1
$\begingroup$

Why is that whenever we feel sleepy, our eyelids start to feel heavier.

It is not like we can any time close our eyes and will immediately fall asleep. But, when we feel sleepy our eyelids automatically become heavy.

What causes heaviness of eyelids? Is it because of sleep hormone or something?

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.