system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do we wake up?

If we're sleeping and hear a loud noise or someone nudges us we tend to wake up from our sleep. But if no one bothers us what makes our bodies wake us up?
gpt
Your brain wakes you up. It has an internal clock which regulates the body, and it can prepare your body to wake up and eventually bring you back into consciousness. If you establish a regular sleeping schedule, your internal clock will adapt to it, often waking you up just before your alarm.