Swan P D, Howley E T
Department of Kinesiology, University of Colorado at Boulder 80309.
Int J Obes Relat Metab Disord. 1994 Apr;18(4):263-8.
The present investigation compared the pattern of substrate utilization during prolonged walking in obese women with upper (UB) and lower (LB) body fat patterns and the effect of beta-adrenergic receptor blockade on that response. Twenty healthy, premenopausal, obese volunteers (% fat > or = 30%) were characterized by waist-to-hip (WHR) circumference ratios into two distinct groups (UB: WHR > or = 0.85, LB: WHR < or = 0.75). The groups (n = 10 each) were similar for BMI, age, % fat, and maximal aerobic power (VO2max). Subjects participated in two 60-min walk bouts at 55-60% VO2max. The trials (placebo (C) and 80 mg propranolol (PR)) were performed in random order, 110 min after ingestion, with 2-4 days between tests. Open-circuit spirometry was employed to calculate the VO2, VCO2 and respiratory exchange ratio (RER) at 10 min intervals. A significant (P < 0.0001) decline in RER with time was evident in both trials. However, no group differences existed in RER values during either the C trial (RER range = 0.81-0.88) or the PR trial (RER range = 0.86-0.91). The PR trial induced a 23% reduction in the amount of calories utilized as fat compared to C in both WHR groups. Both groups of women showed equal capabilities for performing prolonged exercise with typical and appropriate metabolic shift in fuel mobilization from carbohydrate to fat. Despite the well-defined differences in metabolic activity of adipose cells shown in vitro, this study indicates that women with significantly different regions of adipose tissue stores have similar physiological potentials for substrate use during exercise.
本研究比较了上半身（UB）和下半身（LB）脂肪分布模式的肥胖女性在长时间步行过程中的底物利用模式，以及β-肾上腺素能受体阻滞剂对该反应的影响。20名健康的绝经前肥胖志愿者（体脂率≥30%）根据腰臀比（WHR）分为两个不同的组（UB：WHR≥0.85，LB：WHR≤0.75）。两组（每组n = 10）在体重指数、年龄、体脂率和最大有氧功率（VO2max）方面相似。受试者以55 - 60% VO2max的强度进行两次60分钟的步行试验。试验（安慰剂（C）和80毫克普萘洛尔（PR））以随机顺序进行，服药后110分钟进行，两次测试之间间隔2 - 4天。采用开路式肺活量测定法每隔10分钟计算一次VO2、VCO2和呼吸交换率（RER）。在两个试验中，RER均随时间显著下降（P < 0.0001）。然而，在C试验（RER范围 = 0.81 - 0.88）或PR试验（RER范围 = 0.86 - 0.91）期间，两组之间的RER值没有差异。与C组相比，PR试验使两个WHR组中作为脂肪利用的热量减少了23%。两组女性在进行长时间运动时，都具有将燃料动员从碳水化合物向脂肪进行典型且适当代谢转换的同等能力。尽管体外研究显示脂肪细胞的代谢活性存在明确差异，但本研究表明，脂肪组织储存区域明显不同的女性在运动期间具有相似的底物利用生理潜能。
