The purpose of this study was to examine the relationship between snoring and mean arterial blood pressure during sleep. This was accomplished by performing continuous, all-night, simultaneous measurements of snoring, oxygen saturation, sleep stages, and arterial blood pressure in a group of eight snorers and five nonsnoring control subjects. The results were analyzed to determine whether changes in mean arterial blood pressure during non-rapid-eye-movement (non-REM) sleep are different in snorers from those in nonsnorers and whether they are related to nocturnal hypoxemia. Both groups were similar with respect to their anthropometric parameters and sleep architecture. Oxygen saturations during different stages of non-REM sleep were similiar within each group. However, the analysis of variance revealed that among snorers mean arterial blood pressure increased slightly during slow-wave sleep, whereas the nonsnorers reduced their blood pressure by 17.4 +/- 3.7% compared with wakefulness values. We also performed multiple linear regression analysis for the entire group of 13 subjects using the change in mean arterial blood pressure relative to wakefulness as the dependent variable and snoring frequency and mean arterial oxygen saturation as the independent variables; the results demonstrated that only snoring frequency, and not oxygen saturation, correlated significantly with the change in mean arterial blood pressure. We conclude that snoring may influence variation of blood pressure during sleep, preventing the normally observed reduction of arterial blood pressure associated with slow-wave sleep.