Few things are more annoying or painful than a charley horse  in the middle of the night. Your calf feels like a huge knot, often your toes are frozen, and it can take a long time for those muscles to relax.
There are a variety of causes, especially when we get them during the night. For older people, the cause can be poor circulation, says Lori Thein Brody . She is a physical therapist and athletic trainer with the UW Sports Medicine and Spine Center. Brody explains that the generally stable position that we stay in overnight can increase the impact of that lack of circulation and cramps occur. She advises that hanging your legs over the side of the bed can help with those. While these can occur during the night like a charley horse, they feel quite different.
Jill Thein-Nissenbaum  is an Assistant Professor in the Doctor of Physical Therapy Program at UW-Madison and a staff physical therapist for UW Athletics and Badger Sports medicine. She adds that dehydration is the most common culprit, especially with cramps in the calf muscle. Low potassium intake can also exacerbate those pains.
While we think of them as being in our legs, and particularly our calves, they can also happen in other areas, including our hands. Those pains can be circulatory or related to the nerves, often because of the position of the elbow and wrist while sleeping. Even the weight of gravity can contribute to cramps, so focusing on proper position, like keeping your elbow straight, or resting your arm on a pillow, can help.
A caller identifying himself as Doug from Jefferson experiences hand cramps regularly, and it appears to be from a form of dehydration. He says that as a kidney dialysis patient, at times they withdraw too much fluid in the process, and him hands will soon cramp up painfully. He will occasionally get them in the hamstring, groin or back as well.
While charley horses and other leg cramps are rarely the first sign of a more serious condition like diabetes or circulatory issues, if they are frequent and severe, they are certainly worth mentioning to a doctor. And if you focus on better positioning when sleeping and don’t see any improvement, that’s worth noting, too.
Both Brody and Nissenbaum agreed with a listener who identified himself as Sol from Stevens Point. Sol said, “Here is the trick for relieving cramps: voluntarily contract the opposing muscle to the cramping muscle and the cramp will immediately stop for as long as you hold the contractions. If the hamstrings cramp, contract the quads and hold. If the calf cramps, use your shin muscles to pull up your foot. If a hand cramp curls the hand, extend the hand and hold.” Nissenbaum cautioned, however, that it can be difficult in the middle of the night, when you’re in pain, to figure out exactly which is the opposite muscle.
Many callers shared some folk remedies that they swear by. A listener identifying herself as Bobbi from Stoughton said, “I have something that works well for me when I have a leg cramp. I heard it on public radio years ago. Right away when you feel the pain you grab your upper lip and pinch the sides of your lips together "pinching" the lip as hard as you could stand. You will immediately feel the cramp loosen. I hold the pinch until the cramp is completely gone.” Interestingly, several other listeners agreed that they’ve used that technique successfully.
Other ideas included a widely held idea that a bar of Ivory soap tucked in the bed sheets helps, although no one seems to know why. A listener identifying herself as Amy in Appleton shared that her grandmother recommended 2 tablespoons of white vinegar taken orally. She swears that “It works for leg cramps every time!”
One of the most often suggested remedies was drinking tonic water with quinine. That idea has more than a ring of truth, since quinine used to be prescribed medically for leg cramps, in addition to being an anti-malarial. But the Food and Drug Administration  issued a warning  last year about the use of prescription quinine for cramps.