Effects of aerobic exercise and sleep on older adults’ proteomic profile, and cerebrovascular health

For the first time in history, older adults above the age of 65 years are projected to outnumber those under the age of 18. Aging is the primary risk factor for cardiovascular disease, neurodegenerative disorders, and obstructive sleep apnea (OSA), the most common sleep-related breathing disorder. A better understanding of relationships between lifestyle interventions such as sleep and exercise, and brain and blood biomarkers of health might indicate how changes in physical health can be beneficial to maintain and/or improve cerebrovascular health with aging. This thesis examined the effects of a six-month aerobic exercise intervention called the Brain in Motion Study (BIM) on plasma proteomics, and cerebrovascular health in community dwelling older adults. In the first study, we identified a protein panel signature in 12 female, and 12 male BIM I participants over 5-years, that correlates to longitudinal changes in cognition and sleep. The second study is a cross-sectional investigation of the relationships between sleep spindles, sleep disordered breathing indices of obstructive sleep apnea (OSA), and brain structure, using MRI, in 71 BIM participants. Finally, we investigated sex-specific effects of aerobic exercise on cerebral perfusion of the hippocampus, insula, and left pars triangularis, brain regions involved in verbal fluency, in 27 BIM I participants. These studies highlight the importance of reducing inflammation with aging, potentially through improving sleep and cardiorespiratory fitness. While OSA is prevalent in community dwelling older adults, cerebral perfusion may be protected in untreated OSA. We found that thalamic volume was positively associated with spindle frequency, suggesting that there may be a structural component to sleep architecture. In terms of implementing aerobic exercise as an intervention to improve cerebrovascular health, sex differences should be considered.