title: Weight loss increases cardiovagal baroreflex function in obese young and older men.
abstract: We tested the hypothesis that reductions in total body and abdominal visceral fat with energy restriction would be associated with increases in cardiovagal baroreflex sensitivity (BRS) in overweight/obese older men. To address this, overweight/obese (25 < or = body mass index < or = 35 kg/m(2)) young (OB-Y, n = 10, age = 32.9 +/- 2.3 yr) and older (OB-O, n = 6, age = 60 +/- 2.7 yr) men underwent 3 mo of energy restriction at a level designed to reduce body weight by 5-10%. Cardiovagal BRS (modified Oxford technique), body composition (dual-energy X-ray absorptiometry), and abdominal fat distribution (computed tomography) were measured in the overweight/obese men before weight loss and after 4 wk of weight stability at their reduced weight and compared with a group of nonobese young men (NO-Y, n = 13, age = 21.1 +/- 1.0 yr). Before weight loss, cardiovagal BRS was approximately 35% and approximately 60% lower (P < 0.05) in the OB-Y and OB-O compared with NO-Y. Body weight (-7.8 +/- 1.1 vs. -7.3 +/- 0.7 kg), total fat mass (-4.1 +/- 1.0 vs. -4.4 +/- 0.8 kg), and abdominal visceral fat (-27.6 +/- 6.9 vs. -43.5 +/- 10.1 cm(2)) were reduced (all P < 0.05) after weight loss, but the magnitude of reduction did not differ (all P > 0.05) between OB-Y and OB-O, respectively. Cardiovagal BRS increased (11.5 +/- 1.9 vs. 18.5 +/- 2.6 ms/mmHg and 6.7 +/- 1.2 vs. 12.8 +/- 4.2 ms/mmHg) after weight loss (both P < 0.05) in OB-Y and OB-O, respectively. After weight loss, cardiovagal BRS in the obese/overweight young and older men was approximately 105% and approximately 73% (P > 0.05) of NO-Y (17.5 +/- 2.2 ms/mmHg). Therefore, the results of this study indicate that weight loss increases the sensitivity of the cardiovagal baroreflex in overweight/obese young and older men.
authors.affiliation: Human Integrative Physiology Laboratory, Dept. of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: Guy E
authors.initials: GE
authors.lastname: Alvarez
authors.forename: Brenda M
authors.initials: BM
authors.lastname: Davy
authors.forename: Tasha P
authors.initials: TP
authors.lastname: Ballard
authors.forename: Stacy D
authors.initials: SD
authors.lastname: Beske
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Davy
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D017704:Baroreflex; D001794:Blood Pressure; D001823:Body Composition; D031204:Caloric Restriction / Q000379:methods*; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000188:drug therapy* / Q000503:physiopathology*; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000503:physiopathology; D015431:Weight Loss