Reshaping the Path of Mild Cognitive Impairment by Refining Exercise Prescription

Dementia is one of the most pressing health care issues of the 21st century. Evidence suggests that exercise enhances cognitive function in healthy older adults. Most research has focused on aerobic training (AT). Therefore, investigators aim to assess the individual effects of AT and resistance training (RT), as well as the interaction effect of combining the two types of exercise training, on cognitive function in older adults with mild cognitive impairment.

Investigators will conduct a 6-month assessor-blinded randomized-controlled trial of 216 community-dwelling adults with mild cognitive impairment. Individuals will be randomized to one of four experimental groups, all which receive 6 months of exercise classes four times per week: 1) combined aerobic training and resistance training; 2) aerobic training; 3) resistance training; or 4) balance and toning exercise. There will be two measurement sessions: baseline and 6 months (end of intervention period). A 12-month followup (i.e., 18 months from baseline) measurement will be done for a sub-set of participants.

Eligibility Criteria:
Inclusion Criteria:

* Community-dwelling in Metro Vancouver
* Have subjective memory complaints, defined as the self-reported feeling of memory worsening with an onset within the last 5 years, as determined by interview and corroborated by an informant
* Have a baseline Montreal Cognitive Assessment (MoCA) score \< 26/30
* Mini-Mental State Examination (MMSE) score = or \> 22 at screening
* Read, write, and speak English
* Not expected to start or are stable on a fixed dose of anti-dementia medications (e.g., donepezil, galantamine, etc.) during the 6-month intervention period
* Able to walk independently
* Must be in sufficient health to participate in the exercise programs
* Able to comply with scheduled visits, treatment plan, and other trial procedures
* Provide a personally signed and dated informed consent document indicating that the individual (or a legally acceptable representative) has been informed of all pertinent aspects of the trial. In addition, an assent form will be provided at baseline and again at regular intervals

Exclusion Criteria:

* Engaged in moderate (e.g., brisk walking) physical activity \> 1 time per week, or \> 60 minutes per week, in the 3 months prior to study entry
* Diagnosed with dementia of any type
* Clinically suspected to have neurodegenerative disease as the cause of mild cognitive impairment (MCI) that is not Alzheimer's Disease (AD), vascular cognitive impairment (VCI), or both (e.g., multiple sclerosis, Parkinson's disease, Huntington's disease, frontotemporal dementia)
* At high risk for cardiac complications during exercise or unable to self-regulate activity or to understand recommended activity level; 5) have clinically important peripheral neuropathy or severe musculoskeletal or joint disease that impairs mobility, as determined by his/her family physician
* Taking medications that may negatively affect cognitive function, such as anticholinergics, including agents with pronounced anticholinergic properties (e.g., amitriptyline), major tranquilizers (i.e., typical and atypical antipsychotics), and anticonvulsants (e.g., gabapentin, valproic acid)
* On any hormone therapy (estrogen, progesterone, or testosterone) in the last 24 months
* Planning to participate, or already enrolled in, a concurrent clinical drug or exercise trial