Effect of Breaking up Prolonged Sitting on Metabolic Flexibility
Condition: Health Behavior
Study type: Interventional

Summary: 
      The investigators propose in this project to determine the effect of 3 days of frequent
      interruption of prolonged sitting on metabolic health in healthy overweight sedentary adults
      (n=24), as compared to 3 days including a single long bout of isocaloric exercise or a
      control condition where subjects do not exercise but are subjected to prolonged sitting. The
      investigators believe that this proposed project will provide an initial evidence base for
      the health benefits of breaking up prolonged sitting with short bursts of moderate-intensity
      activity, like walking.
    

Detailed description: 
      Although public-health recommendations to engage in moderate-to-vigorous physical activity
      (at least 30min, 5 days / week) have been widely promulgated by the government, most people
      are physically inactive. Sedentary behaviors, like time spent sitting, are associated with
      serious implications on metabolic health, indicating that even in individuals who regularly
      exercise a reduction in time spent sitting can confer health benefits. Encouraging recent
      evidence shows that walking breaks throughout the day are an effective strategy to offset the
      deleterious effects of prolonged uninterrupted sitting. Further data however are needed to
      better understand the effect of these microbursts of activity along the day. The
      investigators propose in this project to determine the effect of 3 days of frequent
      interruption of prolonged sitting on metabolic health in healthy overweight sedentary adults
      (n=24), as compared to 3 days including a single long bout of isocaloric exercise or a
      control condition where subjects do not exercise but are subjected to prolonged sitting.
      Plasma glucose, insulin, triglycerides and free fatty acids concentrations and the use of
      substrate (glucose, fat or protein) to provide energy to the body in response to meals
      consumption will be measured on day 3 of each of these three conditions. The investigators
      will furthermore assess the ability of the participants to perform the interventions on
      physical activity at the end of each day over the three days of intervention (2 days in
      free-living conditions and one day in a controlled environment). The investigators believe
      that this proposed project will provide an initial evidence base for the health benefits of
      breaking up prolonged sitting with short bursts of moderate-intensity activity, like walking.
      This innovative strategy may be more effective at combating the adverse effects of sedentary
      behaviors than more traditional approaches like structured exercise.
    

Intervention name(s): Uninterrupted sitting; Sitting + 1 bout of activity; Sitting + microbursts of activity
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): Subjects will be asked to refrain for two days from any structured activity and to reduce any daily life activity (walking, taking the stairs, biking, etc.) in their daily life. On day 3, subjects will remain seated all day in the room calorimeter, except to rise from the chair to void.; Subjects will be asked to perform 45 minutes of moderate-exercise in the morning once per day for two days in their daily life. On day 3 they will remain seated all day in the room calorimeter, except to rise from the chair to void, and to perform one bout of 45-min moderate-intensity (defined below) walking on a treadmill at 1000.; Subjects will be asked to refrain from any structured exercise for two days but to walk for 5 minutes each hour between 1000 and 1800 in daily life. On day 3, subjects will rise from the seated position every hour for 9 hours from 1000 to 1800 to complete 5min moderate-intensity (defined below) walking on a treadmill, which represents a total of 45min.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Basic Science
Keywords: Sedentary Behavior