Influence of the Autonomic Nervous System on Endothelial Function as an Acute Response to Exercise in Hypertensive Individuals: a Randomized Double-blind Protocol Study
试验速览
- 阶段
- 不适用
- 发起方
- 入组人数
- 39
- 试验地点
- 1
- 主要终点
- Changes in the endothelial function of hypertensive individuals after a session of aerobic exercise, resistance exercise and combined exercise in α1-adrenoreceptor blocker and placebo condition.
研究概览
简要总结
Systemic arterial hypertension (SAH) has a direct association with endothelial dysfunction and major cardiovascular events. Evidence points to possible benefits of aerobic training in the endothelial function analyzed by the flow mediated dilation technique (flow mediated dilatation - FMD) in individuals with SAH. However, little is known about the influence of the autonomic nervous system (ANS) on the results of brachial artery FMD after different types of acute exercise in individuals with SAH. Thus, the objective of the research is to analyze the influence of the ANS on the FMD of the brachial artery of individuals with SAH after a session of aerobic (EA), resistance (ER) and combined (EC) exercise. For this, thirty-nine hypertensive individuals aged 35 to 55 years will be recruited and will be randomized to 2 sessions of AS, ER or EC. Also, within each modality, they will be randomized to α1-adrenergic block (Doxazosin 0.05 mg / kg-1) or placebo. The FMD will be performed by ultrasound 10 minutes before, as well as 10, 40 and 70 minutes after the exercise sessions and the autonomic control will be monitored (Finometer) for 10 minutes before each FMD. Arterial stiffness will also be analyzed, using the pulse wave velocity (PWV) by the Complior Analyzer. It is expected to demonstrate with this research the influence of the ANS on the FMD of the brachial artery in individuals with SAH in different physical exercises. This knowledge contributes to a better training prescription in this population.
详细描述
INTRODUCTION
Endothelial dysfunction precedes atherosclerosis. Endothelial cells play an important role in the modulation of vascular angiogenesis, inflammatory responses, homeostasis, as well as vascular tone and permeability. This vascular protection function is largely attributed to nitric oxide synthase endothelial, an enzyme responsible for the production of nitric oxide (NO).
The decrease in local NO bioavailability and/or insufficient vasomotor response characterizes endothelial dysfunction; a fact evidenced in situations such as SAH, diabetes mellitus, obesity, dyslipidemia, menopause and sedentary lifestyle. The evaluation of flow-mediated dilation (FMD) of the brachial artery, although it is an indirect method to assess endothelial function, is not invasive and a large part of its result depends on NO. The findings resulting from the acute stimulus of physical exercise can also predict long-term adaptations, therefore, it has been widely used.
Within this scenario, the change in lifestyle, including regular physical exercise, is part of the recommendations of antihypertensive therapy. The most cited factors, responsible for the potential antihypertensive effect and better endothelial response to long-term exercise include reduced sympathetic activity, balance between vasodilator and vasoconstrictor factors and reduced levels of vasoconstrictor endothelin-1.
Analyzes of a resistance exercise session in the FMD demonstrated that the knee extension exercise performed with moderate intensity, as well as, with light intensity can reduce the FMD 10-30-60 minutes after the session in individuals healthy. Interestingly, the same session, when performed at high intensity, was not able to provide changes in the FMD, leading to the idea of an inverse relationship between intensity of resistance exercise and FMD response. Recently, the investigators demonstrated that an aerobic exercise session, resisted and combined (resisted and aerobic) performed in moderate intensity for 40 minutes and exclusively with lower limbs, were not able to alter the FMD of the brachial artery of individuals with SAH when analyzed 10-40-70 minutes after the sessions. These results were accompanied by maintenance of endothelial microvesicle levels and factors involved with oxidative stress. Collectively, the investigators can raise the hypothesis that other factors, such as exacerbation of sympathetic activity in untrained members, may cause vasoconstriction and redirect blood flow to trained members, consequently, competing with endothelium-dependent vasodilating activity.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- Double (Participant, Investigator)
盲法说明
The allocation secrecy will be maintained until the time of the experiments, through a randomization list, in a remote place and without direct access by the researchers.
入排标准
- 年龄范围
- 35 Years 至 55 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Clinical diagnosis of systemic arterial hypertension;
- •Must be able to reality physical exercise.
