Effects of Microbouts of Activity on Metabolic Health
Condition: Health Behavior
Study type: Interventional

Summary: 
      Population studies suggest that time spent in sedentary behaviors is associated with
      all-cause mortality including obesity, diabetes, and cardiovascular diseases, independent of
      time spent in exercise. Frequent interruptions to sedentary time are however beneficially
      associated with metabolic health outcomes, even in individuals who exercise regularly. The
      goal is to use integrative approach to understand the biological mechanisms that underlie
      these associations in a longitudinal intervention study in overweight sedentary adults. The
      investigators believe that the proposed study will provide an initial evidence base for the
      health benefits of breaking up prolonged sitting with short bursts of activity. This
      innovative strategy may be more effective at combating the adverse effects of sedentary
      behaviors than more traditional approaches.
    

Detailed description: 
      To compare the effects of 4-weeks of microbursts of moderate-intensity activity to a
      calorically equivalent single bout of 45 minutes of moderate-intensity exercise training,
      both performed 5 days per week for a total of 45 minutes, in free-living sedentary overweight
      adults on:

      Aim 1: plasma inflammatory and cardiometabolic health biomarkers in association with total
      energy expenditure and time spent in sedentary behaviors.

      H1: Microbursts of activity will result in higher daily energy expenditure and lower time
      spent sedentary, as respectively measured with doubly labeled water and accelerometry, than
      traditional exercise training. This will be associated with healthier inflammatory
      Interleukin 1 alpha (IL1a), Interleukin 6 (IL6), Interleukin 10 (IL10), Tumour Necrosis
      Factor alpha (TNFa) and cardiometabolic (triglycerides, cholesterol, C-Reactive Protein
      (CRP), High-density lipoprotein (HDL), and Low-density lipoprotein (LDL) profiles compared to
      those obtained with traditional exercise training program.

      Aim 2: 24-hr total fat and carbohydrate oxidation, exogenous carbohydrate oxidation, dietary
      fat trafficking between oxidation and incorporation into muscle lipid fractions, and
      mitochondrial function.

      H2: Both one single continuous bout and microbouts of activity will increase 24-hr total
      (whole-room calorimetry) and dietary (D9-palmitate) fat oxidation due to greater
      mitochondrial lipid oxidation (high resolution respirometry) and lower incorporation of
      dietary fatty acid into muscle lipid fractions (D9-palmitate), as compared to baseline
      sedentary control condition. Microbouts of activity will further result in greater increases
      in 24-hr total (whole-room calorimetry) and exogenous (U-13C6 glucose) carbohydrate oxidation
      and in mitochondrial carbohydrate-linked oxidation, than traditional isocaloric exercise
      training.

      Aim 3: Whole-body insulin sensitivity. H3: Both one single continuous bout and microbouts of
      activity will improve whole-body insulin sensitivity Intravenous Glucose Tolerance Test
      (IVGTT) compared to the baseline sedentary condition, but the improvement will likely be
      higher with the microbouts of activity.

      Exploratory aim: Self-perceived appetite, hunger, and levels of mood, fatigue and
      vigor/energy.

      H3: Microbursts of activity will result in less appetite, hunger and fatigue but in greater
      feelings of vigor and overall well-being than traditional isocaloric exercise training. As a
      result adherence to microbursts will be better than adherence to single bouts of physical
      activity.
    

Intervention name(s): Traditional Exercise Training; Daily Microbursts of Activity
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Participants will be asked to perform moderate-intensity exercise (brisk walking) for 45 minutes for 5 days/week for 4 weeks. This intervention corresponds to the current recommendations.; Participants will be asked to break up their sedentary activities of daily living for 5-minutes every hour for 10 hours, 5 days/week, by brisk walking for 4 weeks.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Sedentary Behavior