Home-Based HIT in Obese Individuals

Study Overview
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Brief Summary
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This study aims to investigate the efficacy of a novel home-based high-intensity interval training (Home-HIT) intervention in obese individuals, with elevated cardiovascular disease (CVD) risk. It was hypothesised that Home-HIT would 1) have high adherence to the prescribed exercise intensity (compliance), 2) improve markers of CVD risk, and 3) lead to favourable skeletal muscle adaptations.

Detailed Description
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The applicability of current high intensity interval training (HIT) protocols to the sedentary obese population has been disputed by public health experts. Existing HIT interventions have been successful only under optimal conditions with high levels of supervision and specialised equipment, creating further barriers to exercise in those most in need. We aimed to eliminate many of these barriers by modifying existing HIT protocols to create a new home-based HIT (Home-HIT) intervention tailored to individuals with low fitness and mobility. It was hypothesised that Home-HIT would 1) have high adherence to the prescribed exercise intensity (compliance) and 2) improve markers of cardiovascular disease (CVD) risk. 32 Obese adults with at least 3 additional CVD risk factors (age 36±2 y; BMI 34.3±0.8 kg∙m-2; VO2peak 24.6±1.0 ml∙kg∙min-1), completed one of three 12-week training programmes 3x/week: Home-HIT (n=9); Laboratory-based supervised HIT (Lab-HIT; n=10) or home-based moderate intensity continuous training (Home-MICT; n=13). Adherence and compliance were monitored online in almost real time using a heart rate (HR) monitor and mobile app. The Home-HIT group completed 4 progressing to 8 1min intervals interspersed with 1min of rest in an unsupervised place of their choosing. The intervals were composed of simple bodyweight exercises that required no equipment. Changes in VO2peak, insulin sensitivity, body composition, flow-mediated dilation (FMD) and aortic pulse wave velocity (PWV) were assessed. Muscle biopsies were taken to assess changes in capillarisation, mitochondrial density, intramuscular triglyceride (IMTG) content and eNOS and GLUT4 protein expression using quantitative immunofluorescence microscopy.

Official Title
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Effects of a 12-Week Home-Based High-Intensity Interval Training Programme in Obese Individuals With Elevated Cardiovascular Disease Risk: A Pilot Study

Conditions
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Obese

Intervention / Treatment
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* Behavioral: Training mode


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: obesity (BMI >30 kg/m2) age 18-55 Exclusion Criteria: diagnosed CVD and other contraindications to participate in an exercise intervention BMI <30 kg/m2

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 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: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Home-HIT<br>Home-based high-intensity interval training: participants performed 12 weeks of simple body weight exercises in a place of their own choosing 3x/week | Behavioral: Training mode<br>* type of exercise training completed for 12 weeks<br>|
| Experimental: Home-MICT<br>Home-based moderate-intensity interval training: participants performed 12 weeks of continuous exercise (running, swimming or cycling) in a place of their own choosing 3x/week | Behavioral: Training mode<br>* type of exercise training completed for 12 weeks<br>|
| Experimental: Lab-HIT<br>Laboratory-based high-intensity interval training: participants performed supervised cycle exercise under laboratory conditions 3x/week for 12 weeks | Behavioral: Training mode<br>* type of exercise training completed for 12 weeks<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in aerobic fitness | change in maximal aerobic capacity following the training | change in baseline aerobic fitness at 12 weeks | 
| Adherence and compliance to the exercise training intervention | Session completion rate (adherence) and ability to meet target heart rates (compliance) | adherance and compliance to the training over the 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in baseline FMD | endothelial function measured using flow-mediated dilation (FMD) | change in baseline FMD at 12 weeks | 
| change in vascular stiffness | change in vascular stiffness with training | change in baseline vascular stiffness at 12 weeks | 
| change in body fat percentage | change in body fat percentage using DXA with training | chage in baseline body fat percentage at 12 weeks |