Why does the area under your eyes get darker when you’re sleep deprived?

Question

I’ve always wondered this. What exactly causes eye bags and dark circles?

In: Biology

Answer 1

There’s a bunch of blood vessels that feed into your eyes. When you don’t get enough sleep those blood vessels get bigger which darkens the skin under your eyes. When you sleep they expand and contract to rinse and refresh your eyes. But if you are sleep deprived that process doesn’t happen or doesn’t finish.