Sleep is necessary for humans to stay alive. Sleep is thought to be a higher form of regulation, covering a range of molecular and cellular processes to provide optimal wakefulness. At least one of the functions of sleep is to provide recovery. Sleep facilitates recovery of fatigue acquired during daily exercise – it is also a major modulator of hormonal levels, cellular repair, and immune health. Sleep maintains physiological homeostasis in general and is necessary for the clearance of metabolites...