Why Do My Hands and Feet Fall Asleep?

people sitting in office chairs with their legs crossed

If you have a habit of sitting on your feet or with your legs crossed, then you’re probably familiar with the concept of a body part “falling asleep.” It’s a strange feeling when a hand or foot (or a whole leg!) goes totally numb or tingly, but it’s usually nothing to be alarmed about. So, what causes this sensation? Hint: It’s not cutting off blood circulation, like many of us were told as kids.

A quick lesson on the peripheral nervous system

You can think of peripheral nerves as tiny wires running throughout your body. Their job is to carry signals from your brain to a distant body part (“Wiggle your toes!”) or from that body part to your brain (“Hey, this is hot!”). 

“Falling asleep”

Sometimes, when you sit on your foot or lie on your arm for too long, some of those nerves can get compressed and those signals back to your brain are cut off temporarily. Because your body part isn’t sending signals of what it’s feeling, your brain interprets this as the body part not feeling anything at all—numbness. The medical term for this is paresthesia.

Once you change positions and are no longer smashing those nerves, your body part starts to “wake up.” The sudden return to feeling often feels tingly or even painful—that “pins and needles” sensation.

Preventing paresthesia

The easiest ways to avoid the prickles are:

  • Don’t sit or lie down on a body part for long periods
  • Don’t cross your legs while sitting.
  • Get up and move, or at least change positions, if you have to sit all day.

When should I worry?

If you have numbness and/or tingling in your limbs that happens often, for no apparent reason, and lasts for more than just a few minutes, then it could be a sign of an underlying medical condition. Be sure and talk to your health care provider and explain your symptoms.