internal timing system that helps regulate sleep and wakefulness.
If that rhythm shifts, you may find yourself becoming sleepy unusually early and waking earlier than expected.
For some people, consistently waking between 3 and 5 a.m. can even be associated with an advanced sleep-wake pattern.
Alcohol and Caffeine Can Also Affect Your Sleep
A drink in the evening may make you feel sleepy initially, but alcohol can disrupt sleep later in the night.
Caffeine consumed too late in the day can also make it harder to maintain uninterrupted sleep.
