The purpose of this study is to determine the effect of high-intensity interval training (HIIT) in comparison to moderate-intensity continuous training (MCT) on blood pressure, blood vessel function, and blood pressure reactivity.
It is estimated that one-third of the adult population in the United States has blood pressure values that are classified as prehypertension. This slight elevation in blood pressure has been shown to result in an increased risk for developing hypertension and cardiovascular disease. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) recommends lifestyle modifications for individuals classified as prehypertensive. One lifestyle modification suggested by JNC7 is regular physical activity. Aerobic exercise, like moderate-intensity continuous training (MCT), has been shown to improve blood pressure, blood vessel function, and arterial stiffness in those with prehypertension. However, a major barrier to exercise adherence is the time commitment required. High-Intensity Interval Training (HIIT), which requires individuals to work at higher intensities for shorter durations, may offer an alternative training design that would reduce the time commitment. Previous studies have shown HIIT to be equal to or better at improving cardiorespiratory fitness and blood vessel function in multiple populations. Limited information is present on HIIT training in those with prehypertension. In this study, participants will be randomized into one of the two training program designs mentioned above (MCT or HIIT). Both programs will be completed over an 8-week period (3 sessions per week) and each training session will be supervised. Participants will complete testing visits before and after the training program to collect measures of cardiovascular health (exercise capacity, blood pressure, blood vessel function, and blood pressure reactivity). The goal is to compare the effects of the training programs on these measures of cardiovascular health.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
20
Supervised exercise sessions will be performed on a upright cycle ergometer. Training sessions involve 20 minutes of exercise by completing 10 repetitions of 60 seconds of exercise at 90-95% maximal heart rate with 60 seconds of active rest between each repetition at 50-60% maximal heart rate.
Supervised exercise sessions will be performed on a upright cycle ergometer. Training sessions involve 30 minutes of continuous exercise at 65-70% maximal heart rate.
Department of Kinesiology and Applied Physiology, University of Delaware
Newark, Delaware, United States
Blood Pressure
Resting blood pressures measuring by automated oscillometric device
Time frame: Change from baseline resting blood pressure at 8 weeks
Peak Aerobic Capacity
Peak oxygen uptake (VO2peak/max) during incremental cycling exercise until exhaustion
Time frame: Change from baseline VO2peak at 8 weeks
24-Hour Ambulatory Blood Pressure
24 hours of continuous ambulatory blood pressure monitoring by oscillometric device
Time frame: Change from baseline 24-hour ambulatory blood pressure at 8 weeks
Pulse Wave Analysis
Central blood pressure measures assessed by radial tonometry
Time frame: Change from baseline central blood pressure measures at 8 weeks
Endothelial Function
Assessed by brachial artery flow mediated dilation and change in blood in femoral artery in response to passive limb movement
Time frame: Change from baseline endothelial function at 8 weeks
Arterial stiffness
Pulse wave velocity measures (carotid to femoral and femoral to distal) assessed by applanation tonometry
Time frame: Change from baseline pulse wave velocity measures at 8 weeks
Blood Pressure Reactivity
Blood pressure response to graded exercise test and handgrip exercise
Time frame: Change from baseline blood pressure reactivity at 8 weeks
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