PROJECT SUMMARY/ABSTRACT Regular exercise and lifestyle physical activity (PA) are critical for quality of life and longevity among a growing aging population. Aging produces changes to the structure and function of the heart, which increases vulnerability to cardiovascular disease (e.g., coronary heart disease, heart failure, and stroke), frailty and falls, dementia, and Alzheimer disease. Exercise helps to slow the progression of aging-associated changes to the heart by promoting adaptations to the cardiovascular and pulmonary system, however exercise initiation and maintenance can be difficult in aging adults due to deconditioning, pain, frailty, and disability. Exercise anxiety is a novel mechanism related to non-adherence to exercise and lifestyle PA, that is characterized by cognitive, behavioral, and physiological underpinnings. Exercise anxiety is particularly elevated in individuals with cardiovascular disease given that the physical sensations of exercise often feel similar to the sensations experienced or attributed to cardiovascular disease (e.g., shortness of breath, chest tightness, dizziness, fatigue, pain). We developed a mechanistically-informed cognitive-behavioral intervention to target exercise anxiety, called Behavioral Exposure For Interoceptive Tolerance (BE-FIT). In our Stage I pilot study, we developed and demonstrated initial support for BE-FIT in low active patients with elevated exercise anxiety enrolled in outpatient cardiac rehabilitation. The intervention was six sessions delivered as an adjunctive treatment during the initial weeks of cardiac rehabilitation, and involved behavioral exposure to feared bodily sensations and exercise situations, elimination of false safety behaviors and avoidance, and use of a wrist- worn activity monitor for PA feedback and activity goal-setting. Our preliminary work established the feasibility, acceptability and safety of BE-FIT. We also found evidence of target engagement (large-sized reductions in exercise anxiety) and initial evidence for the effect of BE-FIT on exercise outcomes, including significant increases in steps/day and moderate-vigorous PA minutes/day at the end of treatment. Given these very promising data, we propose to take the next step by conducting a fully-powered Stage II randomized controlled trial (RCT) to test the efficacy of BE-FIT, compared to a Health Education Control (HEC) intervention, for adults (N=146) who are ≥40 years of age, cleared for outpatient CR, low active and have elevated exercise anxiety, and to test whether changes in exercise anxiety are associated with subsequent changes in exercise outcomes at EOT and follows-ups (Week 12, 18, and 24). We will evaluate intervention effects on exercise anxiety and its components, including cognitive processes (catastrophizing, uncertainty, discomfort intolerance), behavior (avoidance/safety behaviors), and physiological function (cardiac vagal control). This project will contribute scientific and clinical understanding of anxiety and PA. If the efficacy of the BE-FIT can be established, this intervention could serve as an adjunctive treatment to cardiac rehabilitation and be adapted for other patient populations and treatment settings, for PA promotion in support of successful aging.

PROJECT NARRATIVE Regular exercise and lifestyle physical activity (PA) is critical for quality of life and longevity, and particularly important for a healthy heart. We aim to test the efficacy of a new cognitive-behavioral intervention, called BE- FIT, for patients enrolled in outpatient cardiac rehabilitation that reduces exercise anxiety, a common barrier to physical activity.