This factor heavily depends on the amount of body fat, water, etc. in the body. Once the body runs out of other things to "scavenge" all that's left is muscles. Then you start to shut down. Starvation can occur in some people sooner or later than others. It can last for weeks, or only about a singular week. The average is ten (10) days.
REM sleep's function are that it helps in forming new memories, stimulates the central nervous system, and restores brain chemistry to a normal balance
