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

This study has been completed.
Sponsor:
Collaborator:
Manitoba Institute of Child Health
Information provided by (Responsible Party):
Jon McGavock, University of Manitoba
ClinicalTrials.gov Identifier:
NCT00755547
First received: September 18, 2008
Last updated: March 27, 2013
Last verified: March 2013
  Purpose

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.


Condition Intervention Phase
Type 2 Diabetes Mellitus
Adolescent Obesity
Other: Aerobic Exercise Training
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Prevention
Official Title: Physical Activity for Overweight Youth at Risk for Type 2 Diabetes Mellitus (POWER) Trial

Resource links provided by NLM:


Further study details as provided by University of Manitoba:

Primary Outcome Measures:
  • Insulin sensitivity measured from Bergman's frequently sampled intravenous glucose tolerance test [ Time Frame: 6 months ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • 1H-Magnetic resonance spectroscopy-derived measure of lipid content in liver and muscle tissue [ Time Frame: 6 months ] [ Designated as safety issue: No ]

Enrollment: 120
Study Start Date: April 2008
Study Completion Date: January 2013
Primary Completion Date: January 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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

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.

  Eligibility

Ages Eligible for Study:   13 Years to 19 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

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.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00755547

Locations
Canada, Manitoba
Manitoba Institute of Child Health
Winnipeg, Manitoba, Canada, R3E3P4
Sponsors and Collaborators
University of Manitoba
Manitoba Institute of Child Health
Investigators
Principal Investigator: Jonathan M McGavock, PhD University of Manitoba
  More Information

No publications provided by University of Manitoba

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Jon McGavock, Associate Professor, University of Manitoba
ClinicalTrials.gov Identifier: NCT00755547     History of Changes
Other Study ID Numbers: SC-5-08-2489-JM, GRT2008-10
Study First Received: September 18, 2008
Last Updated: March 27, 2013
Health Authority: Canada: Health Canada
Canada: Canadian Institutes of Health Research

Keywords provided by University of Manitoba:
Childhood
insulin sensitivity
steatosis, spectroscopy

Additional relevant MeSH terms:
Diabetes Mellitus
Diabetes Mellitus, Type 2
Overweight
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Body Weight
Signs and Symptoms

ClinicalTrials.gov processed this record on September 18, 2014