Key Takeaway
Caffeine consumed even 6 hours before bed significantly disrupted sleep, reducing total sleep time by over 1 hour and supporting delayed morning caffeine timing.
Summary
This double-blind study examined how caffeine timing affects sleep quality.
Results showed that 400mg caffeine (about 2 cups of coffee) disrupted sleep even when consumed 6 hours before bed, providing scientific basis for limiting caffeine to morning hours.
Methods
- Double-blind placebo-controlled
- 12 healthy adults
- Caffeine at 0, 3, or 6 hours before bed
- Sleep monitor measurements
Key Results
- 6-hour caffeine reduced sleep 1+ hour
- Disrupted sleep architecture
- Individual sensitivity varies
- Morning caffeine safest
Limitations
- Small sample size
- Single dose tested
- Young healthy adults only