How exactly does your body decide when to wake up? ?

Question

What makes the body determine when you've slept enough?

Answer 1

changes in bodily and environmental conditions

The circadian clock is an enzyme controlling system in your body, when it detects changes in light and temperature and you release enzymes which inhibit bodily processes

The Circadian Rhythm determines the ideal timing of a sleep episode, any constant condition makes the rhythm persist and makes you stay asleep, such as constant darkness or lack of noise. Changes in these conditions make you awake. Your body changes temperature throughout a sleep episode, it reaches its minimum about an hour before you wake, this change makes you wake up.

Melatonin is a hormone which controls your circadian rhythm by chemically causing tiredness, it is dependent on light, in daylight it is inhibited and when it is dark or in dim light your body produces it. so you produce it at night and while you sleep and when it gets lighter in the morning it gets inhibited and eventually you wake up

Answer 2

You have an internal biological clock which syncs to the natural daily day-night cycle. You wind down at night, yawning and eventually sleeping, and then before dawn, you wind up and eventually wake for the day. The cycle is about 24 hours long. Sleep studies have been done where people were in a room with no indication of time, no windows and so forth. They could determine their own daily schedule. The requirements were to eat 3 meals a "day" from the time they wake up for the day until they go to sleep at the end of their day. Most people had a internal clock which ran at about 23 hours for an unregulated length without clues to what time was passing or when daylight was.