Don’t Be Held Hostage by “8-Hour Sleep”!
Many people know that “insufficient sleep” can lead to sudden death, cardiovascular diseases, cancer, etc., but most are unaware that “excessive sleep” also increases mortality risk. The “8-hour sleep theory” is widely known, yet some who force themselves to sleep 8 hours nightly wake up even more tired. Increasing studies show this may be a misconception—optimal sleep duration isn’t necessarily 8 hours.
Optimal Sleep Duration Revealed: Not 8 Hours
Past sleep-health studies mostly focused on Western populations. A 2021 study in JAMA (involving over 320,000 Asians from Japan, China, Singapore, and South Korea) found 7 hours of nightly sleep is “optimal” for Asians. The link between sleep duration and all-cause mortality follows a “J-curve”: 7 hours minimizes risks of all-cause mortality, cardiovascular disease, and other deaths for both genders. Sleeping 8+ hours raises mortality risk—for men, 8/9/10 hours increases all-cause mortality by 9%/18%/43% vs. 7 hours; less than 5 hours raises it by 16%. For women, even 1 hour more or less than 7 hours boosts all-cause mortality.
Sleep Quality Matters More Than “8 Hours”
Dr. An Jianxiong (Air Force General Hospital) notes 8 hours is an average, not universal. The real test is next-day alertness: if you wake up refreshed despite shorter sleep, your body’s needs are met. Good sleep quality means: falling asleep within 30 minutes (20 for under-6s), waking ≤3 times nightly (falling back asleep within 20 minutes), and feeling energetic. Sleep has 4-6 cycles (90 mins each): light sleep (easy to wake), deep sleep (tissue repair, immunity boost), and REM sleep (dreaming, memory consolidation). Completing these cycles ensures restful sleep.
5 Tips to Improve Sleep Quality
- Stick to a routine: Adults sleep 10 PM-11 PM, wake 6 AM-7 AM; seniors sleep 10 PM-11 PM, wake 5 AM-6 AM. Avoid weekend “revenge staying up late.”
- Create a cozy environment: Keep it quiet, comfortable, warm, and dark (use blackout curtains/earplugs).
- Control diet before bed: Finish dinner 3-4 hours pre-sleep; drink moderately 1-2 hours pre-sleep to avoid nighttime bathroom trips.
- Relax pre-sleep: Try sleep yoga or meditation to unwind.
- Do sleep-friendly exercises: Yoga (extends sleep by 110 mins on average), tai chi, walking, or jogging improve sleep efficiency.
In short, 8 hours isn’t critical—“sound sleep” determines next-day energy.