Exercise Intolerance in Heart Failure: Did We Forget the Brain?

Abstract

Exercise tolerance is affected in patients with heart failure (HF). Although the inability of the heart to pump blood to the working muscle has been the conventional mechanism proposed to explain the lowered capacity of patients with HF to exercise, evidence suggests that the pathophysiological mechanisms associated with their exercise intolerance is more complex. Recent findings indicate that lowered cerebral blood flow (CBF) and oxygenation likely represent limiting factors for exercise capacity in patients with HF. After an overview of cardiac and peripheral responses during acute and chronic exercise in healthy individuals, we succinctly review cardiac and noncardiac mechanisms by which HF influences exercise tolerance. We then consider how HF, comorbidity, and HF treatment influence CBF and oxygenation at rest and during exercise. Finally, we provide suggestions for further research to improve our understanding of the role of the brain in exercise intolerance in HF.