Physical
Sleep science
A full read
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?
Sources
- NCBI / StatPearls — Physiology, Sleep Stages (https://www.ncbi.nlm.nih.gov/books/NBK526132/)
- NIH Curriculum Supplement Series — Information about Sleep (https://www.ncbi.nlm.nih.gov/books/NBK20359/)
- Sleep Foundation — NREM Sleep (https://www.sleepfoundation.org/stages-of-sleep/nrem-sleep)
- PMC — Circadian Rhythms in Sleep and Recovery (https://pmc.ncbi.nlm.nih.gov/articles/PMC11221196/)
- CDC — Sleep duration recommendations for adults (7–9 hours)
- American Academy of Sleep Medicine (AASM) — clinical sleep guidelines