NEAT and Insulin Sensitivity
Condition: Overweight
MeSH terms: Overweight; Insulin Resistance; Hypersensitivity
Study type: Interventional

Summary: 
      The effect of Non-Exercise Activity Thermogenesis (NEAT) or inactivity on insulin sensitivity
      and lipid metabolism is unclear. Research recently published shows that activities associated
      with everyday activities, summarized as NEAT, such as walking and standing, have a much
      greater role in energy expenditure than exercise. Therefore, the objective of the present
      study is to evaluate the effect of 4 days of inactivity (mainly sitting), 4 days of everyday
      activities (sitting, walking and standing), and 4 days of inactivity and exercise (sitting
      and biking) on glucose metabolism and insulin sensitivity using an oral glucose tolerance
      test, and on lipid metabolism in sedentary, overweight people. The investigators hypothesize
      that:

        1. 4 days of everyday activities (NEAT) will cause an increased glucose tolerance and
           increased insulin sensitivity compared to 4 days of inactivity in sedentary, overweight
           people.

        2. 4 days of exercise will improve glucose tolerance and insulin sensitivity more than 4
           days of NEAT with equal energy expenditure, in sedentary, overweight people.

        3. Fasting triglyceride will have the same course as glucose, mentioned in 1. and 2.
    

Detailed description: 
      To evaluate the effect of Non-Exercise Activity Thermogenesis (NEAT) on glucose and lipid
      metabolism in sedentary, overweight people, the subjects included in the study protocol will
      follow 3 times a certain activity program of 4 days. These activity programs are:

        -  Inactivity: 14 hours of sitting, 2 hours of everyday activities, 8 hours of sleeping or
           laying down per day.

        -  NEAT: 4 hours of walking, 8 hours of sitting, 2 hours of standing, 2 hours of everyday
           activities, 8 hours of sleeping or laying down per day.

        -  Exercise: 1 hour biking, 13 hours of sitting, 2 hours of everyday activities, 8 hours of
           sleeping or laying down per day.

      The subjects will be biking using a home trainer, measuring energy expenditure, and
      supervised by one of the members of the research team. They will bike until they have reached
      a certain amount of kCal. The subjects will wear two accelerometers during all 3 activity
      programs to evaluate the amount of each activity (sitting, walking, standing,
      laying/sleeping). The Computer Science and Applications (CSA) Actigraph accelerometer will be
      placed on the back and the Continuous Activity Monitor (CAM) Maastricht instrument on the
      leg. Furthermore, the subjects will be requested to note their activities and dietary intake
      in a diary. After every 4 days of each activity program, an oral glucose tolerance test will
      be performed in the morning (fasting state) of the next day (day 5). Before and 15, 30, 45,
      60, 90, 120 minutes after ingestion of 75 gram of glucose in water, blood will be drawn for
      measurements of glucose and insulin. Only at baseline (t=0 minutes), blood will be drawn to
      measure cholesterol, HDL, LDL, triglycerides, apoA and apoB.
    

Intervention name(s): NEAT; Exercise
Intervention type(s): Behavioral; Behavioral
Intervention description(s): 4 days of everyday activities, including 4 hours of walking, 8 hours of sitting, 2 hours of standing, 2 hours of everyday activities and 8 hours of sleeping or laying down per day; 4 days of activity program, including 1 hour biking (exercise), 13 hours of sitting, 2 hours of everyday activities and 8 hours of sleeping or laying down per day
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: insulin sensitivity