In your eye there are different types of light sensing cells. But some of these cells do NOT help you see. Some cells evolved BEFORE sight. These are there to regulate your body clock, your circadian rhythm.

Basically we evolved to work within the daily cycle. Wake up with the sun, go to sleep with the night. Generally now we are all out of wack. Sensing light is older than sight! Indeed light is a powerful factor in how you feel, how you sleep and how much you eat.

First, we are not signalling to our light sensing cells that we are about to go to sleep. People mess with this by keeping lights on, staring at a phone before bed, etc. If you set up your habits so that you dim lights at night and limit phone usage , you will get better sleep, and feel more energized.

Second, we are not signalling to our light sensing cells that it is time to wake up. The sun is the major trigger that you are missing. Indoor lights simply do not get to the same brightness. But, if you set your habits so that you go outside as soon as you wake up and see the sun , you will wake up better, get better sleep, and generally be more in sync.

These two videos explain it in detail very well.

For editors:

I created this not because I know much about it, but because I find it interesting, please help me elaborate on this topic!!!