Waking Up at 3 or 4 AM Every Night? Your Body May Be Trying to Tell You Something Important

1. Natural Sleep Cycle Is Changing Throughout the Night

One of the simplest explanations for waking around 3 or 4 AM is the way human sleep naturally changes as the night progresses.

Sleep is not one continuous state. Instead, your brain moves through several stages, including light sleep, deep sleep, and REM sleep, the stage most strongly associated with vivid dreaming.

These stages repeat throughout the night.

During the earlier part of the night, deep sleep generally makes up a larger proportion of your sleep. As morning approaches, deep sleep becomes less common, while lighter sleep and REM periods become longer.