Effects of adipose tissue distribution on maximum lipid oxidation rate during exercise in normal-weight women

Aim. - Fat mass localization affects lipid metabolism differently at rest and during exercise in overweight and normal-weight subjects. The aim of this study was to investigate the impact of a low vs high ratio of abdominal to lower-body fat mass (index of adipose tissue distribution) on the exercise intensity (Lipox(max)) that elicits the maximum lipid oxidation rate in normal-weight women. Methods. - Twenty-one normal-weight women (22.0 +/- 0.6 years, 22.3 +/- 0.1 kg.m(-2)) were separated into two groups of either a low or high abdominal to lower-body fat mass ratio [L-A/LB (n = 11) or H-A/LB (n = 10), respectively]. Lipox(max) and maximum lipid oxidation rate (MLOR) were determined during a submaximum incremental exercise test. Abdominal and lower-body fat mass were determined from DXA scans. Results. - The two groups did not differ in aerobic fitness, total fat mass, or total and localized fat-free mass. Lipox(max) and MLOR were significantly lower in H-A/LB vs L-A/LB women (43 +/- 3% VO2max vs 54 +/- 4% VO2max, and 4.8 +/- 0.6 mg min(-1) kg FFM-1 vs 8.4 +/- 0.9 mg min(-1) kg FFM-1, respectively; P < 0.001). Total and abdominal fat mass measurements were negatively associated with Lipox(max) (r=-0.57 and r= -0.64, respectively; P < 0.01) and MLOR [r = -0.63 (P < 0.01) and r=-0.76 (P < 0.001), respectively]. Conclusion. - These findings indicate that, in normal-weight women, a predominantly abdominal fat mass distribution compared with a predominantly peripheral fat mass distribution is associated with a lower capacity to maximize lipid oxidation during exercise, as evidenced by their lower Lipoxmax and MLOR. (C) 2014 Elsevier Masson SAS. All rights reserved.