Reduce Sedentary Behavior at Work
Condition: Sedentary Lifestyle; Obesity; Cardiovascular Risk Factor
Study type: Observational

Summary: 
      Prior research suggests that sedentary behavior is detrimental to health, independent of
      exercise activity. Sedentary behavior is defined as behaviors that involve low levels of
      energy expenditure ≤1.5 metabolic equivalents (including sitting, watching TV, reading, and
      driving). Due to the high burden of sedentary behaviors in modern-day societies, this has
      potential implications for novel intervention strategies to reduce sitting (outside of
      regular exercise activity) and improve health. In addition, the modern workplace fosters
      sedentary behavior, and sedentary jobs now make up more than 80% of the workforce. The goal
      of this project is to implement interventions to reduce sedentary behavior at work and
      evaluate their impact on physiologic parameters and markers of disease. Specifically, the
      investigators/study team will use direct measurement of vascular endothelial function as one
      of our outcomes. This is important since conduit artery endothelial function, assessed by
      arterial flow-mediated dilation (FMD), is a powerful indicator of vascular inflammation and
      predictor of future cardiovascular events.
    

Detailed description: 
      The hypothesis is that obese subjects with sedentary jobs at the Medical College of
      Wisconsin, when assigned use of a standing desk to encourage movement, will reduce their
      daily sedentary time and demonstrate improvement in physiologic parameters and disease
      markers from baseline through the end of the intervention.

      Prior intervention studies are limited and not randomized, but have shown a reduction in
      waist circumference and improvements in cholesterol when overall sitting time is reduced over
      a 3-6 month interval (with a standing or treadmill desk). None of these intervention studies
      have directly measured vascular endothelial function, as assessed by arterial flow-mediated
      dilation (FMD), an early indicator of cardiovascular disease, and a powerful predictor of
      future cardiovascular events and vascular inflammation. Improvements in arterial FMD (or
      endothelial function) are known to reduce the future risk of cardiovascular events.

      Due to differences in the energy requirement of lying down, sitting, and standing, there has
      been increased research interest in activity type classification based on posture. In the
      science of sedentary behaviors, this is an important distinction to consider when evaluating
      health outcomes, such as in the present study. Accelerometers (physical activity monitors)
      utilize piezoelectric crystal sensor technology to provide a measure of accelerations of the
      body during movement and have the advantage of capturing frequency, duration, and intensity
      of physical movement minute by minute. Accelerometer technology will be used to analyze the
      primary outcome of interest (sedentary time). The study team will collect information on
      standing time, sedentary bouts, daily steps, cadence (walking speed in steps/minute), and
      exercise activity. The study team will employ a compact and re-usable physical activity
      monitor that adheres to the subject's thigh. This will provide objective assessments of
      activity levels at baseline and during the intervention. This data can be translated into
      energy expenditure or activity intensity categories (METs) and even position (sitting verses
      standing). The monitor output is Excel-compatible and is ideal for comparing each subject's
      activity and physiological parameters from baseline to intervention.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Sedentary office workers at the Medical College of Wisconsin who spend greater than 75% of
        their (8 hours or longer) work-day sitting at a desk.
      
Biospecimen description: 
      blood (10 ml) and urine (10cc)