What Muscle Signals Mediate the Beneficial Effects of Exercise on Cognition?

Cumulative evidence indicates that physical exercise has positive effects on cognitive functions. Physical activity decreases the rate of cognitive decline both in healthy people and in people with neurodegenerative disorders across the lifespan.^1-5 Moderate-to-vigorous physical activity has been shown to be associated with improved learning and memory,^1,6,7 executive functions,⁸ and reaction time.⁹ A recent longitudinal population-based study including 2,060 cognitively unimpaired men and women aged 70 years or older showed that light-intensity midlife physical activity was associated with less decline in memory function, and vigorous late-life physical activity was associated with less decline in language, attention, and global cognition compared with the no physical activity reference group.¹⁰ Physical activity has also been associated with a reduced risk of dementia among individuals with mild cognitive impairment (MCI).¹¹ Aerobic exercise has beneficial effects on cognitive symptoms in Alzheimer disease (AD),^12-14 frontotemporal dementia,¹⁵ and Parkinson disease (PD).^16-19 For example, randomized controlled trials show that physical exercise improved cognition in both AD and MCI groups, with an effect size similar to that of donepezil.²⁰ In patients with PD, aerobic exercise increased functional connectivity of the anterior putamen with the sensorimotor cortex and functional connectivity in the right frontoparietal network, stabilizing disease progression in the corticostriatal sensorimotor network and enhancing cognitive performance.²¹ Exercise training program also had positive effects on prefrontal activity and gait performance.²²