SIT LESS 4: How Does Reducing Sitting Time Improve Glucose and Lipid Metabolism?

Study Overview
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Brief Summary
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Research has shown that replacing sitting time with low intensity physical activity (such as slowly walking and standing) has beneficial effects on metabolic health, like insulin sensitivity, comparable to improvements after sitting all day in combination with 1h streneous exercise. The main objective of this study is to investigate the underlying mechanisms responsible for improved insulin sensitivity after 4 days of sitting less compared to sitting and exercise in healthy obese women. Our secondary objective is to investigate the effects of sitting less on cardio metabolic parameters.

Official Title
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SIT LESS 4: How Does Reducing Sitting Time Improve Glucose and Lipid Metabolism? A Study to Identify Underlying Mechanisms

Conditions
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Overweight and Obesity

Intervention / Treatment
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* Other: Activity regime


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Signed informed consent Caucasian Postmenopausal women Aged 45-70 years at start of the study Body mass index (BMI) 25 - 35 kg/m2 Stable dietary habits (no weight loss or gain >5kg in the past 3 months) Sedentary lifestyle (not more than 2,5 hours of exercise per week in the past 3 months) Exclusion Criteria: Not able to complete the sitless try-out day according to the protocol Active diseases (cardiovascular, diabetes, liver, kidney, cancer or other) No use of medication interfering with investigated study parameters (as determined by responsible physician) Alcohol consumption of >2 servings per day Smoking in the past 6 months Participation in another biomedical trial which may have an effect on insulin sensitivity less than one month before the start of the study (screening visit) Mental or physical disability which interferes with physical activity Subjects with contra-indications for magnetic resonance imaging (MRI) Reported participation in night shift work 2 weeks prior to the start of the study (screening visit) and during study participation. Night work is defined as working between midnight and 6.00 AM.

Ages Eligible for Study
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Minimum Age: 45 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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Female

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: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sit regime<br>Subjects will follow the sit regime during four days. Each day consists of 14 hours sitting, 1 hour walking and 1 hour standing and 8 hours sleeping. | Other: Activity regime<br>* Activity regime of 4 days followed by a test day.<br>|
| Experimental: Sit less regime<br>Subjects will follow the sit less regime during four days. Each day will consist of 9 hours sitting, 3 hours walking, 4 hours standing and 8 hours sleeping. | Other: Activity regime<br>* Activity regime of 4 days followed by a test day.<br>|
| Experimental: Exercise regime<br>Subjects will follow the exercise regime during four days. Each day will consist of 13 hours sitting, 1 hour walking, 1 hour standing, 1 hour exercise and 8 hours sleeping. The cycle session will be at approximately 60% maximal power. Exact cycling intensity and duration will be calculated to ensure equal total energy expenditure between the sitting less and the exercise regime. | Other: Activity regime<br>* Activity regime of 4 days followed by a test day.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Insulin sensitivity | 2-step hyperinsulinemic euglycemic clamp | Day 5 of intervention period | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ex vivo skeletal muscle mitochondrial respiration | oxygraph | Day 5 of intervention period | 
| substrate oxidation | indirect calorimetry RER | Day 5 of intervention period | 
| Intrahepatic lipid content | magnetic resonance spectroscopy | Day 5 of intervention period | 
| Blood pressure | average resting blood pressure over 30 minutes | Day 5 of intervention period | 
| Plasma cardio metabolic markers | endothelial dysfunction score (average Z-score of log transformed plasma sVCAM1, sICAM1 and sE-selectin) | Day 5 of intervention period | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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insulin sensitivity, sitting time