Physical
Sleep science
10 sections · 10 pts/section
Section 1 / 10
Why we sleep
Sleep can look like nothing is happening. The eyes close. The body goes still. But inside, the night is busy.
sleep
A nightly rest state. The body repairs and the brain sorts. Active work, not just an off switch.
Your guess
If sleep were just idle time, skipping it should be easy. How long can a person stay fully awake before the body forces sleep?
At night, the body fixes what the day wore down. The brain sorts the day into memory. Neither job can happen while a person is awake.
Adults need about 7 to 9 hours. Getting less, every day, has a price. The price shows up in mood, memory, and health.
Sleep is downtime — wasted hours that could be spent doing more.Tap to reveal
No. This is hard to spot because nothing looks like it is happening. The body is still and quiet. But that stillness hides the work. Repair and memory-sorting run all night.