排除标准
- •Diabetes mellitus;
- •Chronic renal failure;
- •Body mass index ≥ 35kg/m2;
- •Coronary artery disease;
- •Heart failure;
- •Use of beta-blocker;
- •Uso of alpha-blocker;
- •Menopause (woman).
研究组 & 干预措施
Aerobic exercise session
The aerobic exercise session will be performed on a horizontal cycle ergometer. A warm-up will be performed (5 minutes), followed by 40 minutes with moderate intensity (60% HRreserve) and controlled by a heart rate monitor, as well as the subjective effort scale (Borg 6 to 20 points). Blood pressure, heart rate and the Borg scale will be assessed at the beginning of aerobic exercise and every 5 minutes until the end.
干预措施: α1-adrenergic block (Drug)
Aerobic exercise session
The aerobic exercise session will be performed on a horizontal cycle ergometer. A warm-up will be performed (5 minutes), followed by 40 minutes with moderate intensity (60% HRreserve) and controlled by a heart rate monitor, as well as the subjective effort scale (Borg 6 to 20 points). Blood pressure, heart rate and the Borg scale will be assessed at the beginning of aerobic exercise and every 5 minutes until the end.
干预措施: Placebo (Other)
Resistance exercise session
The resistance exercise session will be structured with knee extension, knee flexion, leg pressure and plantar flexion, in a station with guided weights, with 4x12 repetitions and 60% intensity of 1-RM; the cadence will be adjusted to 2:2 (concentric: eccentric) and controlled by a metronome. The rest between sets and exercises will be 90 seconds (total duration: 40 minutes). Blood pressure, heart rate and Borg scale will be recorded at the beginning and at the end of the 4th series of each exercise.
干预措施: α1-adrenergic block (Drug)
Resistance exercise session
The resistance exercise session will be structured with knee extension, knee flexion, leg pressure and plantar flexion, in a station with guided weights, with 4x12 repetitions and 60% intensity of 1-RM; the cadence will be adjusted to 2:2 (concentric: eccentric) and controlled by a metronome. The rest between sets and exercises will be 90 seconds (total duration: 40 minutes). Blood pressure, heart rate and Borg scale will be recorded at the beginning and at the end of the 4th series of each exercise.
干预措施: Placebo (Other)
Combined exercise session
The combined exercise session will be structured with 20 minutes of resistance exercise + 20 minutes of aerobic exercise, as already described, except that the resistance exercises will have 2 sets of each exercise. As with other sessions, blood pressure, heart rate and the Borg scale will be assessed at the beginning and end of the second series of resistance exercise, as well as at the beginning and every 5 minutes of aerobic exercise up to 15 minutes after end of exercises.
干预措施: α1-adrenergic block (Drug)
Combined exercise session
The combined exercise session will be structured with 20 minutes of resistance exercise + 20 minutes of aerobic exercise, as already described, except that the resistance exercises will have 2 sets of each exercise. As with other sessions, blood pressure, heart rate and the Borg scale will be assessed at the beginning and end of the second series of resistance exercise, as well as at the beginning and every 5 minutes of aerobic exercise up to 15 minutes after end of exercises.
干预措施: Placebo (Other)
结局指标
主要结局
Changes in the endothelial function of hypertensive individuals after a session of aerobic exercise, resistance exercise and combined exercise in α1-adrenoreceptor blocker and placebo condition.
时间窗: Ten minutes before the exercise session and 10, 40 and 70 minutes after the exercise session.
The method of assessing the flow-mediated dilation (FMD) of the brachial artery by ultrasonography is an indirect method to assess endothelial function. To analyze the FMD of the brachial artery a rapid deflation cuff will be placed around the forearm 5 cm distal to the antecubital fossa and the image of the brachial artery will be obtained in the distal third of the arm. Baseline diameters will be recorded for 1 minute, before the forearm cuff is inflated at 50 mmHg above the SBP, for 5 minutes. The recording of the images will be resumed 30 seconds before the deflation of the cuff and maintained for 3 minutes after deflation. The video signal of the Doppler Ultrasound will be recorded in real time by a USB video card and saved for offline analysis. The analysis of diameter will be performed using edge detection and wall tracking software. The FMD will be calculated as the percentage change in the peak diameter after deflating the cuff from the baseline diameter.
次要结局
未报告次要终点