Sympathetic nerve activity, stress, and cardiovascular risk

Abstract

Recent discoveries supporting a functional and structural link between the brain and the heart emphasize the importance of understanding the cross talk for cardioand cerebrovascular health. Stress has been shown to play a crucial role in the generation of cardiovascular diseases and has a major impact on neurodegenerative diseases and mental disorders presumably through activation of the sympathetic branch of the autonomic nervous system. It is well established that overactivity of the sympathetic nervous system plays a central role in the development of cardiovascular disease and constitutes an important risk factor for cardiovascular morbidity and mortality. Further, increasing evidence suggests the overactivity of the sympathetic branch is a common phenomenon linking major cardiac pathologies seen in association with several primarily neurological conditions, such as cerebral infarction and subarachnoid hemorrhage. Modulating brain activity in humans for otherwise treatment resistant disorders has been demonstrated to affect cardiovascular parameters. Direct electrical stimulation of specific midbrain areas in humans for pain relief regulates human cardiovascular reflex control and can evoke panic and anxiety, by modulating the activity of the autonomic nervous system. This chapter examines the connection between the brain and the heart the autonomic nervous system provides. Evidence of a linking between emotional stresses and cardiovascular risk is explored, more specifically, stress-induced cardiomyopathy and a plausible explanation for the female predisposition of the condition.