The primary purpose of this study was to measure baroreceptor sensitivity (
BS) during wakefulness and non-rapid eye movement (NREM) sleep in non-apnei
c snoring individuals. To achieve this purpose continuous and simultaneous
measurements of snoring, oxygen saturation, sleep stages, arterial blood pr
essure and heart rate were obtained from seven non-apneic snoring subjects.
After obtaining these measures, a computer program was employed to detect
concomitant increases or decreases in systolic blood pressure and R-R inter
val duration during sequences of three or more consecutive beats that occur
red during stage II and slow wave sleep (SWS), The values recorded from a g
iven sequence were plotted and the slope of the regression line fit to the
data was used as a measure of BS. The results showed that mean arterial pre
ssure and heart rate during stage II and SWS of NREM sleep were not signifi
cantly different from wakefulness. In contrast, the BS measured during NREM
sleep was significantly lower than values recorded during wakefulness. In
addition, linear regression analysis showed that an inverse and significant
correlation existed between snoring frequency and the decrease in BS durin
g sleep, We conclude that the decrease in blood pressure and heart rate nor
mally observed during NREM sleep in healthy non-snoring individuals is atte
nuated or abolished in non-apneic snoring individuals and that these cardio
vascular alterations may be partially mediated by a decrease in BS.