CARDIOVASCULAR FITNESS AS A MODERATOR OF NEGATIVE AFFECT AND BRAIN CONNECTIVITY ACROSS THE ADULT LIFESPAN

Abstract

Two immense public health challenges today are mental health and aging – and these issues also overlap. Mental health is important to address in older adults because this population is unlikely to seek formal mental health services, and mental health issues can worsen other health problems during aging. Research consistently supports that exercise improves mental health and brain function in older adults, but there is scarce research on brain mechanisms by which exercise could improve mental health in older adults. We addressed this knowledge gap with 3 studies. In study 1, we assessed differences in older adults’ emotional processing during picture viewing after acute exercise versus a session of seated rest. In study 2, we compared resting-state functional connectivity (rsFC) outcomes in major cognition and affect-related networks in older adults (within- and between-network connectivity and network segregation) after acute exercise versus rest. In study 3, we tested associations between cardiorespiratory fitness, negative affect, and large-scale network FC (within-network connectivity, between-network connectivity, between-network segregation) of networks spanning the entire brain across the healthy adult lifespan (ages 36-100). We had affective data in studies 1 and 3. After exercise relative to rest in study 1, we found increased positive affect and various regional changes in pleasant and unpleasant emotional activation that may support better mood. After exercise relative to rest in study 2, we found increased network segregation via decreased between-network connectivity between internal and external state-focused networks, suggesting another mechanism of post-exercise mood improvement. Finally, in study 3, we found that fitness had a negative relationship with poor affective disposition (negative affect and anger hostility), as well as various rsFC associations that did not mediate that negative relationship; greater cardiorespiratory fitness and greater anger hostility were each related to greater connectivity within and between multiple networks, and the interaction of fitness and poor affective disposition (negative affect or anger hostility) was associated with greater rsFC within and between multiple networks and lower segregation of a few networks. These studies’ results suggest that benefits of exercise for mental health in older adults may involve multiple mechanisms of different scales and encourage further research.