Neurophysiological Mechanisms of Physical Activity Interventions in Unique Environments

Research has yet to determine how regular physical activity in different environments influences physical and cognitive performance. Studies show exposure to natural environments can improve cognitive performance, increase creative thinking, and decrease stress-related responses. According to the theory of attention restoration, exposure to natural environments restores attentional resources because nature contains specific qualities that allow for directed attention to replenish and endorses health-related behaviors such as walking, running, and biking. Nature exposure is hypothesized to decrease activation of neural networks involved in cognitive control, therefore allowing for restoration of resources to occur. Activation of the cognitive control network is reflected through increased power of theta frequency (4-8 Hz) at the midfrontal regions (measured using electroencephalography; EEG), which reflects cognitive fatigue during rest. Previous research shows spending time in nature decreases midfrontal theta power, therefore reducing rumination and cognitive fatigue. Likewise, event-related potentials, such as higher P3 amplitude and shorter P3 latency during tasks, indicate better attentional allocation and processing speed, indicating better cognitive processing. These neurophysiological measurements are indicative of cognitive restoration and can determine changes in cognitive functioning over time.

The investigators propose to collect measurements of electroencephalography (spectral EEG, task-evoked event-related potentials), behavioral cognitive assessments (cognitive control, working memory performance), and health factors (VO2max) using a 2 (nature or urban physical activity intervention) x 2 (baseline and post-intervention sessions) design to determine changes in cognitive functioning across time. As part of an ongoing investigation in the cognitive and physical influence of intervention strategies, physical activity interventions will take place for a 6-week period, and participants will be recruited across three intervals of testing. Trained fitness instructors will lead participants in regularly scheduled 45-minute aerobic-based physical activity sessions three times a week. Each session will involve a combination of walking and running that progressively increases the duration of intensity throughout the 6-week period, starting at 20-minutes of moderate-to-vigorous training during the first week, and increasing duration by 5-minute intervals. Intervention groups will differ based on the location of the intervention. The nature-based intervention sessions will occur outdoors in a local public park in the Boston area. The urban-based intervention sessions will occur indoors in the Center for Cognitive & Brain Health intervention activity rooms.