MadSci Network: General Biology |
Dear Meturek, Thank you for your very interesting question. As I’m sure you have noticed, arms or legs usually "fall asleep" when they are squeezed under your body. Typical examples include sitting on the floor with your leg under you, or sleeping on your arm. When you squeeze your arm or leg like this, you temporarily compress, or squash, the nerves in that part of the body. Nerves are like little wires that allow your brain to communicate with the rest of your body. When they are squashed, the brain "loses communication" and the result is that you don’t feel anything in the part that is squashed. After a while, you will feel a little "tingling sensation", that appears to protect your nerves from damage! Sitting on your nerves for 10 minutes is not a problem, but imagine squashing them for 8 hours! When you finally change your position and release the nerves, they "wake up", and sensation comes back gradually with an annoying "needles and pins" sensation. It is possible that you also cut blood circulation in your arm and leg. Although this is not the main cause of the "falling asleep", it can contribute to the problem because your nerves need blood, or more precisely the oxygen that the blood carries, to function properly. Don’t be worried about your arms and legs falling asleep. It happens to everyone and it’s not dangerous. If you don’t like that weird, tingling feeling or even worse the needles and pins, just avoid squashing your nerves! I hope this answers your question. Cheers ! Benoit
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