Browning Raymond C, Kram Rodger
Department of Integrative Physiology, 354 UCB, University of Colorado, Boulder, CO 80309, USA.
Obes Res. 2005 May;13(5):891-9. doi: 10.1038/oby.2005.103.
We tested the hypotheses that walking is more expensive for obese women, and they prefer slower walking speeds that minimize the gross energy cost per distance despite a greater relative aerobic effort [percent of maximal oxygen uptake (Vo(2max))/kg].
Twenty adult women, 10 obese (BMI = 34.1 +/- 3.2 kg/m(2)) and 10 normal weight (BMI = 20.4 +/- 2.1 kg/m(2)) volunteered. To determine the metabolic rate and energy cost per distance vs. speed relationships, we measured Vo(2) and V(CO(2)) while subjects walked on a treadmill at six speeds (0.50, 0.75, 1.0, 1.25, 1.5, and 1.75 m/s; 5-minute trials, with a 5-minute rest period between trials). We measured preferred walking speed on a 50-m section of level sidewalk and Vo(2max) using a modified Balke treadmill protocol.
Walking was 11% more expensive for the obese subjects, but they preferred to walk at similar speeds as normal weight subjects (1.40 vs. 1.47 m/s, p = 0.07). Both groups preferred walking speeds at which their gross energy cost per distance was almost minimized. Obese subjects had a smaller Vo(2max)/kg, so they required a greater relative aerobic effort at the preferred speed (51% vs. 36%, p = 0.001).
Obese women preferred a walking speed that minimized energy cost per distance, even though this strategy required a greater relative aerobic effort than walking more slowly. Our results suggest that walking slower for a set distance may be an appropriate exercise recommendation for a weight management prescription in obese adults.
我们检验了以下假设，即步行对肥胖女性来说成本更高，并且她们更喜欢较慢的步行速度，这种速度能使每单位距离的总能量消耗最小化，尽管相对有氧运动量[最大摄氧量（Vo₂max）/千克百分比]更大。
20名成年女性自愿参与，其中10名肥胖女性（体重指数[BMI]=34.1±3.2千克/平方米），10名体重正常女性（BMI=20.4±2.1千克/平方米）。为了确定代谢率以及每单位距离的能量消耗与速度的关系，我们在受试者以六种速度（0.50、0.75、1.0、1.25、1.5和1.75米/秒）在跑步机上行走时测量了Vo₂和VCO₂（每次试验5分钟，试验之间有5分钟休息时间）。我们在一段50米长的水平人行道上测量了偏好步行速度，并使用改良的巴尔克跑步机方案测量了Vo₂max。
肥胖受试者步行的成本高出11%，但她们偏好的步行速度与体重正常的受试者相似（分别为1.40米/秒和1.47米/秒，p=0.07）。两组都偏好能使每单位距离的总能量消耗几乎最小化的步行速度。肥胖受试者的Vo₂max/千克较小，因此在偏好速度下她们需要更大的相对有氧运动量（分别为51%和36%，p=0.001）。
肥胖女性偏好能使每单位距离能量消耗最小化的步行速度，尽管这种策略比走得更慢需要更大的相对有氧运动量。我们的结果表明，对于肥胖成年人的体重管理处方而言，在设定距离内走得更慢可能是一项合适的运动建议。
