Linking stable and dynamic features of positive affect to sleep.

BACKGROUND Poor sleep contributes to adult morbidity and mortality. PURPOSE The study examined the extent to which trait positive affect (PA) and PA reactivity, defined as the magnitude of change in daily PA in response to daily events, were linked to sleep outcomes. METHODS Analyses are based on data from 100 respondents selected from the National Survey of Midlife in the United States. RESULTS Multilevel analyses indicated that higher levels of trait PA were associated with greater morning rest and better overall sleep quality. In contrast, PA reactivity was associated with diminished sleep efficiency. Finally, interactions between PA reactivity and trait PA emerged on all three sleep measures, such that higher event-related change in daily positive affect was associated with impaired sleep, especially among individuals high in trait PA. CONCLUSIONS Results suggest that high trait PA, when coupled with high PA reactivity, may contribute to poor sleep.