How can our bodies just know when we need to be up at a certain time?


Like if it’s a workday or something I’m always up on time, my brain even knows if it’s a work at home day or not and that seems to change how easy I get up. On weekends I’ll snooze late unless I have plans for something like a flight to catch when I’ll wake up when I want. But otherwise I’ll sleep, how does this work?

In: 5

I’m the same. Have never needed an alarm clock, unless, as you say, something extraordinary was happening. I always just say to myself what time I need to wake up, and I do.

Usually if your don’t wake up on time when you should, something negative will happen to the body, usually stress with she other things. The body obviously doesn’t want that, it’s not healthy, so you’ll wake up, so you don’t get stress. If that happens on a weekend you don’t get stress, because you have nowhere to be. So basically in your case the body adapts a 7 day system where the last two days are okay to sleep through

I’m going to say that most people can’t do that. I wake up because my alarm clock tells me to. Otherwise there wouldn’t be alarm clocks.

This exact specifics of this process aren’t well understood.

Humans have an internal clock called the Circadian Rhythm. The circadian clock is located in the hypothalamus part of the brain. This helps regulate not only how long you sleep but also what kinds of sleep you get. Light sleep vs Rapid Eye Movement (REM sleep) for example.

The Pineal gland secretes a hormone called melatonin which is responsible for helping you sleep. This gland works in concert with the hypothalamus to control your sleep cycle. It’s possible that your body learns to control and release an equal amount of these hormones during a normal nights sleep, that would mean that your internal alarm clock is chemically controlled and once the hormone wears off you wake up.

If you get into a regular rhythm of sleep + waking up your Circadian Rhythm gets used to it and adjusts your sleep pattern to get an expected amount of different kinds of sleep. Once you finish the last cycle of sleep it is able to wake you up roughly on time even without external stimuli (ie an alarm clock)

Exactly how it does this we don’t know, and it doesn’t work for everyone either.

Also you can easily override it. If you got to sleep consciously knowing you can sleep in tomorrow you can somehow disable your internal alarm clock and sleep through it. Possibly telling your pineal gland to release more melatonin that normal.