WORK EFFICIENCY IN LACTATING WOMEN

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 对于人类女性来说，哺乳是生殖过程中最耗能的阶段；这相当于比非怀孕的非哺乳水平增加了大约30%的能量需求。尽管人们一直假设女性将通过增加食物摄入量和/或调动怀孕期间积累的体脂来满足这种增加的能量需求，但实证研究未能证明预期的食物摄入量和体脂储备的利用增加。这促使研究人员研究了第三种选择，即减少能源消耗。本研究的目的是通过研究哺乳期对能量消耗的一项指标--运动能量效率的影响，来加深我们对哺乳期能量消耗的理解。具体地说，我们假设运动中的能量效率在哺乳期比哺乳期后更高。为了验证这一假设，我们将测量39名哺乳期妇女在哺乳高峰期(产后2-3个月)和完全停止母乳喂养两个月后进行纯母乳喂养的锻炼能量效率。在哺乳高峰期和哺乳后期，能量效率将在5-7天内的两天内用相同的自行车功率计进行分级运动测试。我们希望发现哺乳期女性在运动中更有效地利用能量，他的发现将有助于解释她们如何满足哺乳期的能量需求。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. For human females lactation is the most energy-demanding phase of reproduction; it amounts to an increase in energy needs of approximately 30% above non-pregnant non-lactating levels. Although the assumption has been that women will meet this increase in energy need by increasing food intake and/or mobilizing body fat accrued in pregnancy, empirical studies have failed to demonstrate the increases in food intake and utilization of body fat stores expected. This has prompted researchers to examine a third option, i.e. reductions in energy expenditure. The purpose of this study is to improve our understanding of the energy expenditure in lactation by examining the effect of lactation on one measure of energy expenditure, energetic efficiency in exercise. Specifically, we hypothesize that energetic efficiency in exercise is higher in the lactating than the post- lactating state. To test this hypothesis we will measure energetic efficiency in exercise in a sample of 39 lactating women practicing exclusive breastfeeding at peak lactation (2-3 months postpartum) and two months after breastfeeding has ceased completely. At both peak lactation and post-lactation, energetic efficiency will be measured on two non-consecutive days within a 5-7 day period using an identical graded exercise test on a cycle ergometer. We expect to find that lactating women use energy more efficiently in exercise, and that his finding will help explain how they meet the energy demands of lactation.