Prefrontal Cortex Oxygenation During Exercise in Older Adults with Motoric Cognitive Risk Syndrome

Motoric cognitive risk syndrome (MCR) is a pre-dementia syndrome characterized by subjective memory complaints and gait impairments that may be related to lower prefrontal cortex (PFC) function. Acute bouts of aerobic exercise are shown to improve PFC function, however, the acute effects of exercise on PFC oxygenation have not yet been examined in MCR. This study aims to characterize the PFC oxygenation responses during acute exercise in older adults with MCR. Nineteen older adults with MCR performed a submaximal cycling exercise protocol. Functional near-infrared spectroscopy (fNIRS) is used to measure concentrations of oxygenated (OxyHb) and deoxygenated (DeoxyHb) hemoglobin from the PFC. There is a trend for increased OxyHb concentrations and decreased DeooxyHb concentrations during exercise. Exercise also induced significant increases in ratings of perceived exertion (RPEs) and heart rate. A significant, positive correlation between PFC OxyHb and RPEs during the cycling exercise are also observed. The findings reveal that PFC oxygenation increases during exercise in an intensity-dependent manner and the subjective perception of exertion is associated with the magnitude of PFC oxygenation. These results suggest that moderate-intensity cycling exercise may have beneficial effects on increasing cerebral blood flow in the PFC of older adults with MCR.