Night Shift Work, On-shift Napping, and Endothelial Function: A Pilot Study
Condition: Blood Pressure; Endothelial Dysfunction
Study type: Interventional

Summary: 
      Cardiovascular disease (CVD) and CVD risk factors such as high blood pressure (BP) are
      disproportionately higher among night shift workers, including those who work in public
      safety and healthcare. The purpose of this pilot study is to assess feasibility of collecting
      data germane to key indicators of cardiovascular health (i.e., ambulatory blood pressure)
      repeatedly during a simulated night shift protocol. The primary outcome measure will be the
      number of participants for which at least 70% of required ambulatory BP measures were
      collected. A result of at least 10 participants/subjects will be considered feasible.
    

Detailed description: 
      Cardiovascular disease (CVD) and CVD risk factors such as high blood pressure (BP) are
      disproportionately higher among night shift workers, including those who work in public
      safety and healthcare. Risk of CVD events such as myocardial infarction and stroke are higher
      among shift workers than non-shift workers. Risk of atrial fibrillation is 1.22 times greater
      (95%CI 1.02, 1.45) among individuals that work 3-to-8 night shifts per month versus non-shift
      workers. A comprehensive explanation for why shift workers, especially night shift workers,
      are at greater risk of CVD is not yet available. However, some research suggests that night
      shift workers experience repeated exposure to sleep deprivation, which impacts normal
      patterns in BP and endothelial function. Endothelial dysfunction and disruption of normal BP
      patterns are independently linked to numerous indicators of CVD, including cardiac-related
      mortality.

      The purpose of this pilot study is to assess feasibility of collecting data germane to key
      indicators of cardiovascular health (i.e., ambulatory blood pressure) repeatedly during a
      simulated night shift protocol. Investigators propose a laboratory-based pilot study whereby
      participants (volunteers) complete two conditions. Condition one will include a 12-hour
      simulated night shift in our lab with no napping. Condition two will involve a 12-hour
      simulated night shift in our lab with a 45 minute nap at 0200 hours. Participants will be
      asked to wear monitoring devices for approximately 48 total hours with the last 12 hours of
      monitoring (from 1900 to 0700) to be in our lab.

      Aim 1: Assess the feasibility of collecting ambulatory BP measures (ABPM) and indicators of
      endothelial function at multiple time points prior to, during, and after simulated night
      shift work.

      The primary outcome measure will be the number of participants for which at least 70% of
      required ambulatory BP measures were collected. A result of at least 10 participants/subjects
      will be considered feasible.

      Aim 2: Characterize the impact of simulated night shift work and on-shift napping on BP
      dipping and endothelial function.

      Secondary endpoints include quantifying descriptive statistics (e.g., means and standard
      deviations) for BP dipping and endothelial function.
    

Intervention name(s): Brief on-shift nap
Intervention type(s): Behavioral
Intervention description(s): The brief nap opportunity will allow for a 45-minute nap between the hours of 0200 and 0300 during the in-lab 12-hour simulated night shift.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Randomized crossover study design
Masking: None (Open Label)
Primary purpose: Other
Keywords: Ambulatory Blood Pressure; Endothelial Dysfunction