Speakman J R
Department of Zoology, University of Aberdeen, Scotland, United Kingdom.
Am J Clin Nutr. 1998 Oct;68(4):932S-938S. doi: 10.1093/ajcn/68.4.932S.
Scientists have been measuring energy expenditure by using gas exchange for the past 200 y. This technique is based on earlier work in the 1660s. Gas exchange in respirometers provides accurate and repeatable measures of resting metabolic rate. However, it is impossible to duplicate in a respirometry chamber the diversity of human behaviors that influence energy expenditure. The doubly labeled water technique is an isotope-based method that measures the energy expenditure of unencumbered subjects from the divergence in enrichments of 2 isotopic labels in body water--1 of hydrogen and 1 of oxygen. The method was invented in the 1950s and applied to small animals only until the early 1980s, mostly because of the expense. Since 1982, when the first study in humans was published, its use has expanded enormously. Although there is some debate over the precise calculation protocols that should be used, the differences between alternative calculations result in relatively minor effects on total energy expenditure estimates (approximately 6%). Validation studies show that for groups of subjects the method works well, but that precision is still relatively poor (8-9%) and consequently the method is not yet sufficiently refined to provide estimates of individual energy expenditures.
在过去的200年里，科学家们一直在使用气体交换法来测量能量消耗。这项技术基于17世纪60年代的早期研究。呼吸计中的气体交换能提供静息代谢率的准确且可重复的测量值。然而，在呼吸测量室中不可能复制出影响能量消耗的人类行为的多样性。双标水技术是一种基于同位素的方法，它通过测量体内水中两种同位素标记（一种是氢，一种是氧）的富集度差异来测量无拘束受试者的能量消耗。该方法发明于20世纪50年代，直到20世纪80年代初才仅应用于小动物，主要是因为费用问题。自1982年发表了第一项关于人类的研究以来，其应用范围大幅扩大。尽管对于应使用的精确计算方案存在一些争议，但不同计算方法之间的差异对总能量消耗估计值的影响相对较小（约6%）。验证研究表明，对于受试者群体而言该方法效果良好，但精度仍然相对较差（8 - 9%），因此该方法尚未得到充分完善，无法提供个体能量消耗的估计值。
