High-intensity Intermittent Training for Obese Individuals

Study Overview
=================
Brief Summary
-----------------
The most appropriate and effective exercise interventions for weight loss remain a matter of continued discussion and there is a need to identify sustainable exercise programs which successfully promote weight loss and benefit health. The primary objective of this study is to determine if high-intensity intermittent sprinting (HIIS) produces better results in terms of reducing metabolic and cardiovascular risk factors, with special emphasis to fat mass loss and insulin sensitivity in healthy obese volunteers compared with an iso-caloric program of moderate-intensity continuous cycling (MICC) (control condition following the international recommendations). We will also assess the impact of short duration sprints (SDS) in the above factors and to understand the potential mechanisms behind different outcomes among training programs. The overall hypothesis is that HIIS will lead to a greater reduction in metabolic and cardiovascular risk factors compared with MICC in healthy obese volunteers and that SDS will produce similar improvements in cardiovascular risk factors as the longer duration HIIS

Detailed Description
-----------------
Participants will be randomized to one of three groups: HIIS (8s sprint:12s rest) or MICC (control group) iso-caloric protocols (for the duration needed to induce a 250 kcal energy deficit) or SDS (8s sprint:12s rest) for 10 minutes for 12 weeks. The intervention groups will be matched for age, BMI and male/females ratio and participants will be asked not to change their normal diet throughout the study. Before and after the exercise intervention (12 weeks), participants will perform the following assessments: Three-day food diaries Anthropometric measurements (weight, height, waist and hips) using standard procedures; Body composition using dual energy x-ray absorptiometry (DEXA) RMR and resting respiratory exchange ratio (RER) using indirect calorimetry; Endothelial function assessed by flow-mediated dilation (FMD) of the brachial artery using vascular ultrasound according to current guidelines; Maximal oxygen uptake (VO2max) and fat oxidation, cardiac output and left ventricular function during exercise using a cycle ergometer; Muscle and fat biopsies Fasting and postprandial release of appetite related hormones (and subjective feelings of hunger/fullness using visual analogue scales - VAS).

Official Title
-----------------
High-intensity Intermittent Training to Maximize Metabolic and Cardiovascular Protection in Obese Individuals

Conditions
-----------------
Obesity

Intervention / Treatment
-----------------
* Behavioral: High intensity training
* Behavioral: short springs
* Behavioral: Moderate intensity exercise


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: weight stable on the last three months, not currently dieting to lose weight inactive lifestyle. Exclusion Criteria: History of endocrine/cardiovascular/pulmonary/kidney disease, anaemia, gout, depression or other psychological disorders, eating disorders, drug or alcohol abuse within the last two years current medication known to affect appetite or induce weight loss. planned surgery during the study period participation in another research study restraint score derived from the TFEQ>12 post-menopausal women

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Moderate intensity exercise<br>Moderate intensity exercise | Behavioral: Moderate intensity exercise<br> <br> |
| Experimental: High Intensity training<br>High Intensity intermittent training | Behavioral: High intensity training<br>* high-intensity intermittent sprinting (HIIS) (8 sec sprint:12 sec rest) for 12 weeks, 4 times a week<br>|
| Experimental: Short springs<br>short springs training | Behavioral: short springs<br>* short duration sprints (SDS)(8 sec sprint:12 sec rest) for 12 weeks, 4 times a week<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in body composition | Body composition assessed by DEXA | Baseline and after 12 weeks of training | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in insulin sensitivity | Insulin will be measured in fasting and for 3h after a test meal | Baseline and after 12 weeks of training | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Obesity, exercise, body composition, insulin sensitivity, appetite, food intake