Overview
- New MIT-reported findings show that after a sleepless night the brain briefly shifts cerebrospinal fluid in waking hours, a cleaning pattern tied to attention lapses and poorer task performance.
- Sleep scientists highlight severe risks from chronic short sleep, citing evidence of immune suppression after one 4‑hour night, higher cancer likelihood, and a 200% greater lifetime heart or stroke risk in adults over 45 who average under six hours.
- Large cohort data support an optimal adult duration around seven hours, with consistent 7–9 hours recommended and both under six and over nine linked to higher cardiometabolic and cognitive disease risk.
- Experts explain sleep’s architecture—circadian timing, adenosine sleep pressure, and NREM/REM cycles—with REM loss pronounced when reducing time in bed from eight to six hours.
- Guidance emphasizes QQRT hygiene (quantity, quality, regularity, timing), a cool dark room near 18°C, limiting evening caffeine, alcohol and screens, brief naps of about 20–30 minutes, avoiding compensatory naps in insomnia, and caution against device-driven ‘orthosomnia’ or dozing off in under five minutes as a sign of sleep debt.