eli5 : can somebody explain circadian rhythms?
In: 6
Your brain has a “clock,” and part of it is the suprachiasmatic nucleus. As it tracks what “time” it thinks it is, your brain will change different hormones and stuff in your body. For example, when it’s getting time to sleep, your brain releases chemicals that make you feel sleepier.
But it’s a lot more than just sleep. Examples of other stuff that follows your internal clock: pain tolerance, rate of digestion of food, your body temperature.
It is a rhythm because it goes up and down depending on the time your body thinks it is (more sleepy at night, less sleepy in day). But it’s not literally based on Earth time. When you fly really far, the actual time might be 1pm but your body still thinks it’s 3am like back home. Your body adjusts to earth day time based on light and darkness your eyes receive.
Last bit: the average natural circadian clock in humans is a bit longer than the actual day. So if you lived in a box without sunlight and no clock, you’d gradually lose track of your normal sleep time. However, individuals also vary: some have faster or slower natural clocks. It’s the sunlight and darkness that helps us maintain a good cycle tuned to our environment. Artificial light may interfere with this.
Your body has an automatic sleep timer. It knows when you should be sleeping and when you should be awake, based on when you see the sun come up and go down.
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