I am regularly woken at night from a sound sleep because my hands have also gone to sleep. They become very heavy and numb and sometimes a little painful. I have to shake them around to get the feeling back. Why is this happening?
Numbness of the arms, hands, or fingers that comes on during sleep is another of those very annoying problems, like leg cramps at night, that become increasingly common as we age.
Unlike the leg cramps, which develop for reasons that are not clear to us, the immediate cause of the numbness is clear. It is not, as many people have asked me, due to poor circulation, but is caused by pressing on or stretching the nerve going to the area that becomes numb.
Many people have had the experience, even when young, of falling asleep with their arms behind their head, and awakening later with numbness in both arms. Holding the arms motionless behind the head has stretched the nerves that run down to the arms, interfering with their ability to conduct sensations, and that creates the numbness.
Another common type occurs when someone sleeps on their side with one or both hands up under their cheek. This bends the elbows close to their maximum and stretches the ulnar nerve where it loops around the elbow on the inside. This typically causes numbness running down the inside of the arm to the little finger, and perhaps the next two fingers.
Why are we being plagued by these things now, when we slept in all kinds of strange positions as children and never had this happen? As we age, our tissues become less resilient, less bouncy than children’s tissues. We tend to develop little, hard outgrowths on our bones that constrict or press on the nerves more easily. And probably our nerves are not as stretchy as those of children and tolerate that abuse less well.
Fortunately, this type of numbness, which disappears quickly as soon as one changes the position of the numb part, does not indicate serious illness or a stroke. The event that can be a precursor to a stroke is a transient ischemic attack or TIA, and this can cause temporary numbness, but it has nothing to do with sleep or the position of the limbs. TIAs may come on at any time, usually involve numbness of half the face or half the body, may last for minutes to hours, and do not go away promptly when one changes position.
So what about those night cramps, you’re saying? Can anything to be done about them? Again, they don’t indicate any serious problem, although we don’t know why people get them. They can often be controlled by taking a calcium supplement; I take two 600mg tablets of calcium carbonate with vitamin D at night to prevent the cramps I am otherwise prone to get. Taking them with food may increase the absorption. Drinking several glasses of milk daily may also be effective. Since almost all of us, and especially women need to be taking calcium supplements as we grow older, this should be part of our daily routine.