SYMPATHETIC VASOCONSTRICTOR RESPONSIVE DURING SMALL MUSCLE EXERCISE AGE &SEX

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。这项研究的目的是确定年轻和老年受试者在锻炼肌肉时的交感反应性是否存在差异。据推测，在腿部运动中，通过腿部血管传导对缺血握力(交感刺激)的反应，年龄较大的受试者将比年轻受试者具有更大的交感血管收缩反应性。在这项研究中，共有78名健康受试者将被研究。共有100名受试者被要求参加招聘，以说明辍学的原因。研究对象将被分成6组，每组13人，包括20岁至30岁的男性和女性未经培训的对象，以及60岁至75岁的受过培训和未受培训的男性和女性。这项研究需要对每个科目进行三次GCRC访问。最初的筛查访问将用于管理用于纳入和排除标准的测试，并确定运动健康水平。第一次实验访问将获得关于腿部血流量的重复性数据，以及用于为后续研究建立运动目标点的最大握力和腿部伸展力量。在第二次实验访问中，受试者将以10W的速度进行非优势腿部伸展运动。6分钟后，将有4分钟的时间，在此期间，受试者将以60%的最大力量进行静态缺血性握手练习。然后，受试者将停止握手练习，同时继续腿部练习。两条腿的血流量将在整个练习方案中进行测量。然后重复这个方案，进行更高水平的腿部锻炼(30瓦)。

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. The purpose of this study is to determine whether there are differences in sympathetic responsiveness in exercising muscles in younger and older subjects. It is hypothesized that older subjects will have greater sympathetic vasoconstrictor responsiveness than younger subjects, as evaluated by changes in leg vascular conductance in response to ischemic handgrip (sympathetic stimulus) during leg exercise. For this study a total of 78 healthy subjects will be studied. A total of 100 subjects are requested for recruitment to account for dropouts. Subjects will be stratified into 6 groups of 13 individuals consisting of male and female untrained subjects age 20 to 30 years, and trained and untrained men and women 60 to 75 years of age. The study entails three visits to the GCRC for each subject. An initial screening visit will be used to administer tests used for inclusion and exclusion criteria and to determine level of exercise fitness. The first experimental visit will obtain reproducibility data on leg blood flow, and maximal handgrip and leg extension force production used to establish exercise target points for the subsequent study. During the second experimental visit subjects will perform non-dominant leg extension exercise at 10 watts. After 6-minutes there will a 4-minute period during which the subject will perform static ischemic handgrip exercise at 60% maximal force. The subjects will then cease the handgrip exercise while continuing leg exercise. Blood flow in both legs will be measured throughout the exercise protocol. The protocol will then be repeated with a higher level of leg exercise (30 watts).