Naval Submarine Medical Research Laboratory, Groton, Connecticut, USA.
Leidos, Inc., Reston, Virginia, USA.
J Sleep Res. 2023 Oct;32(5):e13901. doi: 10.1111/jsr.13901. Epub 2023 Apr 5.
Submariners face many environmental and operational challenges to maintaining good sleep, including suboptimal lighting, shift work, and frequent interruptions. Anecdotally, many Sailors consume caffeine to alleviate the effects of poor sleep on alertness, mood, and performance; however, caffeine itself may also degrade sleep quantity and/or quality. This study provides the first exploration of the potential relationship between caffeine use and sleep onboard submarines. Objective measures (wrist actigraphy, available from 45 participants), self-report sleep metrics, and self-reported caffeine consumption were collected from 58 US Navy Sailors before and during a routine submarine underway at sea lasting 30 days. Contrary to expectations, less caffeine was reportedly consumed at sea (232.8 ± 241.1 mg) than on land prior to the underway (M = 284.4 ± 251.7 mg; X (1) = 7.43, p = 0.006), positive rather than negative relationships were observed between caffeine consumption and sleep efficiency (F = 6.11, p = 0.02), and negative relationships were observed between caffeine consumption and wake after sleep onset (F = 9.36, p = 0.004) and sleep fragmentation (F = 24.73, p < 0.0001). However, in contrast, higher caffeine consumption was also negatively related to self-reported sleep duration while at sea (F = 4.73, p = 0.03). This observational study is the first to measure relationships between caffeine consumption and sleep quantity and/or quality in a submarine environment. We propose that the unique submarine environment and the unique caffeine consumption patterns of submariners should be considered in the development of potential countermeasures for sleepiness.
潜艇兵在维持良好睡眠方面面临许多环境和操作挑战，包括光照不佳、轮班工作和频繁中断。有传闻称，许多水手为了缓解睡眠不佳对警觉性、情绪和表现的影响而摄入咖啡因；然而，咖啡因本身也可能降低睡眠的数量和/或质量。这项研究首次探索了潜艇上咖啡因使用与睡眠之间的潜在关系。从 58 名美国海军水手那里收集了客观测量（腕动描记法，来自 45 名参与者）、自我报告的睡眠指标和自我报告的咖啡因消耗，这些水手在为期 30 天的例行潜艇海上行动之前和期间。与预期相反，在海上报告的咖啡因摄入量（232.8 ± 241.1mg）比在海上行动之前（M=284.4 ± 251.7mg；X(1)=7.43，p=0.006）少，观察到咖啡因消耗与睡眠效率呈正相关（F=6.11，p=0.02），而与睡眠后觉醒（F=9.36，p=0.004）和睡眠片段化（F=24.73，p<0.0001）呈负相关。然而，相反的是，在海上时，较高的咖啡因摄入量也与自我报告的睡眠时间呈负相关（F=4.73，p=0.03）。这项观察性研究首次测量了在潜艇环境中咖啡因消耗与睡眠数量和/或质量之间的关系。我们提出，应该在制定针对困倦的潜在对策时考虑潜艇环境的独特性和潜艇水手独特的咖啡因消耗模式。
