Day-to-day relations between stress and sleep and the mediating role of perseverative cognition

The goals of this longitudinal diary-based study were to shed light on the day-level relationship between stress and subsequent sleep, and to examine whether perseverative cognition is a mediating factor in this relation.

A total of 44 Dutch PhD students were followed during a two-month period, from one month before their public thesis defense (ie, a stressful life event), until one month thereafter. Participants completed short evening and morning questionnaires on eight occasions (in anticipation of and following the defense), including questions about day-level stress, sleep quality, and perseverative cognition. Objective sleep parameters were collected with the SenseWear Pro Armband.

Multilevel analysis was used to analyze daily observations nested within individuals. Analyses revealed that day-level stress was not directly related to subsequent subjective sleep indicators or to subsequent objective sleep indicators. Day-level stress was significantly associated with day-level perseverative cognition, and daily variations in perseverative cognition were significantly related to several day-level objective sleep parameters (sleep efficiency, marginally to number of awakenings, and wake after sleep onset), and to several day-level subjective sleep parameters (sleep quality, number of awakenings, wake after sleep onset). Finally, mediation analyses using path analysis suggested that, on the day level, perseverative cognition functions as a mediator between stress and several sleep parameters, namely, subjective sleep quality, objective sleep efficiency, and subjective wake after sleep onset.

Perseverative cognition is a promising explanatory mechanism linking day-level stress to subjective and objective measures of sleep.