Light treatment improves sleep quality and negative affectiveness in high arctic residents during winter

Paul, Michel A; Love, Ryan J; Hawton, Andrea; Brett, Kaighley; McCreary, Donald R; Arendt, Josephine

The seasonal extremes of photoperiod in the high Arctic place particular strain on the human circadian system, which leads to trouble sleeping and increased feelings of negative affect in the winter months. To qualify for our study, potential participants had to have been at Canadian Forces Station (CFS) Alert (82° 30' 00 N) for at least 2weeks. Subjects filled out questionnaires regarding sleep difficulty, psychological well-being and mood and wore Actigraphs to obtain objective sleep data. Saliva was collected at regular intervals on two occasions, 2weeks apart, to measure melatonin and assess melatonin onset. Individuals with a melatonin rhythm that was in disaccord with their sleep schedule were given individualized daily light treatment interventions based on their pretreatment salivary melatonin profile. The light treatment prescribed to seven of the twelve subjects was effective in improving sleep quality both subjectively, based on questionnaire results, and objectively, based on the actigraphic data. The treatment also caused a significant reduction in negative affect among the participants. Since the treatment is noninvasive and has minimal associated side effects, our results support the use of the light visors at CFS Alert and other northern outposts during the winter for individuals who are experiencing sleep difficulty or low mood.

2015 Her Majesty the Queen in Right of Canada Photochemistry and Photobiology 2015 The American Society of Photobiology.