Cardiovascular function is regulated by a dynamic balance comprised of sympathetic and parasympathetic influences. Sympathetic regulatory centers include the rostra ventrolateral medulla (RVLM) and paraventricular nucleus of hypothalamus (PVN). Pre-sympathetic neurons (PSNs) in these centers project directly to sympathetic preganglionic neurons in the intermediolateral nucleus of the thoracic spinal cord. Altered function of PSNs along with impaired cardiac vagal activity may lead to autonomic imbalance. Enhanced sympathetic activity has been associated with hypertension, heart failure, stroke and cardiac arrhythmias. In this review, we will discuss the central physiological mechanisms of sympathetic cardiovascular regulation and how alteration in these mechanisms may lead to cardiovascular dysfunction reported in individuals with hypertension and sleep apnea.