Department of Medicine, Divisions of Nutrition and Preventive Medicine and Preventive Cardiology, Oakland University, William Beaumont School of Medicine, Beaumont Health System, Royal Oak, Michigan, USA.
Obesity (Silver Spring). 2012 Mar;20(3):505-11. doi: 10.1038/oby.2011.262. Epub 2011 Aug 11.
Obese individuals have reduced cardiorespiratory fitness as compared with leaner counterparts. Regular exercise maintains or increases fitness and lean body mass. Lean body mass, in turn, has a direct impact on resting metabolic rate (RMR). Given these relationships, we sought to evaluate the association between RMR and cardiorespiratory fitness in obese individuals. We evaluated 64 obese individuals (78% female) with direct assessment of RMR and cardiorespiratory fitness via breath-by-breath measurement of oxygen consumption and carbon dioxide production at rest and during exercise. The mean age and BMI were 47.4 ± 12.2 years and 47.2 ± 9.2 kg/m(2), respectively. The majority of subjects, 69%, had a measured RMR above that predicted by the Harris-Benedict equation. Compared with the higher RMR group, those with a lower than predicted RMR had increased BMI, with values of 52.9 vs. 44.7 kg/m(2), P = 0.001, respectively. Analysis of those demonstrating significant effort during cardiopulmonary exercise testing (peak respiratory exchange ratio ≥1.10) revealed a significantly higher peak oxygen uptake (VO(2) peak) in the higher RMR group (17.3 ± 3.5 ml/min/kg) compared with the lower RMR group (13.6 ± 1.9 ml/min/kg), P = 0.003. In summary, a lower than predicted RMR was associated with a severely reduced VO(2) peak and a higher BMI in this cohort. These data suggest that morbid obesity may be a vicious cycle of increasing BMI, reduced cardiorespiratory fitness, muscle deconditioning, and lower RMR. Collectively, these responses may, over time, exacerbate the imbalance between energy intake and expenditure, resulting in progressive increases in body weight and fat stores.
肥胖个体的心肺功能健康状况与体型较瘦者相比有所下降。有规律的运动可以维持或提高健康状况和瘦体重。反过来，瘦体重直接影响静息代谢率（RMR）。鉴于这些关系，我们试图评估肥胖个体的 RMR 与心肺功能健康之间的关联。我们评估了 64 名肥胖个体（78%为女性），通过在休息和运动时对氧气消耗和二氧化碳产生进行逐次呼吸测量，直接评估 RMR 和心肺功能健康。平均年龄和 BMI 分别为 47.4±12.2 岁和 47.2±9.2kg/m2。大部分患者（69%）的实测 RMR 高于 Harris-Benedict 方程预测值。与 RMR 较高组相比，RMR 低于预测值组的 BMI 更高，分别为 52.9 和 44.7kg/m2，P=0.001。在心肺运动试验（最大呼吸交换比≥1.10）中显示出明显努力的患者分析显示，RMR 较高组的峰值摄氧量（VO2peak）显著更高（17.3±3.5ml/min/kg），而 RMR 较低组的 VO2peak 更低（13.6±1.9ml/min/kg），P=0.003。总之，低于预测值的 RMR 与本队列中严重降低的 VO2peak 和更高的 BMI 相关。这些数据表明，病态肥胖可能是 BMI 增加、心肺功能健康状况下降、肌肉失健和 RMR 降低的恶性循环。总的来说，这些反应可能会随着时间的推移，加剧能量摄入和消耗之间的失衡，导致体重和脂肪储存的逐渐增加。
