This Is Why You Can’t Keep Your Eyes Open When You’re Tired
Your eyelids feel heavy for a reason
Surely you’ve experienced the phenomenon of feeling like you can’t possibly keep your eyes open for one second longer when you’re tired — in the predawn hours feeding a newborn or while attempting to stay up and watch your favorite show. Why does this eyelid heaviness happen?
There are a multitude of reasons. Eyelids are made of muscles, and these muscles are at work all day, keeping the eyelids open and blinking. Like all muscles, says Dr. Kelsey Kleinsasser, an eye specialist based in Lee’s Summit, Missouri, they need rest. “During waking hours [our eyelids] are continuously blinking,” Kleinsasser says. “It’s analogous to being on your feet all day.” (One thing to note: Heavy eyelids are different than droopy or sagging eyelids, which can be caused by inflammation — think allergies — or ptosis, a condition where the upper eyelid droops due to muscle weakness that occurs with age.)
“During waking hours [our eyelids] are continuously blinking. It’s analogous to being on your feet all day.”
Aside from fatigue, dry eye is another cause of eyelid heaviness, says Kleinsasser. When eyes are open for an extended time (in other words, all day…
