BACKGROUND: Patients with heart failure with preserved ejection fraction (HFpEF) exhibit a range of cardiovascular phenotypic profiles modified by several common comorbidities. In particular, patients with HFpEF tend to be older; however, it is unclear whether the effects of cardiovascular aging per se modify the expression of HFpEF. We therefore sought to investigate the interaction between age and physiologic profile in patients with HFpEF. METHODS AND RESULTS: We assessed the hemodynamic and metabolic profile of 40 patients with HFpEF. Patients underwent right heart catheterization at rest and during supine cycle ergometry, and were segregated into 2 groups by the median age of the cohort. Older patients with HFpEF demonstrated reduced resting cardiac output (4.8±1.2 L/min versus 5.7±1.1 L/min). With exercise, older patients demonstrated a marked rise in arteriovenous oxygen content difference (10.8±1.8 versus 7.9±2.4 mL, P≤0.001), driven by enhanced oxygen extraction. There was no significant difference in peak pulmonary capillary wedge pressure (30±7 mm Hg versus 27±6, P=0.135), including when indexed to workload (pulmonary capillary wedge pressure/W, 0.88 mm Hg/W versus 0.92; P=0.83). CONCLUSIONS: Older patients with HFpEF display a different physiological phenotype compared with younger patients, with enhanced oxygen extraction and lower increment in cardiac output to increase oxygen consumption from rest to peak supine exercise. This finding highlights the importance in considering age when considering therapeutic options in patients with HFpEF. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.