Caffeine Effects on sleep Taken 0, 3, or 6 Hours before Going to Bed

This study examined how caffeine consumption at different times before bed affects sleep in 12 healthy adults. Caffeine (400 mg) taken 0, 3, or 6 hours before bedtime significantly reduced total sleep time by over an hour and increased wakefulness, even at the 6-hour mark. These effects were observed objectively through sleep monitoring. Caffeine disrupted slow-wave sleep but had no significant impact on REM sleep. This research underscores the importance of avoiding caffeine late in the day to preserve sleep quality and cognitive recovery.

To optimize sleep quality, avoid caffeine intake at least 6 hours before bedtime. Reducing afternoon and evening caffeine consumption helps maintain sleep duration and restorative phases like slow-wave sleep. While this controlled study provides strong evidence for caffeine's disruptive effects, individual sensitivity may vary. Adopting these habits can support better sleep hygiene and cognitive performance.