Erez David, Lieberman Harris R, Rafael Nadav, Ketko Itay, Moran Daniel S
The Department of Health Systems Management, Ariel University, Ariel, Israel.
Institute of Military Physiology, Israel Defense Forces (IDF) Medical Corps, Tel Hashomer, Israel.
J Sleep Res. 2025 Aug;34(4):e14400. doi: 10.1111/jsr.14400. Epub 2024 Nov 14.
This is the first study to provide valuable insights into the effects of the Israeli Navy's 20-h rotating watch schedule on submariners' alertness, mood states, risk-taking behaviours, and sleep. Specifically, we assessed the impact of the non-circadian-aligned schedule on cognitive performance, mood, and behavioural outcomes in a highly controlled submarine environment. A total of 20 male submariners participated in an at-sea mission, where their cognitive performance, mood states, risk-taking propensity, and caffeine consumption were measured. A psychomotor vigilance task (PVT) assessed alertness, the propensity for risky behaviour (Evaluation of Risks Scale) measured risk-taking behaviours, and the Profile of Mood States evaluated mood disturbances. Actigraphy was used to monitor sleep times. Data were analysed according to seven watch schedule segments. Submariners slept a mean (standard error of the mean [SEM]) of 8.3 (0.2) h/24 h, fragmented into 3.7 (0.8) h epochs. Caffeine consumption decreased at sea (mean [SEM] 149.3 [6.0] mg) compared to land (mean [SEM] 205.5 [7.2] mg; p = 0.027). In the PVT, premature responses significantly increased during Watch VI (5:00-8:00 p.m.) and Watch VII (8:00 p.m.-12:00 a.m.; p = 0.014). In the mood subscales, tension was significantly higher during Watch II (4:00-8:00 a.m.; p = 0.002), indicating greater stress. Risk-taking propensity significantly increased during afternoon shifts (p = 0.050). The 20-h watch schedule led to fragmented sleep, reduced alertness in the evening, worsened mood states in the early morning, and increased risk-taking propensity in the afternoon. These findings suggest the need for the Israeli Navy to establish evidence-based caffeine guidelines and optimise the watch schedule to improve submariners' sleep, performance, and overall well-being.
这是第一项深入研究以色列海军20小时轮值值班表对潜艇艇员警觉性、情绪状态、冒险行为和睡眠影响的研究。具体而言，我们在高度可控的潜艇环境中评估了与昼夜节律不同步的值班表对认知表现、情绪和行为结果的影响。共有20名男性潜艇艇员参与了一次海上任务，期间测量了他们的认知表现、情绪状态、冒险倾向和咖啡因摄入量。通过一项心理运动警觉任务（PVT）评估警觉性，采用风险评估量表测量冒险行为倾向，用情绪状态剖面图评估情绪障碍。使用活动记录仪监测睡眠时间。数据根据七个值班表时间段进行分析。潜艇艇员平均（平均标准误[SEM]）每天睡眠8.3（0.2）小时，睡眠被分割成3.7（0.8）小时的时段。与在陆地时相比（平均[SEM]205.5[7.2]毫克），在海上时咖啡因摄入量减少（平均[SEM]149.3[6.0]毫克；p = 0.027）。在PVT测试中，在第六班（下午5:00 - 8:00）和第七班（晚上8:00 - 凌晨12:00）期间，过早反应显著增加（p = 0.014）。在情绪子量表中，在第二班（凌晨4:00 - 8:00）期间紧张情绪显著更高（p = 0.002），表明压力更大。下午班次期间冒险倾向显著增加（p = 0.050）。20小时值班表导致睡眠碎片化、夜间警觉性降低、清晨情绪状态变差以及下午冒险倾向增加。这些研究结果表明，以色列海军需要制定基于证据的咖啡因指导方针，并优化值班表，以改善潜艇艇员的睡眠、表现和整体健康状况。
