Move your feet and sleep: A longitudinal dynamic analysis of self-reported exercise, sedentary behavior, and insomnia...

Insomnia symptoms are associated with poor physical and mental health. Exercise is associated with good sleep while sedentary behavior is associated with poor sleep. This study investigated the longitudinal, dynamic associations among exercise, sedentary behavior, and insomnia symptoms.

Seven hundred and fifty-six adults (M_age=47.2years, 54.9% female) took part in an online longitudinal study investigating sleep and health across the lifespan. Participants reported duration of moderate-to-strenuous exercise, percentage of day spent sitting, and insomnia symptoms (Insomnia Severity Index [ISI]). The ISI was scored as a total score and two-factor scores: (1) Sleep Disturbance (items 1, 2, 3) and (2) Daytime Dysfunction (items 4, 5, 6, 7). Multilevel modeling was used to examine the typical (i.e., between-persons) and individual (i.e., within-persons) associations among sedentary behavior, exercise, and insomnia symptoms.

Sedentary behavior was significantly associated with total ISI scores at both the between-person and within-person levels (β = 0.036, t = 3.23, p = .001; β = 0.014, t = 1.99, p = .048). Both between-persons and within-person levels of sedentary behavior were associated with Daytime Dysfunction (β = 0.028, t = 3.79, p < .001; β = 0.009, t = 2.08, p = .039). Exercise was associated with total ISI and Daytime Dysfunction scores at the between-persons level but not at the within-persons level (β = 0.028, t = 2.57, p = .01; β = -0.002, t = -3.02, p = .003).

Sedentary behavior was a more consistent and robust predictor of insomnia symptoms than exercise. The association between sedentary behavior and insomnia symptoms was dynamic in that when an individual reported being more sedentary than their norm, they also reported more insomnia symptoms. Future analyses should examine potential moderator variables and comorbid conditions.