Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia.
Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia.
Am J Med. 2014 May;127(5):436-42. doi: 10.1016/j.amjmed.2014.02.003. Epub 2014 Feb 11.
High levels of obesity among African American women have been hypothesized to be partially resultant from a lower resting metabolic rate compared with white women. The aim of the current study was to determine if differences in cardiorespiratory fitness and moderate-to-vigorous physical activity are associated with differences in resting metabolic rate among free-living young adult African American women and white women.
Participants were 179 women (white women n = 141, African American women n = 38, mean age = 27.7 years). Resting metabolic rate was measured using indirect calorimetry, body composition using dual energy x-ray absorptiometry, cardiorespiratory fitness via maximal treadmill test, and moderate-to-vigorous physical activity using an activity monitor.
African American women had higher body mass index, fat mass, and fat-free mass compared with white women but lower levels of cardiorespiratory fitness. No differences were observed between African American and white women in resting metabolic rate when expressed as kcal/day (1390.8 ± 197.5 vs 1375.7 ± 173.6 kcal/day, P = .64), but African American women had a lower resting metabolic rate when expressed relative to body weight (2.56 ± 0.30 vs 2.95 ± 0.33 mL/kg/min, P < .001). After statistical adjustment for differences in body composition between groups using linear regression models, African American women had a lower resting metabolic rate compared with white women (1299.4 ± 19.2 vs 1400.4 ± 9.2 kcal/day, P < .001). The addition of cardiorespiratory fitness reduced the differences among groups by 25%. The addition of moderate-to-vigorous physical activity did not improve the model.
The present study confirms that African American women have a lower resting metabolic rate compared with their white peers, and low cardiorespiratory fitness explained 25% of this difference. Variables associated with resting metabolic rate, such as cardiorespiratory fitness, represent possible points of tailored interventions designed to address high levels of obesity seen in certain demographic groups.
据推测，非裔美国女性的肥胖水平较高，部分原因是与白人女性相比，她们的静息代谢率较低。本研究的目的是确定在自由生活的年轻非裔美国女性和白人女性中，心肺功能和中高强度体力活动的差异是否与静息代谢率的差异相关。
参与者为 179 名女性（白人女性 n=141 名，非裔美国女性 n=38 名，平均年龄=27.7 岁）。使用间接热量法测量静息代谢率，使用双能 X 射线吸收仪测量身体成分，使用最大跑步机测试测量心肺功能，使用活动监测器测量中高强度体力活动。
非裔美国女性的体重指数、脂肪量和去脂体重均高于白人女性，但心肺功能较低。非裔美国女性和白人女性的静息代谢率以千卡/天表示时无差异（1390.8±197.5 与 1375.7±173.6 千卡/天，P=0.64），但以相对体重表示时，非裔美国女性的静息代谢率较低（2.56±0.30 与 2.95±0.33 毫升/千克/分钟，P<0.001）。使用线性回归模型对组间身体成分差异进行统计学调整后，非裔美国女性的静息代谢率仍低于白人女性（1299.4±19.2 与 1400.4±9.2 千卡/天，P<0.001）。心肺功能的增加降低了组间 25%的差异。中高强度体力活动的增加并不能改善模型。
本研究证实，与白人同龄人相比，非裔美国女性的静息代谢率较低，而低心肺功能解释了这种差异的 25%。与静息代谢率相关的变量，如心肺功能，代表了针对某些特定人群肥胖水平较高的潜在干预点。
