Bright lights and long flights

Bright light - particularly blue light at around 460nm - is known to improve alertness and cognitive function which is why it's a convenient way of helping you to focus and crack on at work. It's also used to realign circadian rhythms of jet-lagged travellers and night shift workers. With all this in mind, there would seem to be great potential for light therapy in helping flight crew cope with demanding long-haul schedules. A preliminary study just published is the first to investigate just that, using portable blue light therapy to keep the crew feeling alert and awake (read the full abstract).

Photo © 2010 J.Ronald Lee.

Pilots and cabin crew were involved in the month-long trial at the College of Aviation, West Michigan University. They all wore actigraph bands throughout to monitor their sleep and wake activity and each day completed questionnaires to assess alertness/fatigue and visual psychomotor vigilance tests (PVT). After two weeks of baseline monitoring, the next two weeks included 30 minutes blue light therapy per day (using a small LED device, similar to Zest) as well as the questionnaire and tests - these were both accessed via a smartphone app so the study could be carried out whilst the crew were airbourne.

Though cabin crew and pilots were shown to have baseline differences (e.g. cabin crew started the trial registering higher sleepiness scores than the pilots) all 14 crew members that took part showed significant differences with and without light therapy. Ratings for alertness and sleepiness (as assessed by the questionnaire) both improved significantly with light therapy. There were two aspects to the PVT: the number of 'lapses' (when crew took longer than 500 milliseconds to tap a target on their phone screen) decreased; in addition reaction times improved after light therapy, particularly amongst cabin crew. Again, the pilots differed in that they had faster reaction times to start with so, although they also improved, the change was relatively modest.

The researchers admit that further studies need to be done but suggest that light therapy is a positive step to counteracting fatigue for flight crew and boosting on-the-job alertness: "A review of literature and results of this study show the acute alerting effect of blue light to be a potentially useful countermeasure to reduce physiological, perceived, and cognitive fatigue, where conditions allow its use. Results garnered can be used to develop innovative light therapies and preventive strategies for industries with shift workers such as aviation, maritime, rail, nuclear and medical."

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