Effect of Stress-Related Neural Pathways on the Cardiovascular Benefit of Physical Activity.

ABSTRACT

BACKGROUND: The mechanisms underlying the psychological and cardiovascular disease (CVD) benefits of physical activity (PA) are not fully understood. OBJECTIVES: This study tested whether PA 1) attenuates stress-related neural activity, which is known to potentiate CVD and for its role in anxiety/depression; 2) decreases CVD in part through this neural effect; and 3) has a greater impact on CVD risk among individuals with depression. METHODS: Participants from the Mass General Brigham Biobank who completed a PA survey were studied. A subset underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomographic imaging. Stress-related neural activity was measured as the ratio of resting amygdalar-to-cortical activity (AmygAC). CVD events were ascertained from electronic health records. RESULTS: A total of 50,359 adults were included (median age 60 years [Q1-Q3 45-70 years]; 40.1% male). Greater PA was associated with both lower AmygAC (standardized ß -0.245; 95% CI -0.444 to -0.046; P = 0.016) and CVD events (HR 0.802; 95% CI 0.719-0.896; P < 0.001) in multivariable models. AmygAC reductions partially mediated PA's CVD benefit (OR 0.96; 95% CI 0.92-0.99; P < 0.05). Moreover, PA's benefit on incident CVD events was greater among those with (vs without) preexisting depression (HR 0.860; 95% CI 0.810-0.915; vs HR 0.929; 95% CI 0.910-0.949; P interaction = 0.011). Additionally, PA above guideline recommendations further reduced CVD events, but only among those with preexisting depression (P interaction = 0.023). CONCLUSIONS: PA appears to reduce CVD risk in part by acting through the brain's stress-related activity; this may explain the novel observation that PA reduces CVD risk to a greater extent among individuals with depression.