Abstract
Mounting evidence indicates that regular engagement in aerobic exercise improves executive functioning and cerebrovascular health in older adulthood. Recent evidence also points toward some similar benefits in young adults, despite presumed ‘optimal’ brain health in that population. The present study sought to clarify which specific cognitive functions are linked to regular exercise in young adults (18-30 years), and to gain insight into the possible mechanisms underlying such links. To this end, the current study examined performance on a wide variety of executive function tasks in relation to aerobic fitness, self-reported habitual physical activity, and cerebrovascular health (as measured by resting cerebral blood flow, which was indexed by blood flow velocity through the middle cerebral artery; and cerebrovascular reactivity to carbon dioxide – the most potent regulatory stimulus of the cerebrovasculature). Multiple regression analyses revealed that more frequent physical activity, but not higher levels of aerobic fitness, predicted better cerebrovascular reactivity and superior inhibitory control over prepotent responses. Cerebrovascular reactivity also predicted better inhibitory control over prepotent responses. However, there were no observed links between exercise frequency, aerobic fitness, or cerebrovascular health and other executive processes such as selective attention, task switching, and working memory span. Finally, mediation analyses indicated that cerebrovascular reactivity could be an important mechanism through which regular exercise brings about improvements in inhibitory control over prepotent responses. Taken together, these results provide novel insight into the cognitive and cerebrovascular benefits that may be gained with regular exercise in an already high-functioning population.