Abstract
An extensive literature reports that a single bout of exercise provides a post-exercise executive function (EF) benefit. The majority of this work has focused on identifying the exercise type (e.g., aerobic vs. resistance) and/or duration that optimizes an EF benefit; however, limited work has examined whether the distribution of work-to-rest (i.e., density) impacts the EF benefit. The issue of exercise density is salient because it provides a framework to understand the physiological “supply and demand” mechanisms supporting transient and long-term EF changes. Here, healthy young adults (N=25) completed a non-exercise control condition and conditions involving ten 1-min intervals of metronome-paced leg extensions interspersed with 1- (high-density: HD) and 2-min (low-density: LD) rest intervals. For all conditions, transcranial Doppler ultrasound measured middle cerebral artery velocity (MCAv) to estimate cerebral blood flow (CBF), and EF was assessed pre- and immediately post-intervention via the antisaccade task (saccade mirror-symmetrical to an exogenous target). Results showed that HD and LD conditions elicited comparable and elevated baseline to work interval increases in MCAv (ps<.001); however, only the LD condition yielded a significant reduction in post-intervention antisaccade RTs (p<.001). Moreover, MCAv and antisaccade RT difference scores were not correlated across any experiential condition (ps>.20), indicating that a post-exercise EF benefit is not directly tied to an increase in CBF. Accordingly, results suggest that exercise density moderates post-exercise EF improvements and that the issue of “density” may support developing individualized short- and long-term exercise interventions that benefit EF and brain health.
