Implications of Cumulative Life Event Stress for Daily Stress Exposure and Cardiovascular Reactivity Among Black and White Americans.

Objectives: Daily stress and cardiovascular reactivity may be important mechanisms linking cumulative life event stress with cardiovascular health and may help to explain racial health disparities. However, studies have yet to examine links between exposure to life event stress, daily stress exposure, and cardiovascular reactivity. This study assessed links between trajectories of life event stress exposure, daily stressors, and cardiovascular reactivity among Black and White individuals.

Methods: Participants are from the Stress and Well-being in Everyday Life Study in which 238 individuals (109 Black 129 White; ages 33-93), drawn from the longitudinal Social Relations Study, reported life event stress in 1992, 2005, 2015, and 2018. Of those individuals, 169 completed an ecological momentary assessment study in which they reported stress exposure every 3 hr, and 164 wore a heart rate monitor for up to 5 days.

Results: Latent class growth curve models revealed 2 longitudinal trajectories of life event stress: moderate-increasing and low-decreasing. Individuals in the moderate-increasing stress trajectory reported greater daily stress exposure and links did not vary by race. Black individuals in the low-decreasing trajectory and White individuals in the moderate-increasing trajectory showed positive associations between daily stress and heart rate (i.e., were reactive to daily stress exposure). The link between daily stress and heart rate was not significant among Black individuals in the moderate-increasing trajectory and White individuals in the low-decreasing trajectory.

Discussion: Individuals who experience more life events across the adult life course report greater daily stress exposure which has important implications for daily cardiovascular health. Black individuals with moderate-increasing life event stress show evidence of blunted daily stress reactivity (nonsignificant association between daily stress and heart rate) whereas Black individuals with low-decreasing life event stress show evidence of stress reactivity (positive association between daily stress and heart rate). White individuals showed the opposite pattern (albeit marginally). These findings expand the weathering hypothesis and indicate that chronic life event stress may be associated with blunted stress reactivity among Black individuals.