BODY FLUID REGULATION IN AGING ADULTS WITH EXERCISE

据报道，老年人长期脱水，尽管 不能维持正常水合的原因还不清楚。 脱水导致循环和体温调节障碍， 特别是在体力活动或高温暴露期间，并使 心血管和热相关疾病风险增加的个体 损伤 本项目的总体假设是： A.老年人相对脱水的部分原因是 身体不活动，是由于涉及的系统的去适应， 维持细胞外液量。 B.身体活动计划将导致体液的改善 调节，从而恢复循环和体温调节潜力。 该项目的第一个目标是确定 老年人的慢性脱水，并确定这些是如何 通过增加体力活动来逆转。 我们会补充水分 老年人，以确定在调节电路的赤字的网站。 我们将在耐力训练过程中重复这些研究 程序. 第二个目的是检验以下假设：a）低血容量 限制了老年人在身体活动中调节体温的能力， 活动或热暴露和B）增加的身体活动诱导 血容量扩张，从而提高体温调节能力 在标准运动/加热协议期间。 目前尚不清楚， 人们保持了扩大血容量的能力。 第三个目的是表征心肺（CP）压力感受性反射 老年人在训练计划之前和期间的敏感性。 CP 压力反射敏感性影响动脉血压调节; 因此，CP压力感受性反射敏感性的变化可能参与了 随着年龄的增长逐渐受损。 CP压力反射敏感性也影响 体液平衡;高敏感性，与不健康有关 个体，将导致较低的血容量。 我们将测试 假设老年人具有较高的CP压力反射敏感性， 不适合年轻人，CP压力反射敏感性会降低 随着健身的增加。 通过确定与慢性脱水相关的机制， 不活跃的老年人，以及在多大程度上可以改变这些与 活动;并通过确定是否血液容量的能力 随着年龄的增长，扩张及其相关的好处得以保留; 并通过确定CP压力感受性反射是否随年龄或 活动，我们希望提供深入了解相关的机制， 随着年龄的增长，功能下降，以及功能的改善是如何 由活动增加引起的。

Older people are reported to be chronically dehydrated, although the cause of the inability to maintain euhydration is not well understood. Dehydration results in circulatory and thermoregulatory impairments, particularly during physical activity or heat exposure, and places the individual at an increased risk of cardiovascular and heat-related injury. The overall hypotheses of this project are: A. The relative dehydration in older people is in part the consequence of physical inactivity and is due to deadaptation of the systems involved in maintenance of extracellular fluid volume. B.A physical activity program will result in improvements in body fluid regulation, and thus restore circulatory and thermoregulatory potential. The first aim of the project is to determine the reason(s) for the chronic dehydration in older people and to determine how these are reversed by increased physical activity. We will dehydrate and rehydrate older people to determine the site of deficit in the regulatory circuit. We will repeat the studies during the course of an endurance training program. The second aim is to test the hypotheses that a) a low blood volume restricts the ability of older people to thermoregulate during physical activity or heat exposure and b) increased physical activity induces blood volume expansion, thus improving the ability to thermoregulate during a standard exercise/heat protocol. It is not known whether older people retain the ability to expand blood volume. The third aim is to characterize cardiopulmonary (CP) baroreflex sensitivity in older people before and during a training program. CP baroreflex sensitivity affects arterial blood pressure regulation; therefore, changes in CP baroreflex sensitivity may be involved in the progressive impairment with age. CP baroreflex sensitivity also affects body fluid balance; a high sensitivity, associated with unfit individuals, will result in a lower blood volume. We will test the hypothesis that older people have a high CP baroreflex sensitivity, as do unfit younger people, and that CP baroreflex sensitivity will decrease with increasing fitness. By determining the mechanisms associated with the chronic dehydration in inactive older people and the extent to which these can be changed with activity; and by determining whether the capability for blood volume expansion, and its associated benefits, is retained with advancing age; and by determining whether CP baroreflexes are altered with age or with activity, we hope to provide insight into the mechanisms associated with reductions in function with aging and how improvements in function are induced by increased activity.