The frequent association of sleep apnea syndrome and essential hypertension led to think of sleep apnea as an etiology of hypertension, especially as a good correlation has been found between the severity of both diseases. Moreover, treating the apnea syndrome results in a decrease of blood pressure. The aim of our study is to depict the outlines of a severe hypertensive individual with sleep apnea by comparing 9 men primarily referred to the hypertension clinic with refractory hypertension and finally found to have sleep apnea (study group) to 23 men whose diagnosis of sleep apnea was made in the pulmonary unit (controls). Fifteen of these were hypertensives. Mean age of the study group was 47 +/- 7 years vs 60 +/- 11. Controls were less overweighted: BMI = 33 +/- 6 kg/m3 vs 39 +/- 5. Mean blood pressure was 171 +/- 16/107 +/- 4 mmHg in the study group vs 157 +/- 19/92 +/- 12 mmHg in controls. Prevalence of glucose metabolism disorders was significantly greater in the study group: 6 patients with maturity onset diabetes and 3 with proven glucose intolerance, vs respectively 4 and 6 controls. Triglycerides were elevated in both groups whereas mean cholesterol was slightly above normal values. Six patients of the study group could have an echocardiogram which showed left ventricular hypertrophy (mean left ventricular mass index = 206 +/- 31 g/m2 after the Penn convention).(ABSTRACT TRUNCATED AT 250 WORDS)