Sleep is a must which helps in repair of damaged nerve cells in the nervous system.., so first affected organ is brain ...,sleeping for at least 6-7hrs is must that too night sleep between11pm-4am is must .....,lack of night sleep may even cause infertility in males mostly ...so.better to avoid night awake.
Sleep deprivation is an interrogation technique. Sleep deprivation can break induce hallucinations & it can act like hypnosis/suggestibility. A real problem w/so many people working so many part time jobs is people driving nearly asleep which is as much an impairment as alcohol (drugs). Of course, RESTful sleep in the key; if people don't sleep regular hours, brain rest is compromised. Some people can function on less sleep than others, too. I myself function best w/interrupted sleep in 3 & 5 hour segments. & I'm more awake @ night than if I sleep 8 hours straight then get up @ 6 am for a day job.