Inclusion Criteria:  Male or female ≥ 40 and ≤ 80 years old Has a body mass index ≥ 27 and ≤ 47 kg/m^2 Not diagnosed with Type 2 diabetes Not currently engaged in > 60 min/wk of exercise Meet at least 3 of 5 National Cholesterol Education Adult Treatment Panel III Metabolic Syndrome criteria: Increased waist circumference (≥ 102 cm in men; ≥ 88 cm in women) Elevated triglycerides (≥ 150 mg/dl), or on medication for treating the condition Reduced HDL-cholesterol (< 40 mg/dl in men, < 50 mg/dl in women), or on medication for treating the condition High blood pressure (≥ 130 mmHg systolic or ≥ 85 mmHg diastolic), or on medication for treating the condition Elevated fasting glucose (≥ 100 mg/dl), or on medication for treating the condition Subjects currently taking medications that affect heart rate and rhythm (i.e. calcium-channel blockers, nitrates, alpha- or beta-blockers)  Exclusion Criteria:  Morbidly obese patients (BMI > 47 kg/m^2) and overweight/lean patients (BMI < 27 kg/m^2) Evidence of type 1 diabetes and diabetics requiring insulin therapy Subjects who have not been weight stable (> 2 kg weight change in past 3 months) Subjects who have not been recently active (> 30 min of moderate/high intensity exercise, 2 times/week) Subjects who are smokers or who have quit smoking < 5 years ago Subjects prescribed metformin or have taken metformin within 1 year Subjects with abnormal estimated glomerular filtration rate (eGFR) Hypertriglyceridemic (> 400 mg/dl) and hypercholesterolemic (> 260 mg/dl) subjects Hypertensive ( > 160/100 mmHg) Subjects with a history of significant metabolic, cardiac, congestive heart failure, cerebrovascular, hematological, pulmonary, gastrointestinal, liver, renal, or endocrine disease or cancer that in the investigator's opinion would interfere with or alter the outcome measures, or impact subject safety Pregnant (as evidenced by positive pregnancy test) or nursing women Subjects with contraindications to participation in an exercise training program Currently taking active weight suppression medication (e.g. phentermine, orlistat, lorcaserin, naltrexone-bupropion in combination, liraglutide, benzphetamine, diethylpropion, phendimetrazine) Known hypersensitivity to perflutren (contained in Definity microbubbles) Subjects who are considered non-English speaking individuals