High-intensity Intermittent Training for Obese Individuals
Condition: Obesity
MeSH terms: Obesity
Study type: Interventional

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:

        1. Three-day food diaries

        2. Anthropometric measurements (weight, height, waist and hips) using standard procedures;

        3. Body composition using dual energy x-ray absorptiometry (DEXA)

        4. RMR and resting respiratory exchange ratio (RER) using indirect calorimetry;

        5. Endothelial function assessed by flow-mediated dilation (FMD) of the brachial artery
           using vascular ultrasound according to current guidelines;

        6. Maximal oxygen uptake (VO2max) and fat oxidation, cardiac output and left ventricular
           function during exercise using a cycle ergometer;

        7. Muscle and fat biopsies

        8. Fasting and postprandial release of appetite related hormones (and subjective feelings
           of hunger/fullness using visual analogue scales - VAS).
    

Intervention name(s): High intensity training; short springs; Moderate intensity exercise
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): high-intensity intermittent sprinting (HIIS) (8 sec sprint:12 sec rest) for 12 weeks, 4 times a week; short duration sprints (SDS)(8 sec sprint:12 sec rest) for 12 weeks, 4 times a week
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Obesity; exercise; body composition; insulin sensitivity; appetite; food intake