Ambulatory blood pressure in obstructive sleep apnea syndrome

38 patients with obstructive sleep apnea syndrome underwent automated ambulatory 24-hour blood pressure monitoring. Systolic, diastolic and mean pressure values were significantly correlated with the apnea index (AI) during sleep, as well as during wakefulness. A significant negative correlation was found between minimal arterial O2 saturation in sleep and diastolic blood pressure values during waking hours. The contribution of the AI to blood pressure during sleep and wakefulness was significant, while the contribution of body mass index (BMI) was negligible. These results support the causal relationship between the severity of sleep apnea syndrome and systemic hypertension, independent of BMI.