THE EFFECTS OF MODERATE- AND HIGH-INTENSITY EXERCISE ON VASCULAR FUNCTION

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。 心血管疾病是一个主要的健康问题，基本上可以通过改变生活方式来预防，比如增加体力活动。尽管我们清楚地知道久坐不动的生活方式带来的风险，但大多数美国人并没有达到推荐的维持心血管健康的体力活动指南。内皮功能障碍被认为是动脉粥样硬化发展过程中的早期事件，其存在和严重程度与未来的心脏发病率和死亡率高度相关。血管内皮细胞对正常刺激的反应不能产生血管扩张剂NO，导致血管张力调节和炎症反应受损。运动训练已被证明对血管内皮细胞功能有有益的影响，无论是对健康的人还是那些风险增加的人或临床诊断为心血管疾病的人。本研究的目的是确定运动强度对瘦肉型和腹型肥胖者FMD急性变化的影响。这项研究将第一次检查单次运动后急性时间进程的FMD测量。我们假设，与中等强度运动相比，30分钟高强度运动后FMD的增加将具有更大的幅度和持续时间，并且这种急性运动效应将在健康体重和肥胖成年人中观察到(但肥胖者可能会减弱)。作为次要目标，将使用多普勒超声和Definity微泡的对比增强来检查高强度运动后立即发生的下肢微血管和大血管变化的时间。这一结果将有助于我们了解运动对血管内皮细胞功能以及全身和微血管血流的影响因素，并可能为心血管疾病高危人群提供更具体的运动处方。

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. Cardiovascular disease is a major health problem that is largely preventable through lifestyle modifications, such as increasing physical activity. Despite our clear understanding of the risks associated with a sedentary lifestyle, most Americans do not meet the recommended physical activity guidelines for maintaining cardiovascular health. Endothelial dysfunction is recognized as an early occurrence in the development of atherosclerosis, and its presence and severity are highly correlated with future cardiac morbidity and mortality. Failure of the vascular endothelium to produce the vasodilator NO in response to normal stimuli results in the impaired regulation of vascular tone and inflammation. Exercise training has been demonstrated to have beneficial effects on endothelial function in studies of both healthy individuals and those with an elevated risk or clinically diagnosed cardiovascular disease. The purpose of the current study is to determine the effect of exercise intensity on the acute changes in FMD in both lean and abdominally obese individuals. This study will be the first to examine the acute time course FMD measurements following a single bout of exercise. We hypothesize that the augmentation of FMD will be of greater magnitude and duration following 30 minutes of high-intensity compared with moderate-intensity exercise, and that this acute exercise effect will be observed in both healthy weight and obese adults (but may be attenuated in the obese). As a secondary aim, the timing of microvascular and macrovascular changes in the lower limb immediately following high-intensity exercise will be examined using Doppler ultrasound and contrast enhancement with Definity microbubbles. The results will contribute to our understanding of the factors involved in the effects of exercise on endothelial function, and systemic and microvascular blood flow, and may lead to more specific exercise prescription for those at risk for CVD.