sleep and leave your legs sore for hours. They happen most often in the calves, though feet and thighs can get hit too.

Dehydration and mineral imbalances are two of the biggest triggers. Not drinking enough water or having low magnesium, potassium, or calcium can make your muscles misfire. Overexertion—like intense workouts—and long periods of sitting or standing can also make cramps more likely once you finally rest.

Posture problems and nerve compression can play a role as well, and pregnancy or certain medications may increase the frequency of cramps. Even alcohol can contribute by dehydrating the body. In more serious cases, frequent cramps may signal underlying conditions like diabetes or thyroid issues.

When a cramp strikes, stretching, massaging the muscle, or using heat can bring quick relief. Staying hydrated and maintaining balanced electrolytes can help prevent future episodes. With a few small habits, you can make those painful midnight jolts far less common.