Why people need sleep?
Human need 1/3 time of their life to sleep. The reason that people must sleep is that cerebra need to relax and maintain some most important neuron group in deep sleep. There are 10 billions nerve cells in human cerebra which transfer messages to all the body corners, unused nerve cell will atrophy and even die. The animals experiment also proved that white rat will die one after another if they don’t sleep for several weeks, but their apparatus haven’t been found any obvious damage, just because they lack sleep serious lead to the immune function break down, and can’t resist the bacterial affect, and then it die. Also, some study & testing show that a person whose sleep less 4 hours will catch a disease more easier than those whose sleep time reach 7-8 hours, even die. And if a person who don’t sleep in 72 hours continuingly will be in deranged mentally. According the EEG and other body’s change judged, a normal person when he sleep, first enter the NREMS, there are four stages: when