Life's Great Mysteries - What is that “pins and needles” feeling when part of your body goes to “sleep”?

We’ve all felt it, right? You sit in a position that causes extra pressure to your leg or arm. After a while, you lose feeling in that area. Then, when you move your extremity to relieve the pressure, you start to feel the “pin pricks.” What’s up with that?

First, the feeling is called paresthesia, and you may be surprised to learn it isn’t caused by blood circulation (a common misunderstanding). Instead, it’s caused by compressing the nerves for too long. Here’s how it works…

If you put excess pressure on an extremity, the nerves in that area stop transmitting signals to the brain. For a while, the nerves try to transmit signals, but when they don’t receive any feedback, they simply stop trying. Because those nerves are no longer sending signals to your brain, you perceive the area to be numb. Or you think, "My arm fell asleep." It’s somewhat disturbing because you experience difficulty using those muscles for a while, even to the point where you might fall down if your foot is asleep.

When the pressure on the nerves ends, the nerves can sense this, and they initiate a series of tests. They send out signals to all the neurons down the line, to make sure they are still there and are alive. The neurons respond with a jolt of pain… their way of saying, “Yes, I’m still here!” After thirty seconds to two minutes, our brain realizes everything is well, and it shuts off this firing pattern so it can resume its normal operations. You can usually speed up the recovery process by shaking or rubbing your arm or leg.

I hate it when my foot falls asleep during the day because that means it’s going to be up all night.

Photo Credits:
- Man experiencing paresthesia in the hand - DepositPhotos