Physical activity timing in relation to glycemic control for night workers versus day workers - PROJECT SUMMARY/ABSTRACT This project responds to PAR-24-075, “Stephen I. Katz Early Stage Investigator Research Project Grant.” The PI is a methodologist with expertise in sensor-based assessments of physical activity (PA), and the project will transition him into a new area of research focused on glycemic control in night workers. As of 2015, nearly 11 million Americans engaged in frequent night work (defined as working between 1:00am and 5:00am), which is a known correlate of impaired glycemic control. PA can combat this issue, but the effects are timing-dependent, with current guidance suggesting the ideal time window falls <3 hours from the largest meal of the day and >1 hour before bed. Night workers are underrepresented in this evidence base, and because of their unique biological, behavioral, and environmental characteristics, it is unclear if their ideal time window matches the current recommendation. The current project’s central hypothesis is that the windows do not match, i.e., that optimal PA timing differs between night workers and day workers. To test that hypothesis, a sample of non-diabetic night workers (n=200) and day workers (n=200) will be recruited from the transportation, healthcare, manufacturing, retail, and leisure/hospitality industries in the Chicagoland region. Each participant will wear a continuous glucose monitor and a PA monitor in their everyday settings for two weeks. Throughout the measurement, they will also provide information about their work schedule, meal/sleep timing, and perceived barriers and facilitators to PA at different times of day. With this information, the first aim will be to compare the timing-related profiles of night workers and day workers, in terms of when participants are most active, how their PA bouts are timed with respect to other daily events (e.g., meal times, sleep onset, and work/leisure context), and day-to-day regularity of PA habits. This information—alongside the reported barriers and facilitators of PA at different times—will give an overall picture of the unique behavioral patterns and PA-related attitudes of night workers versus day workers. The second aim will be to determine associations between PA timing and glycemic control by cross-referencing each group’s timing-related profile of PA against data from the continuous glucose monitors. This will provide evidence to suggest whether night workers should adhere to current timing-related guidance, or whether customized guidance is needed. Either result would provide critical information, but the latter is more likely, in which case the study data would be positioned to support the development of preliminary guidance for night workers. Broader impacts of the project will be to 1) suggest potential mechanisms of action for examination in future laboratory studies, and 2) support the development of interventions that deliver strategically-timed PA for improving glycemic control in night workers.
