Changes in daily stress reactivity and changes in physical health across 18 years of adulthood.

Background: Stress plays a pivotal role in physical health. Although many studies have linked stress reactivity (daily within-person associations between stress exposure and negative affect) to physical health outcomes, we know surprisingly little about how changes in stress reactivity are related to changes in physical health.

Purpose: The current study examines how change in stress reactivity over 18 years is related to changes in functional health and chronic health conditions.

Methods: Three measurement bursts from the National Study of Daily Experiences (N = 2880; 55% female) each included daily measures of stressor exposure and negative affect across 8 consecutive days, yielding 33 944 days of data across 18 years of adulthood. At each wave, participants reported their functional health limitations (ie, basic activities of daily living [ADL] and instrumental activities of daily living [IADL]) and chronic health conditions. Multilevel structural equation models simultaneously modeled stress reactivity at Level 1, longitudinal changes in stress reactivity at Level 2, and the association between changes in stress reactivity and changes in functional limitations and chronic conditions at Level 3.

Results: Higher levels of stress reactivity at baseline were associated with more functional health limitations 18 years later (ADLs: Est. = 0.90, P = .001; IADLs: Est. = 1.78, P < .001). Furthermore, individuals who increased more in their stress reactivity across the 18-year period also showed greater increases in their functional health limitations (ADLs: Est. = 4.02, P = .017; IADLs: Est. = 5.74, P < .001) and chronic conditions (Est. = 11.17, P = .008).

Conclusions: These findings highlight the strong connection between health and stress in daily life, and how they travel together across adulthood.