Physical Activity Is Linked to Greater Moment-To-Moment Variability in Spontaneous Brain Activity in Older Adults.

Agnieszka Z Burzynska,Arthur F Kramer,Jason Fanning,Edward Mcauley,Neha P Gothe,Chelsea N Wong,Gillian E Cooke,Michelle W Voss,J Bruce Morton

doi:10.1371/journal.pone.0134819

Abstract

Higher cardiorespiratory fitness (CRF) and physical activity (PA) in old age are associated with greater brain structural and functional integrity, and higher cognitive functioning. However, it is not known how different aspects of lifestyle such as sedentariness, light PA (LI-PA), or moderate-to-vigorous physical activity (MV-PA) relate to neural activity in aging. In addition, it is not known whether the effects of PA on brain function differ or overlap with those of CRF. Here, we objectively measured CRF as oxygen consumption during a maximal exercise test and measured PA with an accelerometer worn for 7 days in 100 healthy but low active older adults (aged 60–80 years). We modeled the relationships between CRF, PA, and brain functional integrity using multivariate partial least squares analysis. As an index of functional brain integrity we used spontaneous moment-to-moment variability in the blood oxygenation level-dependent signal (SDBOLD), known to be associated with better cognitive functioning in aging. We found that older adults who engaged more in LI-PA and MV-PA had greater SDBOLD in brain regions that play a role in integrating segregated functional domains in the brain and benefit from greater CRF or PA, such as precuneus, hippocampus, medial and lateral prefrontal, and temporal cortices. Our results suggest that engaging in higher intensity PA may have protective effects on neural processing in aging. Finally, we demonstrated that older adults with greater overall WM microstructure were those showing more LI-PA and MV-PA and greater SDBOLD. We conclude that SDBOLD is a promising correlate of functional brain health in aging. Future analyses will evaluate whether SDBOLD is modifiable with interventions aimed to increase PA and CRF in older adults.

Highlights

Higher cardiorespiratory fitness (CRF) and physical activity (PA) in old age is associated with greater brain structural and functional integrity, and higher cognitive functioning [1,2,3]
We found that older adults who spend more time daily on light PA (LI-PA) and moderate-to-vigorous physical activity (MV-PA) had greater SDBOLD in multiple brain regions, and this relationship was positively associated with white matter (WM) microstructure
The analysis yielded one significant latent variables (LVs), suggesting that more LI-PA and MV-PA was related to greater SDBOLD in multiple grey matter (GM) regions (Fig 1A and 1B)

Summary

Introduction

Higher cardiorespiratory fitness (CRF) and physical activity (PA) in old age is associated with greater brain structural and functional integrity, and higher cognitive functioning [1,2,3]. There are three main challenges in understanding how physical health and lifestyle PA relate to brain function in older adults It is not known how non-exercise lifestyle activities, such sedentariness (prolonged and uninterrupted periods of sitting, such as watching TV) or light PA (LI-PA; housework, gardening, relaxed walking) relate to brain function, they account for the majority of daily waking time. This is because lower intensity PA, in contrast to exerciserelated moderate-to-vigorous PA (MV-PA, e.g. jogging, walking stairs, biking), is not well captured by self-reports [4].

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