Circuit Weight Training and Blood Pressure Regulation in Prehypertension

描述（由申请人提供）：循环重量训练是一种特殊类型的阻力训练，包括轻重量和短休息时间，并导致有益的心肺和肌肉骨骼适应。最重要的适应之一似乎是降低动脉压，特别是对于可能处于高血压前期的个体。该项目的总体目标是记录高血压前期年轻人循环重量训练对动脉压和动脉压调节的生理机制。该研究将验证以下假设：循环重量训练降低动脉血压、基线交感神经活动和动脉僵硬度，并增加副交感神经心脏控制和心血管压力反射敏感性，与运动训练时间成正比。为了验证这些假设，以下具体目标将被解决：确定12周循环重量训练计划对1)静息动脉压的影响；2)交感神经活动；3)呼吸性窦性心律失常及心血管压力反射敏感性；4)中央和外周动脉硬度。结合区域计划的具体目标，将为有才华的本科生提供全面的研究经验，他们将担任助理。为了实现这些具体目标，在进行结构化循环重量训练之前、之后、第4周、第8周和第12周，将分别进行以下测试：1)受试者坐着，使用自动血压计从手臂测量血压三次，记录平均收缩压和舒张压；2)受试者仰卧位时，直接使用微神经造影技术测量肌肉交感神经活动，并从肘部静脉抽血评估血浆儿茶酚胺浓度；3)受试者将控制自己的呼吸，每分钟15次。将R-R区间转换到频域，将呼吸性窦性心律失常作为功率谱呼吸频带下的积分面积进行评估。自发气压反射灵敏度将在时域和频域进行评估。动态压力反射敏感性将通过释放Valsalva应变时对动脉压力升高的R-R间隔反应来评估；4)采用双向经皮多普勒超声探头，获取左颈总动脉与左股动脉、左股动脉与足背上动脉之间的脉波速度。脉冲波速将计算为测量点之间的距离除以时间间隔的变化。取颈动脉至股动脉的值作为中心刚度指标，取股动脉至足背上动脉的值作为外周刚度指标。通过非药物手段逆转或控制高血压前期将降低未来的总体卫生保健费用。促进体育活动作为一种生活方式的选择，以降低动脉压，将减少心血管疾病和中风的患病率，这是美国第一和第三大死亡原因。

DESCRIPTION (provided by applicant): Circuit weight training is a specific type of resistance training that incorporates light weights and short rest intervals, and results in beneficial cardiorespiratory and musculoskeletal adaptations. One of the most important adaptations appears to be reduction of arterial pressure, especially for individuals who may be prehypertensive. The overall goal of this project is to document physiological mechanisms modulating arterial pressure and arterial pressure regulation in response to circuit weight training in prehypertensive young adults. The proposed research will test the hypotheses that circuit weight training decreases arterial blood pressure, baseline sympathetic neural activity and arterial stiffness, and increases parasympathetic cardiac control and cardiovagal baroreflex sensitivity in direct proportion to exercise training duration. In order to test these hypotheses, the following specific aims will be addressed: Determine the effects of a 12-week circuit weight training program on 1) resting arterial pressure; 2) sympathetic neural activity; 3) respiratory sinus arrhythmia and cardiovagal baroreflex sensitivity; and 4) central and peripheral arterial stiffness. In conjunction with specific goals of the AREA program, comprehensive research experience will be made available to talented undergraduate students who will serve as assistants. To accomplish these specific aims, the following tests will be performed before, and then after 4, 8, and 12 weeks of structured circuit weight training: 1) with subjects in the seated position, blood pressure will be measured three times from the arm using an automated sphygmomanometer, and the average systolic and diastolic pressures will be recorded; 2) with subjects in the supine position, muscle sympathetic nerve activity will be measured directly using the microneurography technique, and blood will be drawn from an anticubital vein for assessment of plasma catecholamine concentrations; 3) subjects will control their breathing at 15 breaths per minute. R-R intervals will be converted to the frequency domain, and respiratory sinus arrhythmia will be assessed as the integrated area under the respiratory frequency band of the power spectrum. Spontaneous baroreflex sensitivity will be assessed in both time and frequency domains. Dynamic baroreflex sensitivity will be assessed from R-R interval responses to arterial pressure elevations during release from Valsalva strain; 4) Using bidirectional transcutaneous Doppler ultrasound probes, pulse waves velocities between the left common carotid artery and the left femoral artery, and the left femoral artery and the superior dorsalis pedis artery will be obtained. Pulse wave velocity will be calculated as the distance between measuring sites divided by the change in time intervals. Values attained from the carotid to femoral artery will be taken as an index of central stiffness, while values from the femoral to superior dorsalis pedis artery will be taken as an index of peripheral stiffness. Reversing or controlling prehypertension through non-pharmacological means will decrease future overall health care costs. Promoting physical activity as a lifestyle choice to decrease arterial pressure will decrease the prevalence of cardiovascular disease and stroke, which are the first and third leading causes of death in the United States.