Measuring the Energy of Ventilation and Circulation during Human Walking using Induced Hypoxia
Measuring the Energy of Ventilation and Circulation during Human Walking using Induced Hypoxia
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DOI：
10.1038/s41598-017-05068-8
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发表时间：
2017-07-10
影响因子：
4.6
通讯作者：
Pontzer, Herman
中科院分区：
文献类型：
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作者：
Horiuchi, Masahiro;Fukuoka, Yoshiyuki;Pontzer, Herman
步行过程中的能量消耗(EE)包括运动和支撑身体以及呼吸和循环的能量成本。我们测量了在三种不同氧气浓度下步行时的EE。11名健康、年轻的男性高原居民，在常压常氧(21%O-2)、中度低氧(15%O-2)和重度低氧(11%O-2)条件下，以7种步速(0.6 7~1.83m S(-1))在跑步机上水平坡度行走。通过比较低氧引起的心率(HR[bpm])、通气量(V-E[L分钟(-1)])和每个速度下能量消耗(EE[W])的变化，我们能够确定循环和呼吸成本。在结合HR和VE的多因素模型中，VE每增加L分钟呼吸成本为0.44+/-0.15W，每增加HR循环成本为0.24+/-0.05W(模型调整r(2)=0.97p<；0.001)。这些VE成本大大低于之前忽略HR对心肺工作的贡献的研究。估计的人力资源成本与导管术研究得出的指标一致，但略高于这些指标。心肺成本占静息EE的23%，但不到净步行成本的5%(即减去静息EE)。
Energy expenditure (EE) during walking includes energy costs to move and support the body and for respiration and circulation. We measured EE during walking under three different oxygen concentrations. Eleven healthy, young, male lowlanders walked on a treadmill at seven gait speeds (0.67-1.83 m s(-1)) on a level gradient under normobaric normoxia (room air, 21% O-2), moderate hypoxia (15% O-2), and severe hypoxia (11% O-2). By comparing the hypoxia-induced elevation in heart rate (HR [bpm]), ventilation (V-E [L min(-1)]) with the change in energy expenditure (EE [W]) at each speed, we were able to determine circulatory and respiratory costs. In a multivariate model combining HR and VE, respiratory costs were 0.44 +/- 0.15 W per each L min(-1) increase in VE, and circulatory costs were 0.24 +/- 0.05 W per each bpm increase in HR (model adjusted r(2) = 0.97, p < 0.001). These VE costs were substantially lower than previous studies that ignored the contribution of HR to cardiopulmonary work. Estimated HR costs were consistent with, although somewhat higher than, measures derived from catheterization studies. Cardiopulmonary costs accounted for 23% of resting EE, but less than 5% of net walking costs (i.e., with resting EE subtracted).