Asymptomatic Carotid Stenosis and Mobility Function With Exercise Intervention

Inclusion Criteria: * Eligible patients will be at least 18 years of age and will have asymptomatic 50-69% carotid stenosis * Asymptomatic status will be confirmed as in NIH trials on asymptomatic carotid stenosis, by medical history, physical examination, and the National Institutes of Health Stroke Scale (NIHSS) * Stenosis severity will be determined by duplex sonography, MR angiography, or CT angiography Exclusion Criteria: * previous stroke or transient ischemic attack * occlusion or severe stenosis of the non-index carotid artery * planned carotid revascularization * persons advised by their doctor not to exercise * a medical condition that precludes the ability to ambulate * exercise or reduces the likelihood of follow-up * evidence of a medical condition that would lead to an increased risk of accident, injury, or illness as a result of the proposed testing or intervention * orthostatic hypotension * severe medical illness that interferes with the evaluation of outcomes * uncorrected visual impairment or eye surgery in the past 6 months * patients that are unable to undergo PW-MRI due to gadolinium contrast allergy or renal insufficiency will also be excluded * given the possibility that comorbid cognitive impairment may influence balance and mobility function, subjects with any documented medical history of dementia or cognitive impairment or those unable to follow commands will be excluded from the study * In addition, subjects with other neurological conditions such as Parkinson's, peripheral neuropathy or myopathy, sedative medications, and major depression (Center for Epidemiological Studies Depression Survey Score \>16) will be excluded * in order to avoid ceiling effects of the Mini BESTest, potential subjects will be prescreened for balance dysfunction using a 10-second Single Leg Stance Test * those that are able to complete the test without losing balance on either side will be excluded from the study * the investigators will exclude subjects that participate in structured aerobic exercise routinely greater than three times per week within a month of starting the study