Too much sleep: when long nights are a warning sign
October 6, 2026 · 13 min read
Walker and Attia both address oversleeping, noting that very long sleep is often a marker of poor sleep quality, illness or depression. It corrects the idea that more time in bed is always better.
The rules, numbers and steps worth keeping in front of you.
- Mortality is higher at short sleep and rises again at very long sleep.
- Walker places the upturn past about 10 to 11 hours.
- Leading explanation for both experts: sick people sleep more.
- Walker: broken sleep makes people stay in bed longer to compensate.
- Healthy sleep efficiency is about 85 percent or more of time in bed asleep.
- In depression, long time in bed was mistaken for long sleep; actual sleep is usually short and broken.
- Sleep timing out of line with the body clock predicts depression.
- Attia and Walker both leave open that too much sleep could itself be harmful.
- Huberman: most people need at least six and ideally seven to eight hours; the young need more.
- Huberman: repeatedly falling asleep in the day means something is off.
- Catch-up sleep after real deprivation is repayment, not oversleeping.
- Walker: after a bad night do nothing; no lie-in, no nap, no early bedtime.
- Attia: keep naps near 20 minutes if you already sleep enough.
- See a doctor for new or persistent long sleep, low mood or daytime exhaustion.
This is the short form. The full insight has every expert's reasoning, their own words and the sources.