Within-person associations of optimistic and pessimistic expectations with momentary stress, affect, and ambulatory blood pressure

Background and Objectives: Although dispositional optimism and pessimism have been prospectively associated with health outcomes, little is known about how these associations manifest in everyday life. This study examined how short-term optimistic and pessimistic expectations were associated with psychological and physiological stress processes. Methods: A diverse sample of adults (N = 300) completed a 2-day/1-night ecological momentary assessment and ambulatory blood pressure (ABP) protocol at ∼45-minute intervals. Results: Moments that were more optimistic than typical for a person were followed by moments with lower likelihood of reporting a stressor, higher positive affect (PA), lower negative affect (NA), and less subjective stress (SS). Moments that were more pessimistic than typical were not associated with any affective stress outcome at the following moment. Neither optimism nor pessimism were associated with ABP, and did not moderate associations between reporting a stressor and outcomes. Discussion: These findings suggest that intraindividual fluctuations in optimistic and pessimistic expectations are associated with stressor appraisals.