Background: In the military context, high levels of physiological and psychological stress together can compromise individual’s ability to complete given duty or mission and increase dropout rates. The purpose of this study was to investigate if baseline physical fitness, body composition, hormonal and psychological factors could predict dropout from a 10-day intense winter military survival training. Methods: 69 conscripts volunteered to participate in the study. Physical fitness (muscle strength and power, muscle endurance, and aerobic fitness), body composition and hormonal variables (BDNF, testosterone, cortisol, SHBG, DHEAS, IGF-1) together with self-reported psychological factors (short five personality, hardiness, sense of coherence, stress, depression) were assessed prior the survival training. Results: During the survival training, 20 conscripts (29%) dropped out. Baseline aerobic fitness (hazard ratio, HR: 0.997, 95% CI: 0.994–0.999, p = 0.006) and serum cortisol (HR: 1.0006, 95% CI: 1.001–1.011, p = 0.017) predicted dropout in Cox regression model. Each 10 m increase in the 12 min running test decreased the risk for dropout by 3%. Conclusion: Although most of the physiological and psychological variables at the baseline did not predict dropout during a short-term winter survival military training, baseline information of aerobic fitness and serum cortisol concentration may be useful to target support for individuals at higher potential risk for dropout.

中文翻译：

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生理和心理因素可以预测从激烈的10天冬季军事生存训练中退出吗？

背景：在军事环境中，高水平的生理和心理压力会损害个人完成既定任务或任务的能力，并增加辍学率。这项研究的目的是调查基线体质，身体成分，激素和心理因素是否可以预测10天激烈冬季军事生存训练的辍学率。方法：69名应征入伍者自愿参加研究。身体健康（肌肉力量和力量，肌肉耐力和有氧健康），身体成分和荷尔蒙变量（BDNF，睾丸激素，皮质醇，SHBG，DHEAS，IGF-1）以及自我报告的心理因素（五人格短，坚韧，在生存训练之前评估了连贯感，压力，抑郁感。结果：在生存训练期间，有20名应征者（29％）退学了。在Cox回归模型中，基线有氧适应性（危险比，HR：0.997，95％CI：0.994-0.999，p = 0.006）和血清皮质醇（HR：1.0006，95％CI：1.001-1.011，p = 0.017）预计会下降。在12分钟的跑步测试中，每增加10 m，落下风险就会降低3％。结论：尽管基线时的大多数生理和心理变量不能预测短期冬季生存军事训练期间的辍学，但有氧健身和血清皮质醇浓度的基线信息可能有助于为潜在辍学风险较高的人群提供支持。