 Specific Aim 1. Contrast resting and exercise-induced changes in vascular stiffness, endothelial function, and afterload in patients with HFpEF to age-matched controls. Net, mean, and late components of afterload will be assessed by arterial elastance Ea, systemic vascular resistance SVR, and central augmentation index AI. Vascular stiffness will be quantified by pulse wave velocity and total arterial compliance. Stiffness and afterload are dynamically modulated by endothelial and autonomic function, and these responses will be assessed by finger volume plethysmography. Parameters will be measured at rest, during upright cycle ergometry, and immediately post exercise by noninvasive blood pressure, tonometry and comprehensive echo-Doppler examination with tissue Doppler echo TDE. 