What does it mean when my arms constantly fall asleep when I'm asleep?

Every night I am woken up by my arms falling asleep throughout the whole night and it only happens at night when I'm laying down. I am 26 years old, no high blood pressure or history of heart or circulatory disease, however, I have had 4 kids, I'm about 60lbs overweight and occasionally smoke (about 4 cigaretts per week). I do have degenerative disc disease, herniated discs, and scoliosis though. Not sure if that helps, any ideas.