NCT04469803

Impact of Intra-Shift Napping on EMS Cardiovascular Health

The Impact of Napping During Night Shifts on Indicators of Cardiovascular Health Among EMS Clinicians

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 28 (actual)
• Sponsor: University of Pittsburgh · Academic / Other
• Sex: All
• Age: 18 Years – 100 Years
• Healthy volunteers: Accepted

Summary

Cardiovascular disease (CVD) exerts a significant health burden among shift workers, including police, firefighters, and emergency medical services (EMS). The unique occupational demands inherent to these professions--sleep loss, circadian misalignment, high stress, and sustained hyper-vigilance--confer increased risk for both on and off-duty cardiovascular events. Mitigating cardiovascular risks in these professions requires that we first identify robust markers and potential mechanisms of risk. Previous work suggest shift work has a negative impact on blood pressure (BP) and heart rate variability (HRV). Blunted BP dipping at night and during sleep, and reduced HRV are powerful markers of increased CVD risk. Both are linked to preclinical indicators of cardiac damage, such as presence of coronary artery calcium, left atrial enlargement, and cardiovascular-related mortality. This study will use an experimental crossover study design with three intervention conditions to test the impact of a 30 minute brief nap and a 2-hour longer nap versus no nap on BP and HRV. Outcomes of interest include blunted dipping of BP during nighttime hours and during sleep and HRV.

Detailed description

Cardiovascular disease (CVD) exerts a significant health burden among shift workers, including police, firefighters, and emergency medical services (EMS). The unique occupational demands inherent to these professions--sleep loss, circadian misalignment, high stress, and sustained hyper-vigilance--confer increased risk for both on and off-duty cardiovascular events. Mitigating cardiovascular risks in these professions requires that we first identify robust markers and potential mechanisms of risk. Previous work suggest shift work has a negative impact on blood pressure (BP) and heart rate variability (HRV). Blunted BP dipping at night and during sleep, and reduced HRV are powerful markers of increased CVD risk. Both are linked to preclinical indicators of cardiac damage, such as presence of coronary artery calcium, left atrial enlargement, and cardiovascular-related mortality. Critical questions remain: Are BP dipping and HRV impacted by napping during night shift work? Compared to those who do not nap, does napping during night shifts help BP and HRV to normalize quicker in the hours immediately post night shift work? What is the impact of brief naps (e.g., 30 minutes) versus longer naps (e.g., 2 hours)? This study will use a randomized crossover experimental design of EMS workers and be based in the laboratory environment. Participants will complete three intervention conditions. All study arms will involve a 12-hour simulated night shift. The intervention of interest is napping (no nap vs. a 30 minute nap vs. a two-hour nap) in a randomized crossover study design. The primary outcome of interest is BP dipping (\>10% drop) and Heart Rate Variability (HRV) measured as the standard deviation of inter-beat intervals of the sinus beats in milliseconds (SDNN). All outcomes will be measured serially before the simulation, during simulated night shifts, during the intra-shift napping period, and during recovery.

Conditions

• Blood Pressure
• Heart Rate Variability

Interventions

Type	Name	Description
BEHAVIORAL	Intra-Shift Napping	The Brief Nap opportunity will allow for a 30-minute nap between the hours of 0200 and 0400 during the 12-hour simulated night shift. The Longer Nap opportunity will allow for a 2-hour nap between the hours of 0200 and 0400 during the 12-hour simulated night shift.

Timeline

• Start date: 2021-03-01
• Primary completion: 2022-10-02
• Completion: 2022-10-02
• First posted: 2020-07-14
• Last updated: 2023-05-06

Locations

1 site across 1 country: United States