The role of norepinephrine in exercise impairment in congestive heart failure

Congestive heart failure is a disorder that includes a multitude of neurohormonal responses that become maladaptive over time. Chronic sympathetic stimulation adversely affects the well-being and survival of heart failure patients and contributes to the exercise intolerance frequently seen in these patients. Norepinephrine levels have been correlated with poorer survival in heart failure patients. Administration of norepinephrine has been shown to impair exercise responses in those with congestive heart failure, and the recent effort to incorporate beta blocker therapy into the standard management of heart failure patients addresses this abnormal neurohormonal process. Studies with central-acting sympatholytics have shown mixed results. The use of drugs such as clonidine has been suggested as potentially useful therapy in the long-term management of patients with heart failure, but definitive conclusions await further study. Regular exercise has been shown to reduce resting norepinephrine levels in heart failure subjects. This may serve as an additional rationale to recommend chronic exercise for these patients.