Schilder Frank P M, de Weijer Antoin D, Levels Koen, Bruinsma Bastiaan, Geuze Elbert
Department of Psychiatry, University Medical Centre, Utrecht, the Netherlands; Brain Research and Innovation Centre, Ministry of Defence, Utrecht, the Netherlands.
Department of Psychiatry, University Medical Centre, Utrecht, the Netherlands; Brain Research and Innovation Centre, Ministry of Defence, Utrecht, the Netherlands.
Int J Psychophysiol. 2025 Feb;208:112491. doi: 10.1016/j.ijpsycho.2024.112491. Epub 2024 Dec 20.
Military personnel often encounter situations that can trigger acute stress, which may affect operational performance. Therefore, it is important to examine stress responses in controlled environments to obtain more insights in performance-influencing effects of acute stress. This study investigated the impact of passive heat exposure combined with virtual combat scenarios on cardiovascular and psychophysiological parameters in a controlled setting. Sixty-eight healthy servicemembers were randomized into a low-stress or high-stress condition. Both groups engaged in two virtual combat scenarios. The low-stress group, however, underwent testing under thermoneutral conditions (M = 22.4°C, M = 41.4%) whereas the high-stress group was exposed to passive heat exposure (M = 35.9°C, M = 66.4%) using a portable environmental facility. While virtual combat scenarios alone led to a decrease in heart rate variability (HRV) without affecting heart rate (HR), the addition of passive heat exposure elicited a more pronounced physiological stress response, characterized by significantly higher HR and lower HRV in the high-stress condition. However, no significant changes were observed in respiratory rate, salivary cortisol, or alpha-amylase levels across the conditions, suggesting that there was no activation of either the hypothalamic-pituitary-adrenal or the sympathetic-adrenal-medullary axis. Furthermore, subjective stress and anxiety scores did not differ between conditions, underscoring the physiological nature of the observed changes. Resultantly, the physiological response was likely a thermal reaction rather than an acute stress response. These findings highlight the importance of incorporating environmental stressors into military training protocols to enhance realism and prepare personnel for operational stressors. However, the mild response observed suggests that higher ambient temperatures and longer exposure times may be necessary to evoke a more robust stress response for effective stress inoculation training.
军事人员经常会遇到可能引发急性应激的情况，这可能会影响作战表现。因此，在可控环境中研究应激反应，以更深入了解急性应激对表现的影响很重要。本研究在可控环境下，调查了被动热暴露结合虚拟战斗场景对心血管和心理生理参数的影响。68名健康军人被随机分为低应激组或高应激组。两组都参与了两个虚拟战斗场景。然而，低应激组在热中性条件下进行测试（平均温度 = 22.4°C，平均相对湿度 = 41.4%），而高应激组使用便携式环境设施接受被动热暴露（平均温度 = 35.9°C，平均相对湿度 = 66.4%）。虽然仅虚拟战斗场景就导致心率变异性（HRV）降低，但不影响心率（HR），而增加被动热暴露引发了更明显的生理应激反应，其特征是在高应激条件下心率显著升高且HRV降低。然而，在不同条件下，呼吸频率、唾液皮质醇或α-淀粉酶水平均未观察到显著变化，这表明下丘脑-垂体-肾上腺轴或交感-肾上腺-髓质轴均未被激活。此外，不同条件下主观应激和焦虑评分没有差异，这突出了所观察到变化的生理性质。因此，生理反应可能是热反应而非急性应激反应。这些发现强调了将环境应激源纳入军事训练方案以提高逼真度并让人员为作战应激源做好准备的重要性。然而，观察到的轻微反应表明，可能需要更高的环境温度和更长的暴露时间才能引发更强有力的应激反应，以进行有效的应激接种训练。
