Overview
- A MIT experiment found that after a sleepless night, cerebrospinal-fluid 'cleaning' pulses intrude during wakefulness, preceding attention lapses and memory slips.
- Experts reiterate that most adults need 7–9 hours, with habitual sub‑6‑hour nights tied to immune suppression, metabolic disruption and higher cardiovascular risk.
- Guidance centers on QQRT sleep hygiene, urging consistent schedules and environments that keep bedrooms dark, cool and quiet while respecting chronotype.
- Evidence updates exercise advice: strength training, yoga and tai chi improve sleep quality, but very intense sessions should finish at least 3 hours before bedtime.
- Clinicians caution that long or routine naps can worsen nighttime insomnia and cause grogginess, and that instant sleep onset or obsessive tracking may signal problematic sleep debt and orthosomnia.