My hands and arms seem to fall asleep while i am sleeping,a couple times i have had to get up out of bed and wake my hand up. Also when i drive my vehicle i can not keeo my one hand on the wheel more than a couple minutes at a time with-out the feeling of pain in it. It seems ro start falling asleep then also.
Could be poor blood circulation to whatever is falling asleep. If it happens when you are asleep it may be because you're laying on it. Try to move your leg, arms or whatever falls alseep every so often if problem persists contact your doctor.