Why cant rest be simply as ok as sleep..?

What makes us sleep even if we dont do anything but lay around adjectives day? what activities do sleeping do that resting doesn't?Why cant rest be simply as ok as sleep..?
Resting does not allow your body to go into the REM stage of sleep, which is the repairitive stage. It help metabolism and cellular function. Lack of adequate sleep can bring excessive build ups of lactic acid surrounded by your muscles and enzymes, causing fatigue, muscle and amalgamated pain. Lack of sleep can also raison d`¨otre mental fatigue, lowered metabolism, depression, lowered bone density, immune supression,etc. There have be strong links between sleep deprivation and fibromyalgia as well as CFT.
One possible plea might be . . . studies show that if you don't get that "R. E. M." (rapid eye movement) sleep that you don't get up up feeling as rejuvenated.
sleep is a time for the mind to rest, although you are not doing anything while laying around, your mind is still somewhere else. while you sleep your mind get to rest, you dont think in the order of anything, its perfect.
When we sleep, weighty sleep, that is when our body "recharges" itself. Our sleep time is when our bodies treat, grow, and rejuvenate. This includes our minds. It is a well prearranged fact that sleep deprivation can formulate a person nutty. Even when we simply sit around all light of day long, our bodies (and minds) still require this "recharging" time.
When we simply rest, we are not getting our required deep sleep, otherwise certain as R.E.M. sleep. If we are missing our REM sleep we will eventually not be able to function properly, and it can organize to physical illness.