Exercise Dose-Response Effects in Prediabetes

Study Overview
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Brief Summary
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The purpose of the study is to evaluate the effects of different amounts and intensities of aerobic exercise training programs, with and without weight loss, in people who are at risk for diabetes. An additional purpose of the study is to evaluate the factors in the blood and in exercising muscles that contribute to the improvement in those risk factors. This information will be used to improve exercise training guidelines for improving cardiovascular and metabolic health in people with abnormal fasting glucose, also known as prediabetes.

Detailed Description
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729 subjects were consented, 288 participants were randomized.

Official Title
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Exercise Dose-Response Effects in Prediabetes: Responses and Mechanisms

Conditions
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Pre-Diabetes

Intervention / Treatment
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* Behavioral: Aerobic Exercise
* Behavioral: Aerobic Exercise
* Behavioral: Aerobic Exercise
* Behavioral: Exercise and Diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age: 45-75 years Moderately Overweight determined by Body Mass Index: 25.0 - 35.4 Fasting plasma glucose: > 95 - < 126 mg/dL until 2/15/2012 when lower limit was adjusted to > 100 mg/dL o Readings from two separate days, both being > 95 (> 100 after 2/15/2012)and one of the two being < 126 Low density (LDL) cholesterol: < 190 mg/dL Triglycerides: < 600 mg/dL Resting blood pressure: < 160/90 mmHg Inactive: Exercise < one day/week; Peak oxygen consumption: > 18.0 - < 40.0 ml/kg/min until 2/15/2012 when lower limit was adjusted to 12.0 ml/kg/min Medications: Stable use of all medications for > three months Exclusion Criteria: Smoker: Tobacco use within the last 12 months Dieting or intending to diet Use of potential confounding medications, e.g. Niacin containing drugs History of diabetes, heart disease or taking medication for those conditions History of hypertension (high blood pressure) not controlled with medication Pregnant or intending to become pregnant Unwillingness to undergo a three month control/run-in period, be randomized to any one of four intervention groups, submit to thigh muscle biopsies and all other study testing or continuously participate in a randomly assigned exercise training or lifestyle intervention program for six months Orthopedic limitations, musculoskeletal disease and/or injury Allergic to xylocaine (anesthetic or numbing medicine) Inability to give blood continuously through a catheter (please notify the study nurse of any difficulty you have experienced in the past when having your blood drawn; the study nurse will determine whether you are excluded for this reason) Unwillingness to exercise at least twice per week at the Duke Center for Living Health and Fitness Center during research study staff supervised times

Ages Eligible for Study
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Minimum Age: 45 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Low-Amount/Moderate Intensity Exercise<br>Aerobic exercise at 50% peak oxygen use/consumption expending approximately 1,000 calories per week equaling approximately 10 miles per week OR 2.5-3.5 hours per week | Behavioral: Aerobic Exercise<br>* Aerobic exercise at 50% peak oxygen use/consumption expending approximately 1,000 calories per week equaling approximately 10 miles per week OR 2.5-3.5 hours per week<br>|
| Other: High-Amount/Moderate-Intensity Exercise<br>Aerobic exercise at 50% peak oxygen use/consumption expending approximately 1,600 calories per week equaling approximately 16 miles per week OR 4-6 hours per week | Behavioral: Aerobic Exercise<br>* Aerobic exercise at 50% peak oxygen use/consumption expending approximately 1,600 calories per week equaling approximately 16 miles per week OR 4-6 hours per week<br>|
| Other: High-Amount/Vigorous-Intensity Exercise<br>Aerobic exercise at 75% peak oxygen use/consumption expending approximately 1,600 calories per week equaling approximately 16 miles per week OR 2-3 hours per week | Behavioral: Aerobic Exercise<br>* Aerobic exercise at 75% peak oxygen use/consumption expending approximately 1,600 calories per week equaling approximately 16 miles per week OR 2-3 hours per week<br>|
| Other: Low-Amount/Moderate-Intensity Exercise + Diet<br>Exercise - 150 minutes per week (30 minutes / 5 days per week) of aerobic exercise at 50% peak oxygen use/consumption equaling approximately 10 miles per week Diet - The CLI sessions will provide training on needed skills (e.g., calorie counting, portion size estimation) as well as motivation and support in a group counseling setting designed to achieve a weight loss goal of 5 to 7% of baseline body weight. | Behavioral: Exercise and Diet<br>* Exercise - 150 minutes per week (30 minutes / 5 days per week) of aerobic exercise at 50% peak oxygen use/consumption equaling approximately 10 miles per week Diet - The Clinical Lifestyle Intervention sessions will provide training on needed skills (e.g., calorie counting, portion size estimation) as well as motivation and support in a group counseling setting designed to achieve a weight loss goal of 5 to 7% of baseline body weight.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fasting Plasma Glucose |  | 3 month control and 6 months intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measures of Glucose control |  | 3 month control and 6 month intervention | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Abnormal fasting glucose