Sleep Duration
Quality is non-negotiable, but quantity is the foundation of biological recovery.
The “8-hour rule” is a generalization. While it’s a good baseline, sleep duration needs change drastically throughout your life and depend on your lifestyle, genetics, and daily physical exertion.
| Age Group | Recommended Hours |
|---|---|
| Newborns (0-3 months) | 14 – 17 hours |
| School Age (6-13 years) | 9 – 11 hours |
| Teens (14-17 years) | 8 – 10 hours |
| Adults (18-64 years) | 7 – 9 hours |
| Seniors (65+) | 7 – 8 hours |
The 90-Minute Math
Most humans complete 5 to 6 sleep cycles per night. Since each cycle lasts approximately 90 minutes, your ideal duration should ideally align with these windows:
- 7.5 Hours: 5 complete cycles (Ideal for most adults).
- 9.0 Hours: 6 complete cycles (Ideal for athletes or during recovery).
Signs You Are Not Sleeping Enough
If you experience any of these, you are likely accumulating Sleep Debt:
- Reliance on caffeine to function before noon.
- Feeling sleepy while driving or in quiet meetings.
- Irritability and low stress tolerance.
- The “Weekend Catch-up”: Sleeping significantly more on Saturdays/Sundays.
Are you owing hours to your body?
Calculate your accumulated deficit and learn how to pay it back safely.
Use Sleep Debt Calculator →