Table 2.
Associations between caffeine consumption (total and by timing) and subsequent sleep.
| Sleep Index | Caffeine Consumption | |||
|---|---|---|---|---|
| Total | Evening | Afternoon | Morning | |
| TST | −.17 (−.31, −.02)* | −.47 (−.73, −.21)*** | −.24 (−.47, −.01)* | .05 (−.32, .41) |
| SOL | .13 (.06, .21)*** | .28 (.15, .41)**** | .21 (.09, .33)*** | .17 (−.02, .36)+ |
| SE | −1.59 (−2.51, −.67)*** | −3.75 (−5.36, −2.14)**** | −1.37 (−2.81, .06)+ | −.68 (−2.90, 1.53) |
| WASO | .01 (−.04, .07) | .04 (−.06, .14) | −.05 (−.14, .03) | .01 (−.12, .14) |
| REM sleep | −.12 (−.19, −.05)*** | −.19 (−.32, −.07)** | −.20 (−.31, −.09)*** | −.04 (−.22, .13) |
| Deep sleep | −.02 (−.06, .02) | −.01 (−.08, .06) | −.02 (−.09, .04) | −.03 (−.13, .07) |
| Light sleep | −.03 (−.12, .07) | −.27 (−.45, −.10)** | −.02 (−.17, .13) | .11 (−.13, .35) |
Each value shows the β (95% confidence intervals) associated with the caffeine predictor and sleep outcome from each linear mixed model. Each model covaried for age and sex. Statistical significance is indicated as follows: ****P < .0001, ***P < .001, **P < .01, *P < .05, +P < .10. REM = rapid eye movement, SE = sleep efficiency, SOL = sleep-onset latency, TST= total sleep time, WASO = wake after sleep onset.