Comparison of the Cardiovascular Benefits of Resistance, Aerobic, and Combined Exercise

Study Overview
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Brief Summary
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As the leading cause of death, cardiovascular disease (CVD) accounts for about one-third of U.S. mortality. Physical inactivity, one of the main CVD risk factors, causes 6% of coronary heart disease worldwide. The American Heart Association has identified cardiovascular health behaviors including smoking, obesity, diet, and aerobic exercise; however, resistance exercise was not included due to the limited evidence of its efficacy. Comparatively, the cardiovascular benefits of aerobic training have been well-documented whereas the independent and additive benefits of resistance training on cardiovascular health have not been established. Thus, this project is aimed to answer one of the most common questions about exercise and health:What type or combination of exercise is most effective for CVD prevention? This project will significantly contribute to developing more effective CVD prevention approaches, advancing more comprehensive physical activity guidelines, and providing important insights and novel opportunities for the future science of physical activity and health.

Detailed Description
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Participants will be randomly assigned to aerobic exercise, resistance exercise, combined aerobic and resistance exercise, or a no exercise control group for 1 year. Participants in all four groups will receive healthy diet and lifestyle education sessions and will track their daily steps, body weights, and food intake throughout the 1-year intervention. They will also complete baseline, 6-month, and 12-month physical examinations, which will include assessments of blood pressure, blood lipids, body composition, and aerobic and muscular fitness.

Official Title
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Comparison of the Cardiovascular Benefits of Resistance, Aerobic, and Combined Exercise

Conditions
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Cardiovascular Diseases

Intervention / Treatment
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* Behavioral: aerobic exercise
* Behavioral: resistance exercise
* Behavioral: Combined resistance and aerobic exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Non-smoker Systolic/diastolic blood pressure of 120-139/80-89 mmHg (without taking any anti-hypertensive medication) Overweight or obese: body mass index of 25-40 kg/m2; Asian 23-40 kg/m2 Inactive: less than 150 min/week of exercise over the past 3 months Capable of performing the required exercise training Exclusion Criteria: Unstable coronary heart disease or heart failure Uncontrolled arrhythmias or severe aortic stenosis Acute myocarditis, endocarditis, or pericarditis Cancer, requiring treatment in the past 5 years Autoimmune diseases, affecting the immune system Plans to be away/travel for greater than 4 weeks in the next year Pregnancy/anticipated pregnancy during the study Other medical condition that is life-threatening or can interfere with or be aggravated by the exercise training

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Aerobic exercise (AE)<br>AE training will consist of 60 min of treadmill, elliptical, or bike exercise at a moderate to vigorous intensity (50-80% of heart rate reserve). Intensity of the exercise sessions will be built up gradually. Sessions will occur 3 times per week for the duration of the 1 year trial. | Behavioral: aerobic exercise<br>* AE training will consist of 60 min of treadmill, elliptical, or bike exercise at a moderate to vigorous intensity (50-80% of heart rate reserve). Intensity of the exercise sessions will be built up gradually. Sessions will occur 3 times per week for the duration of the 1 year trial.<br>|
| Experimental: Resistance exercise (RE)<br>RE will consist of 3 sets of 8-15 repetitions at 50-80% of 1 rep-max of each exercise for 12 exercises (chest press, shoulder press, pull-down, back extension, abdominal crunch, torso rotation, biceps curl, triceps extension, leg press, leg extension, leg curl, and calf raise). Weight loads will be increased gradually. With one minute of rest between sets, this plan is estimated to take approximately 60 minutes per session. Sessions will occur 3 times per week for the duration of the 1 year trial. | Behavioral: resistance exercise<br>* RE will consist of 3 sets of 8-15 repetitions at 50-80% of 1 rep-max of each exercise for 12 exercises (chest press, shoulder press, pull-down, back extension, abdominal crunch, torso rotation, biceps curl, triceps extension, leg press, leg extension, leg curl, and calf raise). Weight loads will be increased gradually. With one minute of rest between sets, this plan is estimated to take approximately 60 minutes per session. Sessions will occur 3 times per week for the duration of the 1 year trial<br>|
| Experimental: Combined Resistance and Aerobic Exercise<br>Participants will perform exactly the same AE and RE exercises as listed previously; however, the time of AE and RE will each be reduced to 30 min (for 60 min/session total). For the RE aspect, participants will perform 2 sets of 8-15 repetitions of 9 exercises (excluding biceps curl, triceps extension, and calf raise, as these are minor muscle groups). Exercise intensity and resistance will be increased gradually. Combined AE and RE sessions will take place 3 times per week for the duration of the trial. | Behavioral: Combined resistance and aerobic exercise<br>* Participants will perform exactly the same AE and RE exercises as listed previously; however, the time of AE and RE will each be reduced to 30 min (for 60 min/session total). For the RE aspect, participants will perform 2 sets of 8-15 repetitions of 9 exercises (excluding biceps curl, triceps extension, and calf raise, as these are minor muscle groups). Exercise intensity and resistance will be increased gradually. Combined AE and RE sessions will take place 3 times per week for the duration of the trial.<br>|
| No Intervention: No training control<br>Participants in this group will be asked to maintain their current level of activity during the 1 year study period. After 1 year, they will be offered the training program of their choice (AE, RE, or combined). | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in composite cardiovascular disease risk score (z-score) | The primary outcome is the change from baseline in the composite cardiovascular disease risk score (z-score) calculated using resting blood pressure, low-density lipoprotein cholesterol, fasting glucose, and percent body fat. Each risk factor will be individually standardized and expressed as sex-specific z-score by using the formula = (value - mean)/standard deviation for each participant. | 12 months |