ELEVATED BLOOD PRESSURES IN OBESE YOUNG MEN WITH MILD HYPERTENSION ARE SUSTAINED DURING THE DAY AND NIGHT

The major goal of this study was to determine if the elevated blood pr essures in obese men <45 years old with mild hypertension persist outs ide the clinic. A secondary aim was to determine if hyperinsulinemia i s associated with accentuated diurnal changes of blood pressure. To ad dress these objectives, the clinic and ambulatory blood pressures as w ell as a 75-g, 2-h oral glucose tolerance test measurements were obtai ned from 9 lean normotensive, 9 lean hypertensive, and 22 obese hypert ensive men <45 years old. The week before study, volunteers ate an iso caloric diet with 220 mEq of NaCl/day. Obese hypertensives, subdivided by high (n = 11) and low (n = 11) insulin areas-under-the-curve (AUCs ) in response to oral glucose, and lean hypertensives maintained highe r ambulatory blood pressure than lean normotensives (130 +/- 3/74 +/- 1, 136 +/- 4/78 +/- 2, 132 +/- 5/77 +/- 3 v 118 +/- 4/65 +/- 2 mm Hg, respectively, P < .05). As expected, the insulin AUC during the glucos e tolerance test was higher in obese hypertensives with higher insulin AUCs than in obese hypertensives with lower insulin AUCs, lean hypert ensives, or lean normotensives (13.9 +/- 1.2 v 7.9 +/- 0.3, 7.2 +/- 0. 7, 5.7 +/- 0.7 mU-min/dL, P < .05). Insulin AUCs were not significantl y different in obese hypertensives with lower insulin levels, lean hyp ertensives, or lean normotensives. The diurnal increases of systolic a nd diastolic blood pressure as well as heart rate and pressure-rate pr oduct were similar in all four groups. The higher laboratory blood pre ssure in obese men <45 years old is maintained during both the day and night relative to values obtained in lean normotensives and comparabl e to pressures observed in lean hypertensives. However, the level of h yperinsulinemia in the obese young men in this study is not associated with either significant differences in blood pressure, heart rate, an d pressure-rate product values during the day or night or significantl y different changes in these same variables between daytime and nightt ime values.