EXIT: Prospective Study of the Response to Exercise

N/ACompletedNCT02204670

University of Manitoba15 enrolled

Overview

Background : Regular exercise is a cornerstone in the prevention and the management of comorbidities. Unfortunately, the metabolic benefit of exercise training is not universal and varies among individuals. A main factor likely to explain the exercise training variability is the lack of empirical evidence on the determinants of exercise training. A series of muscle-derived cytokines have recently been discovered that (1) are released during exercise and (2) exert positive effects on peripheral tissues. Irisin is one of these novel "myokines" and might contributes to the metabolic adaptations to exercise training. Methods: The investigators will perform a pilot cohort study in which obese adolescents will perform resistance exercise training for 6 weeks. The main exposure variable will be the acute release of irisin during resistance exercise. The main outcome measures will be the change in hepatic triglyceride content and glucose area under the curve during a 75g, 2-hour oral glucose tolerance test. Study Hypothesis: The primary overall hypothesis is that the change in plasma Irisin with a single bout of exercise will be associated with the metabolic adaptations to 6 weeks of resistance training, specifically, the reductions in hepatic triglyceride content and post-prandial glucose excursions, in obese adolescents.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Liver Fat Type 2 Diabetes

Interventions

We will determine the amount of Irisin secreted after a single bout of resistance exercise. Participants will be stratified into 3 groups based on the degree of Irisin release during this acute bout of resistance exercise. The metabolic adaptations to the 4 weeks of resistance training will be compared between youth stratified according to the amount of Irisin released during the acute bout of resistance exercise.

Eligibility

Sex: ALLMin age: 12 YearsMax age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: 1. Adolescents (12-18 years) 2. Body mass index considered obese according to the International Obesity Task Force Exclusion Criteria: 1. Adolescents with medication-induced or type 1 diabetes 2. are currently being treated with corticosteroids or atypical antipsychotics, as these agents significantly influence carbohydrate metabolism 3. have an orthopaedic injury or chronic illness that would prevent them from performing the intervention 4. have experienced \>10% weight loss or enrolled in weight loss program within six months of enrolment 5. a history of alcoholism or drug abuse 6. require use of medication(s) known to affect insulin sensitivity or secretion within the last 30 days 7. medication(s) known to cause weight gain 8. anabolic steroids 9. weight loss medication(s) 10. pregnant or planning to be pregnant

Outcomes

Primary Outcomes

Hepatic Triglyceride Content

Hepatic triglyceride content will be measured by using 1H magnetic resonance spectroscopy. After image acquisition, a single voxel volume of interest will be placed in the upper right lobe of the liver in an area devoid of adipose tissue to acquire 1H spectra. A total of 64 spectra will be collected and averaged to determine the intracellular triglyceride content.

Time frame: 6 weeks

Secondary Outcomes

Post-prandial glucose

Glucose area under the curve (AUC) will be determined by summing the area under serum glucose measures between each 15- or 30-min segment using the trapezium rule during a frequently sampled 75-g oral glucose challenge .