Why does your foot tingle when it falls asleep?

When your foot "falls asleep," it's typically due to pressure on a nerve, which disrupts the normal flow of signals between the nerve and the brain. This pressure can restrict blood flow and lead to a temporary lack of sensation, causing the tingling or "pins and needles" feeling as the nerve starts to recover. Once you relieve the pressure, normal circulation and nerve function return, and the tingling sensation gradually fades.