Erez David, Lieberman Harris R, Baum Ido, Ketko Itay, Moran Daniel S
The Department of Health Systems Management, Ariel University, Ariel, Israel.
Institute of Military Physiology, IDF Medical Corps, Tel Hashomer, Israel.
Front Neurosci. 2024 Jun 21;18:1419181. doi: 10.3389/fnins.2024.1419181. eCollection 2024.
This observational study investigated the effects of sleep deprivation and ad libitum caffeine consumption on cognitive performance, risk behavior, and mood among 28 Israeli Special Forces (SF) soldiers (mean age: 20.57 ± 0.92 years) during a 96-hour combat exercise.
Actigraphy was used to monitor sleep and activity; cognitive function, risk-taking propensity, mood states, and self-reported sleepiness were assessed using the Psychomotor Vigilance Task (PVT), Evaluation of Risks Scale (EVAR), Profile of Mood States (POMS), Karolinska Sleepiness Scale (KSS); and caffeine consumption by questionnaire at 0, 50, and 96 hours. For analyses, participants were divided into Low (<400 mg) and High (≥400 mg) caffeine consumption groups.
The soldiers hiked 108.5 ± 0.52 km and slept for 12.7 ± 0.5 h, with a notable transition from multiple short sleep epochs in the initial 50 hours to a consolidated 5-hour sleep period subsequently. In the High caffeine group, PVT reaction time was faster ( = 0.024) compared to the Low caffeine group, with fewer premature response errors ( = 0.026). However, this group showed increased risk-taking ( = 0.037), particularly reduced Self-Control ( = 0.010). No significant impact of caffeine intake on mood was observed. However, degradation over the course of the exercise in both groups in mood states, including anger, fatigue, tension, and vigor, was noted ( < 0.05). KSS scores increased significantly at 50 and 96 h ( < 0.001).
These results suggest that while caffeine enhances cognitive function, its ad libitum consumption did not consistently improve these measures in this cohort of SF soldiers. The study highlights the complex relationship between sleep deprivation and caffeine intake and their combined effects on soldiers' cognitive and behavioral functions, indicating a need for evidence-based caffeine use guidelines for using caffeine in military settings.
这项观察性研究调查了28名以色列特种部队（SF）士兵（平均年龄：20.57±0.92岁）在96小时战斗演习期间，睡眠剥夺和随意摄入咖啡因对认知表现、风险行为和情绪的影响。
使用活动记录仪监测睡眠和活动；使用心理运动警觉任务（PVT）、风险评估量表（EVAR）、情绪状态剖面图（POMS）、卡罗林斯卡嗜睡量表（KSS）评估认知功能、冒险倾向、情绪状态和自我报告的嗜睡程度；并通过在0、50和96小时时的问卷调查来评估咖啡因摄入量。为了进行分析，将参与者分为低咖啡因摄入量组（<400毫克）和高咖啡因摄入量组（≥400毫克）。
士兵们徒步108.5±0.52公里，睡眠12.7±0.5小时，从最初50小时的多个短睡眠时段显著过渡到随后的5小时连续睡眠时间。在高咖啡因组中，与低咖啡因组相比，PVT反应时间更快（=0.024），过早反应错误更少（=0.026）。然而，该组显示出冒险行为增加（=0.037），尤其是自我控制能力下降（=0.010）。未观察到咖啡因摄入量对情绪有显著影响。然而，两组在演习过程中情绪状态，包括愤怒、疲劳、紧张和活力方面均出现下降（<0.05）。KSS评分在50和96小时时显著增加（<0.001）。
这些结果表明，虽然咖啡因可增强认知功能，但在这群特种部队士兵中，随意摄入咖啡因并不能持续改善这些指标。该研究突出了睡眠剥夺与咖啡因摄入之间的复杂关系及其对士兵认知和行为功能的综合影响，表明需要基于证据的咖啡因使用指南，以便在军事环境中使用咖啡因。
