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Updated: Feb 10, 2026

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
Published on: August 8, 2019
Changes in mood, fatigue, sleep, cognitive performance and stress hormones among instructors conducting stressful
Oshin Vartanian1, Brenda Fraser2, Doug Saunders2
1Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada.
Abstract:
Numerous studies have examined the effects of captivity survival training on psychological and physiological function in trainees. In the present study we shifted the focus to instructors, and measured the effects that the delivery of training exerts on their levels of stress and performance. Because instructors are called upon to perform difficult duties (e.g., mock interrogations) under extreme conditions, we hypothesized that significant increases in psychological and physiological indices of stress would occur due to training. In addition, as part of their job tasking, the instructors conducted courses in consecutive weeks. This offered a unique and ecologically valid opportunity to assess carryover of stress from one week to the next. We hypothesized stress levels would be higher in the second than the first week of training. Our first hypothesis was supported: Delivering training was associated with impairments in mood, fatigue, and sleep, as well as a reduction in the ratio of testosterone/cortisol level in blood. Our second hypothesis was largely not supported as a 3-day break separating consecutive courses appeared sufficient for restoring psychological and physiological function. Our results demonstrate that although the delivery of training exerts negative effects on instructors' levels of stress, the 3-day recovery period separating consecutive courses is sufficient to return psychological and physiological function to baseline levels.
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