What really happens when our feet or hands fall asleep? What really happens when our feet or hands fall asleep?

Paresthesia is the name for the tingling or numb sensation that we feel in our legs or arms after strong pressure has been placed on them for a long period of time. 

This condition is most common when we fall asleep on top of an arm or when we sit on top of a leg for a long period of time. When we go to move this limb, it has either lost its strength, is numb, has a tingling sensation and in many cases, cannot be felt at all.

While the explanation for what causes this type of condition is often a lack of circulation due to a blocked vein or artery, this is not actually true. What actually happens, is that pressure on a nerve prevents signals from circulating through it. This is not a serious problem, however, as the U.S. National Institute of Neurological Disorders and Stroke explains, “This feeling disappears quickly once the pressure has been released.”

If paresthesia (the numbing of different parts of the body) is chronic, occurs without placing any pressure on the limb, and is also a painful, this may be a sign of a neurological disorder or of an injured nerve, such as that which is caused by carpal tunnel.