sleeping hours; hours of sleep
Refers to the amount of time one sleeps, often in the context of health or daily routine.
It is important to ensure sufficient sleeping hours.
My sleeping hours yesterday were only four hours.
It's important to make sure children get enough hours of sleep.
Lately I'm tired because I'm not getting enough sleep.
Before the exam, I cut into my sleep hours to study.
I try to get seven hours of sleep every day.