Physical Activity Promotes Higher Cognition in Older Adults

Burzynska et al from the Lifelong Brain and Cognition Lab at the University of Illinois at Urbana report in an article at PLoS One that by looking at functional and structural MRI data found that higher cardiorespiratory fitness (CRF) and physical activity (PA) in old age were associated with greater brain structural and functional integrity, and higher cognitive functioning.

As we age, the physical make up of our brains changes. This includes changes in neural processing in grey matter, but also in the deterioration of structural connections within, which allow communication between distinct brain regions, so that the brain is able to work as a well-wired interconnected network. 

In recent years, researchers have observed that variability in the blood oxygenation as determined by the signal obtained in the BOLD sequence from fMRIs is dependent on functional integrity in certain regions of the brain and is linked to younger age and better cognitive performance..

The researchers collected resting-state fMRI and diffusion images as well as well-normed laboratory measures of fluid intelligence, perceptual speed, episodic memory, and vocabulary from 104 healthy participants (60–80 years).  Because some participants did not complete all tasks in the cognitive battery, a final sample of 91 aging non-demented participants was included in their study.

They also measured CRF as oxygen consumption during a maximal exercise test and measured PA in those healthy but low active older adults with an accelerometer that was worn for 7 days. They modeled the relationships between CRF, PA, and brain functional integrity using multivariate partial least squares analysis. 

As an index of functional brain integrity they used moment-to-moment variability in the blood oxygenation level-dependent signal (SD_BOLD), known to be associated with better cognitive functioning. 

The researchers found that older adults who engaged more in light or moderate-to-vigorous physical activities had greater SD_BOLD in brain regions such as precuneus, hippocampus, medial and lateral prefrontal, and temporal cortices that play a role in integrating segregated functional domains in the brain.

Their findings suggest that engaging in higher intensity physical activity may have protective effects on neural processing in aging. Finally, they demonstrated that older adults with greater overall white matter microstructure were those in whom their cardiovascular and respiratory systems were functioning optimally and they engaged in physical activities. They concluded that greater blood oxygenation as determined by SD_BOLD is a promising correlate of functional brain health and may reflect more flexible or adaptive information processing in older adults. 

PLoS One. 2015 Aug 5;10(8):e0134819

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