The primary goal of this intervention is to determine the efficacy of acute mitochondrial-specific antioxidants to improve vascular endothelial function in middle-aged and older (≥45 y) adults who do no perform regular aerobic exercise. In a double-blind, randomized, placebo-controlled crossover design participants with receive both MitoQ and placebo arm of the study. Primary endpoints will include vascular endothelial function assessed by brachial artery flow-mediated dilation and cardiac function assessed via pulse wave analysis. Secondary endpoints will include measures of aortic stiffness assessed by carotid-femoral pulse wave velocity and carotid artery stiffness (e.g. β-stiffness) and elasticity (carotid compliance, distensibility, and Youngs elastic modulus) from ultrasonography.

Inclusion Criteria:

• Resting brachial blood pressure <160 mmHg (systolic)/<100 mmHg (diastolic)
• Body mass index ≤ 35 kg/m2
• Nonsmoker
• Women must be postmenopausal defined as cessation of menses ≥ 1 year.

Exclusion Criteria:

• cardiovascular/metabolic medications
• known clinical disease
• absolute contraindications to exercise testing

Double-blind, placebo-controlled