Why do people often wake up just before the alarm?

Scientists believe that a person wakes at the same time every day because of the body’s internal “body clock” . It controls and co-ordinates the cyclic processes of the body over a twenty-four-hour period The body clock cycle or rhythms are important in determining the sleep patterns of people.

Waking before the clock rings is also thought to be part of our sub-conscious mind. It is assumed that the subconscious mind awakes the mind and the body.