“In war,” he wrote, “there is perhaps no general condition which is more likely to produce a large crop of nervous and mental disorders than a state of prolonged and great fatigue.” The four factors of (1) physiological arousal caused by the stress of existing in what is commonly understood as a continual fight-or-flight-arousal condition, (2) cumulative loss of sleep, (3) the reduction in caloric intake, and (4) the toll of the elements—such as rain, cold,
