Circadian countermeasures in the high Arctic during winter


  1. Paul, M.A.
  2. Love, R.J.
  3. Hawton, A.M.
  4. McCreary, D.R.
  5. Brett, K.D.
  6. Jerrott, M.J.
  7. Arendt, J.
Corporate Authors
Defence Research and Development Canada, Toronto Research Centre , Toronto ON (CAN)
Background. DRDC Toronto has optimized the ability to manipulate circadian rhythms with supplementary melatonin and/or light treatment, as appropriate, to reduce or eliminate the circadian desynchrony that is inherent in jetlag and shiftlag. For the past 3 years we have collected Arctic circadian baselines at CFS Alert to establish the impact on human circadian physiology during each of the extremes of arctic winter and arctic summer photoperiod. The work described herein is our first attempt at implementing Arctic circadian countermeasures for the treatment of discordant human circadian rhythms that are apparent in personnel of CFS Alert during the Arctic winter. Methods. This data collection commenced on Jan 18, 2014 at CFS Alert. To qualify for the study, subjects had to have been at Alert for at least three weeks prior to commencement of the study. Subjects filled out questionnaires regarding sleep difficulty and psychosocial parameters, and wore motion logging devices (Actigraphs) to obtain objective sleep data. Saliva was collected at regular intervals on two occasions, two weeks apart, to measure melatonin and assess melatonin onset. Individuals with a melatonin rhythm that was in disaccord with their sleep schedule were given a light treatment visor to use daily. Treatment efficacy was evaluated using the questionnaire data, actigraphic data, and endogenous melatonin profiles. Results. The light treatment prescribed to eight of the thirteen subjects was effective, to

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endogenous melatonin;circadian desynchrony;fatigue;sleep hygiene;modeled cognitive effectiveness
Report Number
DRDC-RDDC-2014-R42 — Scientific Report
Date of publication
01 Aug 2014
Number of Pages
Electronic Document(PDF)

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