People with vascular conditions are at risk of having memory problems, and these memory problems increase the risk for further cognitive decline. Brain stimulation has been used to improve mood and memory. Transcranial direct current stimulation (tDCS) is believed to work best on brain cells that are active or "primed" before stimulation. The purpose of this study is to compare the effects of exercise and tDCS on memory performance in patients who have completed cardiac rehabilitation and are at risk of cognitive decline.

Vascular disease is a major risk factor and contributor to dementia. Current interventions to manage vascular risk factors have mixed results. Presently, there are no consistently effective treatments targeting vascular cognitive impairment no dementia.

Study Aim: To evaluate the effect of exercise-primed tDCS on global cognition.

Study Design: Eligible participants will be randomized to one of four interventions: Exercise primer with tDCS, Treatment as usual (TAU/exercise education) with tDCS, or Exercise primer with sham tDCS, Treatment as usual with sham tDCS. Participants randomized to an exercise group will undergo exercise, followed by either sham or active tDCS. Participants randomized to TAU will receive written information in accordance with the Canadian Physical Activity Guidelines for older adults and tDCS or sham. Cognition, behaviour, neuroimaging and blood biomarkers will be measured.

Inclusion Criteria:

• ≥50 years of age; females must be post-menopausal
• Presence of cerebrovascular and/or cardiovascular risk factors or coronary artery disease
• Montreal Cognitive Assessment (MoCA) <27
• Sufficiently proficient in English
• Must be able to exercise at a moderate intensity level
• Presence of modest deficits (1 standard deviation below population norm) in one of the following domains: executive function, verbal memory, working memory, or visuospatial memory

Exclusion Criteria:

• History of stroke
• Change in psychotropics within the last 4 weeks
• Current benzodiazepine use due
• Metal implants that would preclude safe use of tDCS or neuroimaging
• Significant neurological or psychiatric conditions (current major depressive disorder, bipolar disorder, schizophrenia)
• MoCA <18 and/or clinical diagnosis of dementia
• Any medical contraindications to exercise

Participants, outcomes assessors, and investigators will be blinded to stimulation type.