Sleep Disorders and Cardiovascular Disease

Sleep and heart show a bidirectional relationship, in which sleep disorders influence cardiac function and cardiac pathology may conversely disrupt sleep architecture. Sleep is considered a dynamic process with strong effects on cardiovascular homeostasis. Normally, sympathovagal balance ensures a sympathetic predominance during the day and a prevailing parasympathetic activity during the night; during REM sleep, sympathetic burst occur, leading to blood pressure and heart rate instability. Moreover, many sleep disorders may induce sleep fragmentation, leading to increased sympathetic activity and hypothalamic-pituitary axis hyperactivity; these factors may induce vasoconstriction, increased arterial stiffness, and vascular remodeling. Sleep-disordered breathing is associated with hypertension, congestive heart failure, and cardiac rhythm disturbances. Insomnia and short sleeping time are associated with increased risk of coronary heart disease, hypertension, and heart failure. Sleeprelated movement disorders, namely, periodic limb movements and restless leg syndrome, show a strong relationship with cardiovascular disease, but further studies are needed. Autonomic dysregulation has been described in Idiopathic REM sleep behavior disorder, with possible consequences on cardiovascular function. Narcolepsy type 1 patients show a nocturnal non-dipping profile, resulting from impaired sympathovagal balance.