Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
Sleep progresses through cycles of roughly 90 minutes, each containing light sleep, deep (slow-wave) sleep and REM (rapid eye movement) sleep. Waking mid-cycle — especially during deep sleep — causes grogginess (sleep inertia). Timing your alarm to the end of a complete cycle (after 7.5 hours = 5 cycles, or 9 hours = 6 cycles) means you surface naturally during lighter sleep stages. Athletes prioritising recovery aim for at least 8–9 hours (5–6 full cycles).
- Cycles last roughly 90 minutes
- Stages: light, deep and REM
- Wake at cycle end to avoid grogginess
- 5 cycles (7.5 hrs) suits most adults
In practice
A full sleep cycle (progressing through light sleep, deep sleep and REM sleep) takes roughly 90 minutes to complete, and most adults need 4-6 full cycles per night for adequate restorative sleep — athletes in particular depend on sufficient deep sleep for growth hormone release and tissue repair, which is part of why elite sports programmes increasingly track sleep quality and duration as seriously as training load itself.
FAQ
How long does one sleep cycle typically last?
Approximately 90 minutes, progressing through light sleep, deep sleep and REM sleep stages, with most adults completing 4-6 full cycles across a typical night's sleep.
Why is deep sleep particularly important for athletes?
Deep sleep is when the body releases the most growth hormone and carries out significant tissue repair, making it especially important for recovery from training stress and physical adaptation.