Age, Daily Stress Processes, and Allostatic Load: A Longitudinal Study.

Objective: The present study examined age differences in the association between daily stressors and allostatic load. Method: Participants consisted of 317 adults (34-84 years) who participated in Waves 1 (1996-1997) and 2 (between 2005 and 2009) of the Midlife Development in the United States Survey. During Wave 1, participants reported the stressors they encountered across eight consecutive days. Within-person affective reactivity slopes indexing change in negative affect from a nonstressor day to a stressor day were calculated for each participant. Affective reactivity and stressor exposure scores at Wave 1 were used to predict allostatic load at Wave 2. Results: Heightened levels of affective reactivity at Wave 1 predicted elevated levels of allostatic load at Wave 2 but only among older adults who also reported high levels of stressor exposure. No significant associations emerged for younger adults. Discussion: Daily stress processes may be one pathway through which age-related physical health declines occur.