system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How do our bodies "Naturally" wake up with no alarm, nobody mowing their lawn outside etc?
gpt
Your body has what's called Circadian Rhythm. It determines basically when you sleep and when you eat but is affected by the sun and your environment and any number of other factors. Even more basically it tells your body's metabolism when to work and when to chill out. If you've been sleeping too long your body will wake you up because you need energy whether that's simply the sun or water or food. Conversely too much of either of those things are likely to put you to sleep so your body has time to recoup.