Effect of age, sex and aerobic exercise on cerebrovascular regulation in older adults: Results from the Brain in Motion Study
Date
2019-09-17
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Abstract
Background: By 2024, 20% of Canada’s population will be 65 and older. Aging is associated with progressive declines in cerebrovascular and cognitive function and an increased prevalence of age-related diseases such as Alzheimer’s Disease (AD). Physical activity has been associated with improvements in cerebrovascular function and cognitive performance, and may help to prevent and/or delay AD. However, the underlying time-course by which enhanced physical activity may be protective for brain health and differences between men and women is poorly understood. Objective: To determine the influence of age and sex on the cerebrovascular responses to submaximal exercise and euoxic hypercapnia in older adults. Furthermore, this study assessed the effects of a 6-month aerobic exercise intervention on cerebrovascular measures and evaluated outcomes after three and six months of exercise. Design: 202 participants aged 66.5 ± 6.5 years (mean ± SD, 101 females) completed the aerobic exercise intervention. Measurements took place pre-, mid- and post-intervention including demographic information, maximal aerobic capacity (VO2max) and cerebrovascular function. Linear mixed models adjusted for covariates were used to measure the physiological responses to submaximal exercise and euoxic hypercapnia pre-intervention and the changes in middle cerebral artery peak blood flow velocity (VP), mean arterial pressure (MAP) and cerebrovascular resistance (CVRi) and conductance (CVCi) indices after three and six months of aerobic exercise. Results: Pre-intervention, both age and sex were significant predictors of VP (p=0.002; p<0.010), CVRi (p<0.001; p=0.029), and CVCi (p<0.001; p=0.004) during exercise. Compared to rest, acute exercise led to increases in VP, CVRi and MAP and decreases in CVCi (p<0.001). Three months of aerobic exercise led to increases in VP (p=0.005) and CVCi (p=0.021) and decreases in CVRi (p=0.002) in women only, with no further changes observed after an additional three months of exercise. Conclusion: Male sex and increasing age were associated with lower VP, CVCi and higher CVRi. Three months of aerobic exercise led to improvements in cerebrovascular measures in women that were maintained in the latter three months of the intervention in healthy, older adults. Such results have important implications for the role of physical activity in improving health outcomes and the differences observed with aging and sex.
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Keywords
cerebrovascular function, aging, sex differences, aerobic exercise
Citation
Wyer, L. (2019). Effect of age, sex and aerobic exercise on cerebrovascular regulation in older adults: Results from the Brain in Motion Study (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.