Hypothesis 1: Ecologically assessed individual perceptions of psychosocial stress are inversely associated with the probability of subsequently engaging in accelerometer- and altimeter-assessed usual physical activity. Hypothesis 2: accelerometer- and altimeter-assessed usual physical activity is inversely associated with subsequent perceptions of psychosocial stress (acutely post-usual physical activity and end-of-day summary for the day). Exploratory Aims: We will explore: 1) if the sources of stress exposure accompanying the momentary stress perceptions that are predictive of usual physical activity are person-specific, or if they can be modeled normatively; 2) if those randomized to receiving information regarding their personalized stress fingerprint those person-specific stress sources associated with decreased usual physical activity both decrease their exposure to those stressors and increase their usual physical activity; and 3) if past life stressors (e.g., divorce, loss of employment, bankruptcy), resources (e. g., social support, financial), and vulnerabilities (e.g., early childhood adversity) are moderators of the bi-directional relationship between psychosocial stress perception and usual physical activity.