We’ve all been there. You awaken in the morning and one of your hands is completely numb. It feels dead, heavy, and simply won’t work. Perhaps there’s some tingling as well. Or, you arise from a long dinner or movie and one of your legs feels that way. Then over a few minutes — maybe you shook your hands, stamped your foot — everything goes back to normal. Until the next time.
The first time this happened, it might have been worrisome. Now that you know it’s temporary and happens to everyone, it may not bother you. But did you ever wonder why in the world this happens? Read on!
When the nerves are not happy
When someone complains to me about their hand or leg falling asleep, I reassure them. I usually explain, “The nerves are not happy.” In general, numbness, tingling, and other symptoms called paresthesia are most commonly due to abnormal nerve function. And when this is intermittent, temporary, and related to holding one position for a long time, it’s rarely anything to worry about. The cause in these cases is simply pressure on one or more nerves traveling into the hands or feet. When you remove the pressure (by changing position, for example), the problem goes away.
However, many other causes of nerve problems — more than 100, in fact — can cause similar, though more prolonged and persistent, symptoms, as noted below. If you have one of these conditions, you’re far from alone: an estimated 20 million people have a form of peripheral neuropathy that might make hands or feet numb or tingly.
A word on nerve terminology
So, what is peripheral neuropathy? It’s worth clarifying some commonly used medical terms.
- Neuropathy means nerve disease.
- Peripheral neuropathy is a condition affecting nerves in the peripheral nervous system, which includes nerves outside of the brain and spinal cord. Nerves of the legs and arms are part of the peripheral nervous system, and tend to be the first ones affected by diseases of peripheral nerves.
- Compression (or entrapment) neuropathy develops because of pressure on a nerve. Carpal tunnel syndrome, which occurs when a nerve becomes compressed in an already tight channel in the wrist, is one well-known example. Having your hand or foot fall asleep is another. Fortunately, this is quite temporary, while carpal tunnel syndrome is often chronic.
- Paresthesia is a sensation of pins and needles, numbness, or another abnormal sensation, often tied to peripheral neuropathy. Having your hand or foot fall asleep is a temporary paresthesia.
When to see your doctor
If you’re hands or feet fall asleep occasionally and normal sensation quickly returns, that’s fine. No need to contact your doctor.
But call your doctor promptly if you have persistent nu