Role of Aging and Individual Variation in Exercise Training Responsiveness

The primary purpose of this study is to assess the effects of aging on markers of physical reserve and exercise-induced adaptations in resilience in older adults who completed a structured exercise program within the last 15 years (Parent trial: STRRIDE-PD; NCT00962962). This feasibility pilot study will enroll up to 26 participants to complete a 6-month aerobic exercise intervention.

Inclusion Criteria: * Individuals who completed participation in the STRRIDE-PD trial (NCT00962962) * Body Mass Index (BMI) \> 18 and \< 45 kg/m2 * Stable dose (≥1 month) of any cardiometabolic medications Exclusion Criteria: * Poor vein access * Current use of tobacco or any nicotine products, including e-cigarettes * Insulin-dependent diabetes * Active untreated hypothyroidism with thyroid stimulating hormone (TSH) concentrations \> 10.0 uIU/mL * Systemic inflammatory or connective tissue disease, chronic infectious disease, chronic pulmonary disease or symptomatic cardiovascular disease with positive functional study by ECG or imaging * Current, actively treated malignancy other than dermatologic conditions * Absolute contraindications to exercise testing: ongoing unstable angina; uncontrolled cardiac arrhythmia with hemodynamic compromise; active endocarditis; symptomatic severe aortic stenosis; decompensated heart failure; acute pulmonary embolism, pulmonary infarction, or deep vein thrombosis; acute myocarditis or pericarditis; acute aortic dissection; physical disability that precludes safe and adequate testing * Relative contraindications to exercise testing: known obstructive left main coronary artery stenosis; moderate to severe aortic stenosis with uncertain relation to symptoms; tachyarrhythmias with uncontrolled ventricular rates; acquired advanced or complete heart block; hypertrophic obstructive cardiomyopathy with severe resting gradient; recent stroke or transient ischemic attack; mental impairment with limited ability to cooperate; uncorrected medical conditions, such as hypertension, significant anemia, important electrolyte imbalance, and hyperthyroidism * Modified testing contraindications: acute myocardial infarction (MI) within six months; resting hypertension with systolic or diastolic blood pressures \>160/90 mmHg * Unable to safely participate in an exercise program per study protocol per PI discretion * Planned, intentional weight loss during study