EFFECTS OF EXERCISE ON LACTATION PERFORMANCE IN HUMANS

产后期间是一个时间，当许多妇女希望减少身体 脂肪，经常建议锻炼作为实现这一目标的一种手段。 然而，人们担心， 身体活跃的女性可能不足以获得最佳母乳 生产 迄今为止，对此还没有系统的研究 问题. 众所周知，哺乳和运动都会影响血浆中 参与碳水化合物、蛋白质和脂质代谢的激素。 虽然增加运动会导致更高的能量需求。 这些荷尔蒙的变化可能会促进乳房更大的效率， 牛奶的合成，从而保护，牛奶生产在面对 高能量消耗。 我们的初步数据比较 运动妇女与哺乳期久坐的妇女显示， 母乳生产的差异，尽管高能量 前一组的支出（3 169千卡/天）。 本研究的目的是：1）评价 为期12周的有氧锻炼计划的效果 每周五次，对母乳量和成分进行检查，以及2） 以确定是否血浆激素水平（催乳素，胰岛素， 皮质醇和T3）通过运动和波动进行修改， 在出生后的头四个月， 哺乳期 实验设计将随机分配哺乳期妇女 a）运动组（N=15），其中 受试者将在产后7周开始锻炼计划，或B） 对照组（N=15），受试者将不进行 在研究期间每周进行一次以上的剧烈运动。 母亲饮食摄入量和活动水平评估（3天 记录），身体组成（流体静力学称重和皮褶）， 静息代谢率（间接量热法），血浆激素 水平，母乳量（3天测试称重），乳汁成分 （24小时采样）和婴儿生长将在基线（6-7 wks）和产后12-13和19-20周。 最大摄氧量 (V02最大值）将在6-7周和19-20周时测量，作为 有氧健身 这项研究的结果将是重要的不仅从 公共卫生政策的立场，而且在理解 母体营养状况之间的代谢相互关系， 体力活动和泌乳表现。

The postpartum period is a time when many women wish to reduce body fat, with exercise often recommended as a means to achieve this. However, concern has been raised that the energy intake of very physically active women may be inadequate for optimal breast milk production. To date, there has been no systematic research on this issue. Both lactation and exercise are known to influence levels of plasma hormones involved in carbohydrate, protein and lipid metabolism. Although increased exercise leads to higher energy requirements. these hormonal changes may promote greater efficiency in breast milk synthesis, thereby, protecting, milk production in the face of high energy expenditure. Our preliminary data comparing exercising women with sedentary women during lactation show no difference in breast milk production, despite a high energy expenditure (3169 kcal/d) in the former group. The objectives of the proposed research are: 1) to evaluate the effect of a 12-week exercise program consisting of aerobic workouts five times per week on breast milk volume and composition, and 2) to determine whether plasma hormone levels (prolactin, insulin, cortisol and T3) are modified by exercise and fluctuations in maternal body composition during the first four months of lactation. The experimental design will be to randomly assign lactating women to one of two groups: a) an exercise group (N=15), in which subjects will begin an exercise program at 7 wks postpartum, or b) a control group (N=15), in which subjects will not undertake vigorous exercise more than once per week during the study. Assessments of maternal dietary intake and activity level (3-day record), body composition (hydrostatic weighing and skinfolds), resting metabolic rate (indirect calorimetry), plasma hormone levels, breast milk volume (3-day test-weighing), milk composition (24-hr sampling) and infant growth will be made at baseline (6-7 wks) and at 12-13 and 19-20 wks postpartum. Maximum oxygen uptake (V02 max) will be measured at 6-7 and 19-20 wks as an indicator of aerobic fitness. The results of this study will be important not only from the standpoint of public health policy but also in understanding the metabolic interrelationships between maternal nutritional status, physical activity, and lactation performance.