Table 2.
Multilevel models of daily associations between sleep and stress.
| Predictor | Outcome | Fixed effect | Model comparison test | |
|---|---|---|---|---|
| b (SE) | LRT (df = 2) | |||
| Sleep reactivity (to stress) | Stress(1–5 scale) | Diary TST(min) | −9.44 (2.07)*** | 18.32, p < .001 |
| Stress | Acti TST (min) | −3.97 (1.87)* | 2.52, p = .2 | |
| Stress | Diary sleep efficiency(%) | −0.57 (0.18)*** | 19.44, p < .001 | |
| Stress | Acti sleep efficiency (%) | −0.07 (0.13) | 0.001, p = 1.0 | |
| Stress reactivity (to sleep) | Diary TST(min) | Stress(1–5 scale) | −0.001 (0.0001)*** | 25.63, p < .001 |
| Acti TST(min) | Stress | −0.001 (0.0001)*** | 13.43, p = .001 | |
| Diary sleep efficiency(%) | Stress | −0.004 (0.0016)* | 7.31, p = .03 | |
| Acti sleep efficiency (%) | Stress | −0.002 (0.0018) | 0.07, p = .96 |
Bolded reactivity indices indicate that the random slope significantly improved the model fit (i.e. the variability of the reactivity across individuals), based on the model comparison test. The significance of the fixed slopes: *p < . 05, ***p<.001.
acti, actigraphy; diary, sleep diary; LRT, Log-likelihood ratio test.