ability to react to stimuli, but is more easily reversed than the state of being comatose. "How Much Sleep Do You Really Need?
Sleep and Mood (0:49. Studies just have shown that even partial sleep deprivation has a significant effect on mood. The panelists participated in a rigorous scientific process that included reviewing over 300 current scientific publications and voting on how much sleep is appropriate throughout the lifespan. Once you sleep well, your mood often returns to normal.