News Article / February 25, 2014
by Lieutenant Irina Jakhovets
Canadian Forces Station Alert, located on the northern tip of Ellesmere Island, is the perfect place to study the effects of round-the-clock darkness on sleep habits and circadian rhythms. From mid-October to late February the sun does not rise above the horizon at this most northerly, permanently inhabited location in the world, and total darkness lasts from the end of October to mid-February.
On January 14, 2014, Defence Research and Development Canada (DRDC) personnel arrived at CFS Alert – during the 24-hour darkness period – to gather data for their Arctic Circadian Rhythm Sleep Study.
Thirteen Canadian Armed Forces members volunteered to participate in the three-week study. The participants were required to wear an ActiGraph watch and record data about their sleep habits in a log book every day for the duration of the study. They also had to participate in two 24-hour melatonin data collection sessions.
After a week of getting used to a bulky ActiGraph watch, and remembering to complete the daily log, the volunteers participated in their first melatonin data collection.
Melatonin is a hormone produced by our body that acts as a regulator of the sleep/wake cycle. CFS Alert’s 24-hour darkness period in the winter time makes it the perfect place for such a study.
While it is known that disruptions to circadian rhythms can have an adverse effect on performance, the specific nature of the disruptions caused by continual darkness are less well understood. The scientists planned to investigate the effect of 24 hour darkness on people’s circadian rhythm and sleep habits and then develop and evaluate the effectiveness of individualized treatments to correct the disruptions.
At 8:30 a.m. on Saturday, January 18, 13 lounge chairs were set up in the main gymnasium while the DRDC staff awaited the arrival of the subjects.
The participants were sequestered for 24 hours in a dark gym, lit only by coloured Christmas lights and a big projection screen.. As light affects melatonin production, the subjects were not allowed to use any electronic devices or be exposed to light levels above five lux.
Lux is the unit of measurement used to describe the intensity of light. For instance, a full moon on a dark night measures about 0.27 to one lux, office lighting measures about 320 to 500 lux and full daylight, but not direct sunlight, measures about 10,000 to 25,000 lux.
The participants found that staying awake during the day was the real challenge since they were only allowed to sleep between 11 p.m. and 7 a.m. the next morning. They also had to provide saliva samples every two hours; this consisted of chewing on a cotton swap for 45 seconds and then letting it sit in their mouths to absorb the saliva for an additional 45 seconds. At 11 p.m., the participants were allowed to go to bed, but they were wakened every hour and 40 minutes for the next sample.
Once all the samples had been compiled and analysed, members were told about their results. Everyone was anxious to know if they would require treatment or not.
The treatment consisted of wearing a visor with an 8,000 lux green light shining into their eyes. Essentially, this was a portable sun lamp that would help decrease inopportune melatonin production, and help the participants realign their sleep patterns.
Eight of the 13 participants needed light treatments and were affectionately nicknamed ‘aliens’ because of their green glowing eyes. The other five became the control group.
The second 24-hour data collection, which studied responses to the light therapy treatment, occurred after ten days of treatment.
The process was the same as it had been the previous Saturday. Once all data was collected and analysed, members were again given their melatonin profile and were finally able to remove their ActiGraph watch.
The preliminary results showed that there was some improvement in the circadian rhythms of the treatment group, although, at the time this article was written, the final results were pending.
DRDC staff plan to return to CFS Alert in June to complete the same protocol during the 24-hour sunlight period to see what effect 24 hours of light has on circadian rhythm compared to 24 hours of darkness.
While those of us stationed at CFS Alert may not miss the ‘aliens’ walking around the station, we look forward to the impact these studies will have on managing the sleep pattern changes seen up here in CFS Alert, as well as across the Canadian North.