The biological clock of our body determines who sleeps.
A special part of the brain has a clock that tells when it is day and when it is night.
The biological clock tells the body when it is day and when it is night.
Those whose sleeping pattern is like that, will get sleep only at that time.
Doctors believe that 8 hours of sleep a day is ideal.
But many people can't sleep for 8 hours uninterrupted due to various demands of daily life.
Some people do not sleep despite being tired.
Some people fall asleep even after 8 hours of sleep.
The share of sleep in their whole day is very high.
The amount of daily sleep increases in any disease.