The effect of caffeine on subsequent sleep: A systematic review and meta-analysis.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
caffeine consumption | decrease | total sleep time | - | 45 min | reduced | #1 |
caffeine consumption | decrease | sleep efficiency | - | 7% | reduced | #2 |
caffeine consumption | increase | sleep onset latency | - | 9 min | increase | #3 |
caffeine consumption | increase | wake after sleep onset | - | 12 min | increase | #4 |
caffeine intake | increase | duration of light sleep (N1) | - | +6.1 min | increased | #5 |
caffeine intake | increase | proportion of light sleep (N1) | - | +1.7% | increased | #6 |
caffeine intake | decrease | duration of deep sleep (N3 and N4) | - | -11.4 min | decreased | #7 |
caffeine intake | decrease | proportion of deep sleep (N3 and N4) | - | -1.4% | decreased | #8 |
The consumption of caffeine in response to insufficient sleep may impair the onset and maintenance of subsequent sleep. This systematic review and meta-analysis investigated the effect of caffeine on the characteristics of night-time sleep, with the intent to identify the time after which caffeine should not be consumed prior to bedtime. A systematic search of the literature was undertaken with 24 studies included in the analysis. Caffeine consumption reduced total sleep time by 45 min and sleep efficiency by 7%, with an increase in sleep onset latency of 9 min and wake after sleep onset of 12 min. Duration (+6.1 min) and proportion (+1.7%) of light sleep (N1) increased with caffeine intake and the duration (-11.4 min) and proportion (-1.4%) of deep sleep (N3 and N4) decreased with caffeine intake. To avoid reductions in total sleep time, coffee (107 mg per 250 mL) should be consumed at least 8.8 h prior to bedtime and a standard serve of pre-workout supplement (217.5 mg) should be consumed at least 13.2 h prior to bedtime. The results of the present study provide evidence-based guidance for the appropriate consumption of caffeine to mitigate the deleterious effects on sleep.