Effects of Exercise Intensity in Obese Children and Adolescents

Study Overview
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Brief Summary
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The prevalence of paediatric obesity has increased over the last two decades and with it, an increased diagnosis of lifestyle-related diseases in children and adolescents. High intensity interval training has recently been explored as an alternate to traditional aerobic exercise in adults with chronic disease and has potential to induce rapid reversal of subclinical disease markers in obese children and adolescents. High intensity interval training has recently been explored as an alternate to traditional aerobic exercise in adults with chronic disease and has potential to induce rapid reversal of subclinical disease markers in obese children and adolescents. Goal: The primary aim of this randomised controlled trial is to evaluate the effectiveness of a high intensity interval training intervention on myocardial function, vascular function and visceral adipose tissue in obese children and adolescents at baseline, three and twelve months. Method: Multi-centre randomised controlled trial of 100 obese children and adolescents in the cities of Trondheim (Norway) and Brisbane (Australia). Participants will be randomised to (1) high intensity interval training, (2) moderate intensity continuous training or (3) nutrition advise. Participants will partake in supervised exercise training and/or nutrition consultations for 3 months. Measurements for all study endpoints will occur at baseline, 3 months (post intervention) and 12 months (follow up). Scientific Significance : This randomised controlled trial will general substantial information regarding the effects of exercise intensity on paediatric obesity, specifically the cardio-metabolic health of this at-risk population. It is expected that communication of results will allow for more robust and realistic guidelines regarding exercise prescription in this population to be formed while outlining the benefits of high intensity interval training on subclinical markers of disease.

Detailed Description
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Worldwide, childhood overweight and obesity rates are approximately 10%, this high incidence attributed to a physically inactive lifestyle and inappropriate nutrition. Early cohort studies illustrated that fifty per cent of obese children became obese adults and consequently had an higher risk for metabolic syndrome than obese adults who were not obese as children. Both female and male overweight children and adolescents had a 30% increase in all cause mortality. The increases in risk of death were independent of adult body mass index. Systematic reviews suggest that lifestyle and exercise interventions in obese children and adolescents can lead to improvements in anthropometric and cardio-metabolic outcomes, but these are not inclusive of several important outcomes such as myocardial and vascular function or visceral adipose tissue.

Official Title
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A Multi-centre Randomized Controlled Trial Examining the Effects of High Intensity Interval Training on Cardio-metabolic Outcomes in Obese Children and Adolescents

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: High intensity interval training
* Behavioral: Moderate intensity continuous training
* Dietary Supplement: Nutritional advice


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Obese (BMI ≥ 95th percentile - age and sex specific criteria) Exclusion Criteria: Elevated blood pressure (≥ 95th percentile for systolic or diastolic values) Congenital heart disease Coronary artery disease Family history of hypertropic obstructive cardiomyopathy Any abnormality during rest or stress echocardiography which indicates it would be unsafe to participate Self reported kidney failure Any major organ transplant Considerable pulmonary disease including severe or poorly controlled asthma Smoking Diabetes Epilepsy or a history of seizures Orthopaedic or neurological limitations to exercise Diagnosed attention deficit hypersensitivity disorder Steroid medications Participation in another research study

Ages Eligible for Study
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Minimum Age: 7 Years
Maximum Age: 16 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: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High intensity interval training<br>10-minute warm up at 60-70% of maximal heart rate (HRmax). Then walking, running or cycling at 85-95% of maximal heart rate at intervals of 4 x 4 minutes, with 3 minute active breaks (50-70% of HRmax) between intervals. A 5-minute cool down period. | Behavioral: High intensity interval training<br>* Twelve weeks of 2-3 supervised training sessions each week.<br>* Other names: HIIT;Dietary Supplement: Nutritional advice<br>* healthy food choices, portion sizes and regular mealtimes<br>|
| Experimental: Moderate intensity continuous training<br>walking, running or cycling continuously at 60-70% HRmax for 44 minutes. | Behavioral: Moderate intensity continuous training<br>* Twelve weeks of 2-3 supervised training sessions each week.<br>* Other names: MICT;Dietary Supplement: Nutritional advice<br>* healthy food choices, portion sizes and regular mealtimes<br>|
| Active Comparator: nutritional advice<br>10 individual nutrition consultations with an accredited dietitian over the 12 month period. Content of consultations will include healthy food choices, portion sizes and regular mealtimes. | Dietary Supplement: Nutritional advice<br>* healthy food choices, portion sizes and regular mealtimes<br>|
| No Intervention: non-obese children<br>100 healthy non-obese children aged 7-16 (controls) | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak systolic tissue velocity | systolic tissue Doppler velocity assessed during resting and stress echocardiography | 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subcutaneous and total abdominal adipose tissue | Assessed using MRI | 12 weeks, 12 months | 
| Cardiorespiratory fitness (VO2peak) | Assessed using a maximal treadmill test | 12 weeks, 12 months | 
| Body composition | Assessed using DXA (UQ), BodPod (NTNU) | 12 weeks, 12 months | 
| Blood biochemistry | Analysed for lipids, glucose, insulin, inflammatory makers, satiety hormones, oxidative stress | 12 weeks, 12 months | 
| Physical activity | Assessed through 7 day accelerometry | 12 weeks, 12 months | 
| Dietary analysis | Assessed through a three-day food record | 12 weeks, 12 months | 
| Myocardial structure and cardiac adipose tissue (UQ) | Assessed through cardiac MRI; participants > 12 years only | 12 weeks | 
| Arterial stiffness | Assessed through pulse wave velocity and pulse wave analysis | 12 weeks, 12 months | 
| Autonomic function | Assessed through heart rate variability and heart rate recovery | 12 weeks, 12 months | 
| Quality of life | Assessed through the Paediatric Quality of Life Inventory | 12 weeks, 12 months | 
| Visceral adipose tissue | assessed by magnetic resonance imaging (MRI) | 12 weeks, 12 months | 
| Vascular function | Assessed through flow mediated dilation procedure | 12 weeks, 12 months | 
| Peak systolic tissue velocity | systolic tissue Doppler velocity assessed during resting and stress echocardiography | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Exercise, Myocardial function, Vascular function, Cardiovascular disease/prevention & control, Paediatric obesity, Visceral adipose tissue