Frequently patients are subjected to stress echocardiography, which involves the above assessment of diastolic function during exercise.[39] This is undertaken because perturbations in diastole are exaggerated during the increased demands of exercise. Exercise requires increased left ventricular filling and subsequent output. Typically the heart responds by increasing heart rate and relaxation time.[40] However, in patients with HFpEF both responses are diminished due to increased ventricular stiffness.