289 Rack curtains improve sailors’ sleeping conditions in berthing compartments of the United States Navy (USN) ships

Abstract

Introduction: Ambient light is one of the primary factors affecting sailor sleep in berthing compartments on USN ships. Each “rack” (i.e., bunk) has a curtain, however, intended only for privacy. Current rack curtain specifications do not address light-blocking properties. We assessed the effects of replacing existing, standard rack curtains with enhanced rack curtains that provide superior light-blocking in the sleeping environment. Methods: Longitudinal (∼2 weeks), naturalistic observation of sailors (N=52; 41 enlisted personnel) on a USN destroyer during deployment. The standard curtain was used for one week followed by one week with the enhanced light-blocking curtain. Sleep-related attributes (Epworth Sleepiness Scale-ESS, Insomnia Severity Index-ISI, Pittsburgh Sleep Quality Index-PSQI) were assessed at the end of each week. Actigraphy and rack temperature data (both inside and outside the rack) were collected throughout the study. Results are presented as median±median absolute deviation. Results: Participants slept on average 6.8±1.0 hours/day. ESS scores improved with decreases from 9.0±3.0 with standard curtains to 7.0±3.0 with the enhanced curtains (p=0.020). Sailors with normal daytime sleepiness improved from 33 (63.5%) with standard curtains to 40 (76.9%) with the enhanced curtains. ISI scores decreased from 11.0±3.0 to 8.0±2.0 in the two conditions (p<0.001). The number of Sailors with ISI scores ≥15 decreased from 11 (21.2%) with standard curtains to 8 (13.5%) with the enhanced curtains (p=0.103). PSQI scores (8.0±2.0), however, did not change between the control and the intervention periods (p=0.527). Preliminary analysis showed that, compared to outside the rack, temperature inside the rack was slightly warmer on average with new curtains (∼1 °F; p=0.096). Conclusion: Our results suggest that the enhanced curtains reduced average daytime sleepiness and severity of insomnia symptoms. A greater difference in rack temperature with the enhanced curtains was observed; however, this may be attributed to the ship sailing in southern latitudes during the intervention period. Ongoing analysis will provide more insight on the utility of the enhanced curtains and their efficacy in improving sleeping conditions.