Why Does The Urge To Sleep Take Place At Night?

Season's Greetings!
You know, I wondered my self why this happens. A normal human is usually energetic and fully awake in the day, but at night, his eyes dim up and then its like the moon and the stars cast a spell that puts him fast asleep. Why? I asked my self...why not the other way round? Why isn't it like, we sleep hard in the morning and at night, we are fully awake? Well, I found out, just like how you are about to.
Melatonin.
This chemical is produced in the brain and it makes you feel sleepy. Well, It doesn't explain why we are bound to sleep at nights, does it?
The phenomenon is similar to that of the retina. The brain is sensitive to sunlight. You wake up in the morning because your brain tells you its time to wake up because the sun is up and melatonin has probably been exhausted. But as night approaches, your brain makes a chemical(melatonin) which makes you feel very sleepy.

If you are a good observer, you would notice that you sleep easily when you turn off the lights at night but you might be a little bit active and reluctant to sleep when the light is on, well for normal cases. Well this is because your brain is still sensitive to the lights and as soon and you turn off the lights and everywhere goes dark, melatonin is activated.

Furthermore, it is very possible you find it reluctant to sleep when your eyes are fixed on a TV screen or laptop screen, which means even the light form  a bright screen, maybe computer, maybe something else,
Furthermore, it is very possible you find it reluctant to sleep when your eyes are fixed on a TV screen or laptop screen, which means even the light form  a bright screen, maybe computer, maybe something else, can keep you awake.

Wait, but does that mean if we sleep all day, we would still feel sleepy at night?
If you wanna know...

Stay tuned.

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