Hemodynamic changes during sleep.

Abstract

Cardiac output, mean arterial pressure, central venous pressure, and the digital plethysmogram were recorded during eeg-monitored sleep. In sleep without rapid eye movements (REM) mean arterial pressure and cardiac output were reduced from the level recorded during the resting awake state. The fall in cardiac output was associated with a reduction in heart rate rather than in stroke volume. Vasodilatation occurred in the digits with decreased amplitude of alpha and beta waves but total peripheral resistance remained essentially unchanged. Central venous pressure fell slightly in stages III and IV sleep. During REM sleep arterial pressure and heart rate usually rose while changes in cardiac output were variable. Digital vasoconstrlction occurred in nearly all instances. The results indicated that the level of sympathetic vasomotor activity had an important influence on the circulatory changes observed during the various stages of sleep.