In 2013, studies proved for the first time that sleep is biologically fundamentally necessary for animals to clear away neurotoxic waste that builds up in the brain while awake. Research also shows that failing to adequately clear away these toxins plays a significant role in developing certain brain disorders. The system through which the cleanup takes place is called the glymphatic system and research has shown that it is 10 times more active while an animal is sleeping.
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The record holder for going the longest without sleep held out for almost 19 days.