A Study of the Effects of Exercise Intensity on Insulin Sensitivity in Overweight Youth (POWER)

March 27, 2013 updated by: Jon McGavock, University of Manitoba

Physical Activity for Overweight Youth at Risk for Type 2 Diabetes Mellitus (POWER) Trial

Background:

The investigators know that exercise helps children develop strong bones and muscles and generally stay healthy. What is unclear however, is how much exercise a child needs to lower their risk of developing type 2 diabetes.

Objective:

The investigators will try to find out whether high-intensity exercise for a short-period of time is better than moderately intense exercise for improving the diabetes risk profile in teens who are at risk for type 2 diabetes.

The working hypothesis is that exercise-mediated improvements in insulin sensitivity (a risk factor for diabetes) will be greater following vigorous intermittent physical activity than following low intensity physical activity in overweight adolescents 13-18 yrs at risk for T2DM.

Brief Description of Research Project: Teenagers between the ages of 13 and 18 yrs, who are at risk for type 2 diabetes (either by their family history or an abnormal response to sugar) will be randomly assigned to one of two activity groups or a control group. The activity groups will have supervised exercise sessions 3 to 5 days per week for 6 months. One group will do high-intensity exercise, and the other will do lower-intensity exercise. We will measure how sensitive their body is to insulin and the amount of fat in their muscle and liver tissue at the beginning and end of the exercise intervention.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The Physical activity for OverWEight youth at Risk for type 2 diabetes (POWER) Trial is a randomized controlled clinical trial designed to study the effects of aerobic exercise training regimens differing in intensity (relative to peak fitness) on insulin sensitivity in overweight youth. Additionally, this trial will explore the biologic mechanisms through which chronic physical activity alters lipid metabolism to result in improvements in insulin sensitivity.

We will recruit 90 eligible adolescents and randomly assign them to one of two six-month intervention arms that differ by intensity but elicit similar amounts of energy expenditure: (1) a low intensity continuous activity arm (40-55% of peak oxygen uptake for 60 min); (2) vigorous intensity intermittent activity arm (70-85% of peak oxygen uptake for 30 min) or a sedentary control group. The primary outcome measure of this trial will be insulin sensitivity, measured directly from Bergman's frequently sampled intravenous glucose tolerance test.

Study Type

Interventional

Enrollment (Actual)

120

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Manitoba
      • Winnipeg, Manitoba, Canada, R3E3P4
        • Manitoba Institute of Child Health

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

13 years to 19 years (Child, Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion criteria:

  • Ethnic minority considered at risk for T2DM
  • In utero exposure to hyperglycemia (i.e. mother with gestational or frank diabetes during pregnancy) and/or evidence of hepatic steatosis (serum ALT > 60U/L, ultrasound or MRI-based evidence of steatosis).

Exclusion criteria:

  • The investigators will exclude any patients that may have altered insulin sensitivity or tissue lipid content that would confound (mask) the effects of the intervention.

  • These include overweight adolescents who:

    • are diagnosed with impaired glucose tolerance or type 2 diabetes
    • are currently being treated with corticosteroids or atypical antipsychotics, as these agents significantly influence carbohydrate metabolism
    • are undergoing puberty (Tanner Stage 2-4) at the time of the investigation, as it is associated with transient changes in insulin sensitivity
    • have an orthopaedic injury that would prevent them from performing the intervention
    • have experienced weight loss or enrolled in weight loss program in the six months prior to the study
    • have a history of alcoholism or drug abuse.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: High Intensity
70-85% of peak oxygen uptake for 30 min 3-5 days/week.
Other: Aerobic Exercise Training
All sessions will be designed to elicit a certain degree of energy expenditure that will progressively increase throughout the trial. Adolescents randomized to the vigorous activity group will perform interval sessions that ensure an average heart rate between 70 and 85% of maximal heart rate reserve while those randomized will perform aerobic activity between 40 and 50% of heart rate reserve. The goal for the trial will be to expend a minimum of 350 kcal. The type of exercise will depend on the preference of each participant however, during the supervised sessions walking/jogging on a treadmill or outdoors will be used to elicit exercise intensities. The three activity sessions held at the YMCA-YWCA facilities in Winnipeg and be supervised by a trained kinesiologist who will record heart rate and perceived exertion for each session.
Experimental: Low Intensity
40-55% of peak oxygen uptake for 60 min 3-5 days/week
Other: Aerobic Exercise Training
All sessions will be designed to elicit a certain degree of energy expenditure that will progressively increase throughout the trial. Adolescents randomized to the vigorous activity group will perform interval sessions that ensure an average heart rate between 70 and 85% of maximal heart rate reserve while those randomized will perform aerobic activity between 40 and 50% of heart rate reserve. The goal for the trial will be to expend a minimum of 350 kcal. The type of exercise will depend on the preference of each participant however, during the supervised sessions walking/jogging on a treadmill or outdoors will be used to elicit exercise intensities. The three activity sessions held at the YMCA-YWCA facilities in Winnipeg and be supervised by a trained kinesiologist who will record heart rate and perceived exertion for each session.
No Intervention: Sedentary Control
Regular activities of daily living for 6 months

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Insulin sensitivity measured from Bergman's frequently sampled intravenous glucose tolerance test
Time Frame: 6 months
6 months

Secondary Outcome Measures

Outcome Measure
Time Frame
1H-Magnetic resonance spectroscopy-derived measure of lipid content in liver and muscle tissue
Time Frame: 6 months
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Manitoba

Collaborators

Manitoba Institute of Child Health

Investigators

  • Principal Investigator: Jonathan M McGavock, PhD, University of Manitoba

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2008

Primary Completion (Actual)

January 1, 2013

Study Completion (Actual)

January 1, 2013

Study Registration Dates

First Submitted

September 18, 2008

First Submitted That Met QC Criteria

September 18, 2008

First Posted (Estimate)

September 19, 2008

Study Record Updates

Last Update Posted (Estimate)

March 29, 2013

Last Update Submitted That Met QC Criteria

March 27, 2013

Last Verified

March 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SC-5-08-2489-JM
  • GRT2008-10

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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