Eli5 why grown ups do not fall down from the bed?

Question

I am wondering why small kids ( even a few years old) fall down from the bed while changing their position but bigger children /adults do not, no matter how much they move while sleeping?

In: 2276

Answer 1

I have fallen out of a bed as an adult a few times. It was always either when I was in an unfamiliar place or had my sleep pattern disrupted.