Exercise-Induced Metabolic Compensation; a Physiological Adaptive Response to Exercise Training

Study Overview
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Brief Summary
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The primary aim of this proposal is to identify changes in the volume of highly metabolic organs (liver, kidneys, and brain) that occur as a physiological adaptation to exercise training and lower the resting energy expenditure. Secondary aims are to identify changes in the metabolic efficiency of muscle in low levels of physical activity and evaluate the effects on components of total daily energy expenditure including the sleeping metabolic rate (SMR) and diet induced thermogenesis (DIT).

Detailed Description
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Using a clinical trial type protocol, 16 overweight (body mass index: 25-30 kg/m2) men (n=8) and women (n=8) aged 21 to 45 years will exercise for 3 months in a moderate intensity regimen of 20 kcal/week/kg body weight that reflects current recommendations for weight management. The volume of various organs will be measured pre- and post-exercise intervention using magnetic resonance imaging (MRI). A cycling ergometer with a varied workload will be used to assess muscle metabolic efficiency. Changes in overnight SMR and 4 hours post breakfast DIT will be evaluated by whole human room indirect calorimetry (metabolic chamber). In addition, free-living Total Energy Expenditure (TEE) will be measured for ten days pre- and post-intervention by doubly labeled water.

Official Title
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Exercise-Induced Metabolic Compensation; a Physiological Adaptive Response to Exercise Training

Conditions
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Exercise Training

Intervention / Treatment
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* Behavioral: Exercise training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Overweight [body mass index (BMI) 25-30 Exclusion Criteria: Participation in another exercise or weight loss program in the last 6 months Non-stable weight (>±5%) over the past 6 months Current regular exercise > 1 hour per week Smoking within the past 6 months Being post-menopausal, breastfeeding, pregnancy, or having been pregnant within the past 6 months Previous bariatric surgery Cardiopulmonary disease (e.g., recent myocardial infarction or unstable angina) Musculoskeletal or neuromuscular impairments that preclude exercise training Having other health issues include cancer, diabetes, thyroid disease, hypertension, chronic renal failure, cognitive impairments Use of drugs that potentially impact body metabolism.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: 16 overweight (body mass index: 25-30 kg/m2) men (n=8) and women (n=8) aged 21 to 45 years will exercise for 3 months in a moderate intensity regimen of 20 kcal/week/kg body weight
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention<br>Exercise in moderate intensity tailored individually to 20 kcal/kg/week (range 1500-2000 kcal/week) with a free choice to exercise at home/gym on a treadmill or outdoors. | Behavioral: Exercise training<br>* The first phase of the study will comprise two weeks of control phase when participants will not engage in any exercise training but will be monitored for total daily energy expenditure and its components (REE, SMR, and DIT) and assessed volume of metabolic organs and skeletal muscle efficiency. Next, participants will start the active phase. In the first two weeks, participants will perform 150 - 200 min/week of a moderate intensity exercise so that they can adapt to the new regime and avoid injury. All exercise training will be monitored using heart rate sensor (HR) to track exercise adherence and HR range goals. Changes in daily non-exercise physical activity and sedentary behavior will be assessed for 10 days pre- and post-intervention by a tri-axial accelerometer. All study participants will be instructed to consume their habitual diet and to maintain the same caloric intake.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To examine long-term changes in the volume of highly metabolic organs (brain, liver, and kidneys) as an adaptive metabolic response to exercise training | The volume of various organs will be measured using magnetic resonance imaging (MRI). | Pre- and post 12 weeks of exercise intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To evaluate the changes in skeletal muscle metabolic efficiency during non- exercise physical activity as an adaptive response to long-term exercise training | A cycling ergometer with a varied workload will be used to assess muscle metabolic efficiency | Pre- and post 12 weeks of exercise intervention | 
| To determine the effect of long-term exercise training on changes in sleeping metabolic rate as an adaptive response . | Changes in overnight sleeping metabolic rate will be evaluated by whole human room indirect calorimetry (metabolic chamber) | Pre- and post 12 weeks of exercise intervention | 
| To assess the effect of long-term exercise training on changes in diet induced thermogenesis as an adaptive response. | Changes in diet induced thermogenesis will be evaluated 4 hours post breakfast by whole human room indirect calorimetry (metabolic chamber) | Pre- and post 12 weeks of exercise intervention | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Metabolic adaptation, Energy expenditure, Exercise, Muscle