Systemic hypertension in sleep apnea syndrome. Relationship with sleep architecture and breathing abnormalities. To examine the possible relationship between systemic HT and SAS we compared 21 hypertensive (HT+) and 29 normotensive (HT-) patients for morphologic characteristics, sleep disturbances and respiratory events monitored during a full night polysomnography. There was no significant difference between HT+ and HT- patients with respect to age, weight, BMI, sleep stage distribution and disorganization, apnea-hypopnea index (number of episodes per hour of sleep) and duration (minutes per hour of sleep) nor O2 saturation indices: mean nocturnal and minimum O2 saturation. We conclude therefore that HT in SAS patients is not directly related to morphologic characteristics, sleep disturbances and breathing abnormalities. 