Background: Previous research has demonstrated that chronic stress negatively impacts cognition and overall health. Perseverative cognitions such as worry can hold the physiological response of a stressor in the body (Brosschot, Gerin, & Thayer, 2006). The current study consists of two components: 1) a conceptual replication examining whether worry mediates the effect of stress on somatic health and stress and 2) extension of the model with cognition as the outcome. Methods: This study used data from the second wave of the Midlife in the United States data collection: Project 1 (cross-sectional), Project 2 (daily diary), and Project 3 (cognition). Doing so approximated the time-series requirement of a mediation model and enabled access to the variables of interest. Mediation models were run via PROCESS software with covariates adjusted for at each path. Results: Controlling for age, gender, education, household income, and chronic health conditions, the mediation models revealed mediation of the effect of stress severity on somatic health by worry frequency, duration, and self-identification. Conclusions: Worry may be the process through which the physiological response to stress is prolonged thereby increasing the prevalence of effects on somatic health and cognition. By understanding the nuances of how stress impacts somatic health and cognition, prevention and intervention strategies can be implemented to reduce potential long-term outcomes. / Graduate