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

AimFat 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 (Lipoxmax) that elicits the maximum lipid oxidation rate in normal-weight women.MethodsTwenty-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]. Lipoxmax 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.ResultsThe two groups did not differ in aerobic fitness, total fat mass, or total and localized fat-free mass. Lipoxmax and MLOR were significantly lower in H-A/LB vs L-A/LB women (43 ± 3% VO2maxvs 54 ± 4% VO2max, and 4.8 ± 0.6 mg min−1 kg FFM−1vs 8.4 ± 0.9 mg min−1 kg FFM−1, respectively; P < 0.001). Total and abdominal fat mass measurements were negatively associated with Lipoxmax (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].ConclusionThese 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.