EFFECT OF WEIGHT-LOSS ON RESTING ENERGY-EXPENDITURE IN HYPERTENSIVE AND NORMOTENSIVE OBESE WOMEN

Hyperinsulinemia and the associated increased sympathetic nervous acti vity have been proposed to implicate in the development of hypertensio n and obesity. The role of hyperinsulinemia in mediated resting energy expenditure (REE) in hypertensive obese subjects is not clear. The ef fect of weight loss on REE between hypertensive and normotensive obese women are also unknown. We measured fasting plasma glucose, insulin, lipids concentrations, REE and body composition by bioelectrical imped ance methods before and after a weight loss program in 9 newly diagnos ed hypertensive and 10 normotensive obese women. As compared with age- matched lean control women (n=14), obese subjects had higher fasting p lasma glucose, insulin concentrations and REE values. However, these v ariables were not different between obese groups. Although REE and fas ting plasma insulin concentrations correlated well in simple correlati on (r=0.708, p<0.001), this relationship disappeared after adjusting f or values of fat free mass (FFM). Weight loss for approximately 10% of initial weight led to significant decreases of blood pressure and fas ting plasma insulin concentrations in both obese groups. Fasting plasm a cholesterol, LDL cholesterol and triglyceride concentrations decreas ed in hypertensive obese individuals. Significant fall of REE in hyper tensive group (p<0.05) and normotensive group (p<0.02) were observed f ollowing weight loss. However, the ratio of REE to FFM decreased signi ficantly only in hypertensive subjects (114.6+/-5.2 KJ/day . Kg(-1) to 107.2+/-14.6 KJ/day . Kg(-1), p<0.05). In conclusion, obese women, ei ther hypertensive or normotensive, had higher fasting plasma insulin c oncentrations and REE than those of lean controls, although these vari ables were not different between obese groups. No significant relation between fasting plasma insulin and REE could be found. Weight loss pr oduced a significant decrease of REE/FFM only in hypertensive obese wo men. Further study to evaluate the effect of weight loss on energy exp enditure in hypertensive obese subjects is necessary.