Medical and Physiological Benefits of Reduced Sitting

Study Overview
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Brief Summary
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The most important objective of this randomized controlled trial in subjects with increased cardiovascular and metabolic risk factors is to investigate whether only reduced daily sitting improves human cardiovascular and metabolic health during a six-month intervention. It is hypothesized and expected that only reduced sitting, without formal physical activity or exercise training, affects favorably cardiovascular and metabolic health.

Official Title
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Medical and Physiological Benefits and Mechanisms of Reduced Sitting Without Meeting the Current Physical Activity Recommendations

Conditions
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Metabolic Syndrome, Physical Activity, Insulin Resistance, Cardiovascular Diseases

Intervention / Treatment
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* Behavioral: Reduced sitting


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Physically inactive (less than 120 minutes of moderate intensity exercise per week measured by the activity monitor during run-in) Sitting time ≥ 10 h /day (measured by the activity monitor during run-in) BMI 25-40 Blood pressure < 160/100 mmHg Fasting plasma glucose < 7.0 mmol/l Fulfills the criteria of the metabolic syndrome according to Alberti et al 2009 Exclusion Criteria: History of a cardiac event Insulin or medically treated diabetes Any chronic disease or condition that could create a hazard to the subject safety, endanger the study procedures or interfere with the interpretation of study results Presence of ferromagnetic objects that would make MR imaging contraindicated Abundant use of alcohol Use of narcotics Smoking of tobacco or consuming snuff tobacco Diagnosed depressive or bipolar disorder Previous PET imaging or considerable exposure to radiation

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 65 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: A parallel-group randomised controlled trial
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Reduced sitting<br>Objectively measured daily inactive time will be reduced by one hour compared to the baseline. | Behavioral: Reduced sitting<br>* Subjects are guided to limit their sitting time during the day for 1 hour/day, by adding light activity with the help of an activity monitor. Subjects are not encouraged to increase their moderate to vigorous physical activity levels.<br>|
| No Intervention: Control<br>Subjects will be guided to maintain their normal sedentary behaviour and physical activity habits. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The change in whole-body insulin sensitivity | M-value during the hyperinsulinemic euglycemic clamp | The change from baseline to 6 months | 
| The change in skeletal muscle insulin-stimulated glucose uptake | Glucose uptake in the femoral muscles will be measured by positron emission tomography (PET) with [18F]-labelled fluoro-deoxy-glucose (FDG) tracer during hyperinsulinemic euglycemic clamp | The change from baseline to 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| daily sitting hours | Accelerometry data will be collected during the whole intervention period by a triaxial hip-mounted accelerometer | through study completion, an average of 6 months | 
| daily hours spent physically active | Accelerometry data will be collected during the whole intervention period by a triaxial hip-mounted accelerometer | through study completion, an average of 6 months | 
| The change in liver adiposity | Liver fat content will be assessed using magnetic resonance spectroscopy (MRS) | The change from baseline to 6 months | 
| The change in maximal oxygen uptake | Maximal oxygen uptake (VO2peak) will be determined by cycle ergometry with direct respiratory measurements. Exercise intensity will be started at 50 W and the intensity will be increased by 25 W at every two minutes until the criteria used to establish the VO2peak are met. The criteria used to establish the VO2peak are a plateau in VO2 despite of an increase in intensity and a respiratory quotient greater than 1.1. or volitional fatigue. | The change from baseline to 6 months | 
| The change in body fat percentage | Air displacement plethysmography (the Bod Pod system, COSMED, Inc., Concord, CA, USA) will be used to measure body composition (fat mass and fat free mass) with thoracic gas volume being predicted. | The change from baseline to 3 months | 
| The change in body fat percentage | Air displacement plethysmography (the Bod Pod system, COSMED, Inc., Concord, CA, USA) will be used to measure body composition (fat mass and fat free mass) with thoracic gas volume being predicted. | The change from baseline to 6 months | 
| The change in plasma glucose | Plasma glucose content will be measured from fasting venous blood samples using standard assays | The change from baseline to 3 months | 
| The change in plasma glucose | Plasma glucose content will be measured from fasting venous blood samples using standard assays | The change from baseline to 6 months | 
| The change in HbA1c | Glycated hemoglobin will be measured from fasting venous blood samples using standard assays | The change from baseline to 3 months | 
| The change in HbA1c | Glycated hemoglobin will be measured from fasting venous blood samples using standard assays | The change from baseline to 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Physical Activity, Metabolic Syndrome, Insulin Sensitivity, Cardiovascular Risk Factor, Sedentary Lifestyle, Accelerometry