The Impact of 6-months of Resistance Training on Brain and Muscle Health in Older Adults With MCI

Physical exercise appears to be effective in preventing transitions from normal cognitive aging to mild cognitive impairments (MCI) and from MCI to dementia-related disorders such as Alzheimer's disease (AD). The investigators will examine the longitudinal effects of progressive resistance training on biomarkers of (neuro)inflammation and neuroplasticity in a cohort of community-dwelling older individuals at high risk of developing MCI. The investigators will focus specifically on the effects of 24 weeks of resistance training on structural and neurochemical properties of the hippocampus and associations between exercise-induced changes in those properties and improvement in functional ability as quantified by pre-to-post changes in the mobility, cognition, psychological and vitality composites of intrinsic capacity (IC). Similarly, the investigators will examine the association between exercise-induced changes in global internal capacity index and exercise-induced changes in the expressions of inflammatory biomarkers (specifically, IL-1β, IL-6, IL-10, IL-18, kynurenine, and TNFa), myokines (specifically, BDNF, IGF-1, irisin), and circulating biomarkers of neurodegeneration (specifically, neurofilament light chain - NfL), tauopathy (specifically, total and phosphorylated tau181) and amyloid pathology (specifically, Aβ42/Aβ40 ratio). Blood samples will be collected between 8 a.m. and 11 a.m. after fasting. Behavioral outcome measures from gait/balance tests, handgrip strength test, cognitive tests, psychological tests, etc. and serum/plasma levels of the circulating biomarkers will be assessed at baseline, mid-intervention time (12 weeks), immediately post-intervention time (24 weeks), and at six-month follow-up (48 weeks). Structural MRI (sMRI) images, diffusion MRI (dMRI) images, resting state functional MRI (rs-fMRI) data and proton magnetic resonance spectroscopy (1H-MRS) data from the brain and T1-wighted images and 1H-MRS spectra from the lower-limb musculature will be collected at baseline and immediately post-treatment time (24 weeks) using a Siemens 3T Skyra scanner. Findings from this study will be used to provide evidence-based frameworks for implementation of longitudinal exercise interventions in prevention of dementia-related neurodegenerative disease among older with MCI. Further, the investigators will assess the effects of exercise on longitudinal changes in muscle mass, muscle strength, and neuromuscular functioning and examine the associations between these changes and exercise induced changes in locomotion capacity and postural stability as well as the prevention of sarcopenia and frailty. Secondary (exploratory) outcome measures will be (1) effects of the longitudinal strength training program on brain structural and neurochemical properties and (2) demographic factors, physiological properties and/or biomarkers that predict response to the intervention.