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Updated: Jun 19, 2026

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
Published on: August 8, 2019
Subjective and objective sleep in relation to the work context, profession, age, and workload among helicopter
Tine Almenning Flaa1,2,3, Erik Zakariassen1,2,4, Bjørn Bjorvatn2,5
1Department of Research and Development, The Norwegian Air Ambulance Foundation, Oslo, Norway.
Abstract:
Sleep is essential for cognitive function and performance. This is particularly evident in safety-critical professions such as Helicopter Emergency Medical Services (HEMS). The present study examined sleep among pilots and HEMS crew members (HCMs) during a 7-day duty period. Based on sleep diary and actigraphy, we assessed sleep in relation to work context, profession, age, and workload. Sleep diary data showed delayed sleep timing across the week, with reduced sleep duration (08:22 vs. 07:48, b = -0.55, p < 0.05) and increased sleep debt (-00:03 vs. 00:27, b = 0.57, p < 0.05) from first to last duty day. Furthermore, pilots went to bed later (00:38) than HCMs (00:19, b = 0.38, p < 0.05). Night missions were associated with reduced sleep duration (06:52 vs. 07:29, b = -0.52) and sleep efficiency (80% vs. 92%, b = -14.8), as well as increased wake time after sleep onset (01:26 vs. 00:11, b = 86.3) and sleep debt (00:29 vs. 00:01, b = 0.44), all p < 0.05. Older workers at busy bases accumulated more self-reported sleep debt (b = 0.86, p < 0.05). These findings highlight how operational demands and worker characteristics influence sleep among HEMS personnel, underscoring the need for strategies to optimize sleep.
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