What is the Reason for Getting Sleep?

Every human being gets sleep.  So what is the reason behind this?   Sleep helps to be strong both physically and mentally.  Heart beat and breathes get slow down while body is in sleep.   So body gets relaxation and regains energy while it is in sleeping condition.  While the body is awake it loses energy because of the day-to-day activities.  So body regains the energy while in sleep.  At the same time, during sleep the brain works actively, keeps the experiences safely in the mind and erases the unnecessary thoughts.    The biological clock in the body determines the rest time, it controls the neurons and results a sound sleep.  Pineal glands releases melatonin hormone which results in a sound sleep during the nights.

Duration of the sleep is genetically dependent and varies between the persons.  Six to eight hour of sleep is a healthy habit.