why are we never aware of the exact moment we fall asleep?

Question

why are we never aware of the exact moment we fall asleep?

In: Biology

Answer 1

I actually know the moment I fall into sleep most nights, because I have severe hypnic jerks (bodily twitches that occur literally as one falls asleep). My head will start twitching really hard against the pillow and it’s always the last thing I remember. It used to scare me until I discovered it was a harmless thing; now I kind of enjoy it because, in a very far-off half-conscious sort of way I’m like “yay I’m about to sleep.”