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

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 F-fluorodeoxyglucose positron emission tomography/computed tomographic imaging. Stress-related neural activity was measured as the ratio of resting amygdalar-to-cortical activity (AmygA). 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 AmygA (standardized β: -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. AmygA 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.