title: Modest weight gain is associated with sympathetic neural activation in nonobese humans.
abstract: We tested the hypothesis that modest, overfeeding-induced weight gain would increase sympathetic neural activity in nonobese humans. Twelve healthy males (23 +/- 2 years; body mass index, 23.8 +/- 0.7) were overfed approximately 1,000 kcal/day until a 5-kg weight gain was achieved. Muscle sympathetic nerve activity (MSNA, microneurography), blood pressure, body composition (dual energy X-ray absorptiometry), and abdominal fat distribution (computed tomography) were measured at baseline and following 4 wk of weight stability at each individual's elevated body weight. Overfeeding increased body weight (73.5 +/- 3.1 vs. 78.4 +/- 3.2 kg, P < 0.001) and body fat (14.9 +/- 1.2 vs. 18 +/- 1.1 kg, P < 0.001) in 42 +/- 8 days. Total abdominal fat increased (220 +/- 22 vs. 266 +/- 22 cm(2), P < 0.001) with weight gain, due to increases in both subcutaneous (158 +/- 15 vs. 187 +/- 12 cm(2), P < 0.001) and visceral fat (63 +/- 8 vs. 79 +/- 12 cm(2), P = 0.004). As hypothesized, weight gain elicited increases in MSNA burst frequency (32 +/- 2 vs. 38 +/- 2 burst/min, P = 0.002) and burst incidence (52 +/- 4 vs. 59 +/- 3 bursts/100 heart beats, P = 0.026). Systolic, but not diastolic blood pressure increased significantly with weight gain. The change in MSNA burst frequency was correlated with the percent increase in body weight (r = 0.59, P = 0.022), change in body fat (r = 0.52, P = 0.043) and percent change in body fat (r = 0.51, P = 0.045). The results of the current study indicate that modest diet-induced weight gain elicits sympathetic neural activation in nonobese males. These findings may have important implications for understanding the link between obesity and hypertension.
authors.affiliation: Virginia Polytechnic Institute and State Univ, Dept of Human Nutrition, Foods, and Exercise, Blacksburg, VA 24061, USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Gentile
authors.forename: Jeb S
authors.initials: JS
authors.lastname: Orr
authors.forename: Brenda M
authors.initials: BM
authors.lastname: Davy
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Davy
mesh_terms: D000328:Adult; D004032:Diet; D006801:Humans; D008297:Male; D013564:Sympathetic Nervous System / Q000502:physiology*; D015430:Weight Gain / Q000502:physiology*