Given the heightened cardiovascular disease (CVD) risk in post-menopausal women, studies are needed to explore novel, feasible methods for reducing risk in this population. Based on prior data, primarily in other populations, progressive resistance training is a promising candidate. This project will test the effectiveness of a practical, progressive resistance training regimen for lowering numerous CVD risk factors compared to both aerobic training and no exercise in post-menopausal women.
The number of women living with cardiovascular disease (CVD) is greater than for men and CVD is the leading cause of death for women. Post-menopausal women are a particularly vulnerable population in terms of adverse cardiovascular indicators and outcomes. Specifically, they exhibit greater visceral adipose tissue, fasting and postprandial glucose, total cholesterol (Total-C), fasting insulin, and systolic blood pressure, and are at increased risk for coronary heart disease compared to pre-menopausal women. There is also evidence that cardiovascular indicators (i.e., triglycerides, low high-density lipoprotein cholesterol (HDL-C), etc) are stronger risk predictors in women than men. Despite the staggering rates of CVD in post-menopausal women, as noted by the American Heart Association (AHA), CVD remains understudied in this population. Numerous studies have demonstrated the cardioprotective effects of exercise. However, these studies have largely featured younger individuals, primarily men, undergoing aerobic exercise training. Findings in recent years have indicated the potential benefits of resistance training beyond improving muscular size or strength, such as improved aerobic fitness, central adiposity, glycemic control, and cholesterol profiles. However, large clinical gaps have been noted for women with regard to the effects of resistance training on cardiovascular health. Thus, there is a clear need to assess the cardioprotective effects of progressive exercise training in post-menopausal women. SPECIFIC AIMS: 1. To test the hypothesis that realistic full-body progressive resistance training improves markers of (a) cardiovascular health and (b) body composition and muscular health in post-menopausal women versus a low physical-activity control. A. The primary markers of cardiovascular health to be assessed are aerobic capacity, fasting and postprandial metabolic and inflammatory responses, vascular function via flow-mediated dilation (FMD) and markers of angiogenesis. B. The primary body composition and muscle function variables to be assessed are muscle size, isometric and dynamic muscle strength, lean body mass, percent body fat, and abdominal adiposity. 2. To compare the effects of realistic, full-body progressive resistance training in post-menopausal women versus moderate-intensity aerobic exercise, the standard exercise prescription for cardiovascular health, on the cardiovascular, body composition, and muscular health outcomes listed above in 1A. and B.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
68
Women assigned to the resistance exercise training group will complete progressive, full-body resistance exercise 3 times per week for 16 weeks.
Women assigned to the aerobic exercise training group will complete progressive, aerobic exercise 5 times per week for 16 weeks. The aerobic training will progress first in duration, and then in intensity.
192 Colvin Recreation Center
Stillwater, Oklahoma, United States
Change in Aerobic Capacity
Participants will complete a maximal aerobic capacity test to determine VO2peak. The results of this test will be used to determine exercise intensity of the AT training condition, as well as serve as a primary end-point from pre- to post-intervention. In brief, participants will start the test at 25 W pedaling between 60-80 rpm, and the workload will be increased by 25 W each minute thereafter. Participants will exercise until they reach volitional fatigue, and can no longer maintain a pedal cadence greater than 60 rpm for 5 consecutive revolutions. Expired gases will be measured throughout the exercise testing via a metabolic cart and heart rate will be assessed using a wireless system.
Time frame: A week 0 and immediately after the 16-week intervention period
Change in Metabolic and Inflammatory responses to a Meal Tolerance Test (MTT)
Participants will arrive in the laboratory following a 10 h overnight fast and having abstained from exercise for 48 h. An indwelling 24-gauge safelet catheter (Exel International; Redondo Beach, CA) will be inserted into a forearm vein by a phlebotomist (Dr. Emerson), and a slow infusion (\~1 drip/s) of 0.9% NaCl solution will be initiated. A baseline blood draw will be taken to measure fasting metabolic and inflammatory markers. Next, participants will consume a HFM consisting of pie that is 63% fat, 34% carbohydrate, and 3% protein. The amount of pie consumed by each participant is based on body mass (12 kcal/kg). Participants will eat the same HFM pre- and post-intervention. Blood draws will be taken each hour for 6 h post-HFM to characterize the metabolic (TG, glucose, Total-C, HDL-C, LDL-C) and inflammatory and angiogenic (CRP, IL-6, IL-1β, VEGF-A, and VEGF-C) response.
Time frame: A week 0 and immediately after the 16-week intervention period
Changes in Vascular Function
Flow-mediated dilation, which will be used to evaluate vascular function, will be assessed via Doppler ultrasound (Linear Array L745 and SonoScape A6 Portable Ultrasound Machine; Shenzhen, China) both fasting and 2 and 4 h post-HFM. After resting in a quiet, dark room for 15 minutes, the brachial artery will be scanned longitudinally slightly above the antecubital crease via a 12 MHz probe. A blood pressure cuff will be inflated to 230-250 mmHg on the proximal portion of the upper arm for 5 minutes, then suddenly released to induce hyperemia. Vascular measurements will be repeated 45-60 seconds after cuff deflation to determine FMD, which decreases following a HFM.
Time frame: A week 0 and immediately after the 16-week intervention period
Changes in Body Composition
Height and weight will be measured and body composition assessed pre- and post-intervention using a DEXA scan (Hologic Discovery QDR; Marlborough, MA). Specific outcomes will include percent body fat, lean body mass, and abdominal adiposity.
Time frame: A week 0 and immediately after the 16-week intervention period
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