How does blue light influence the shift workers?

One doesn’t have to be working in a hospital, in the world of gastronomy, or in transport to know what shift work means. It is always very tiring to change your daily schedule a few times a week. It does not only destroy our plans but also our health. 

Obviously shift working is not the ideal work pattern, one that we would gladly choose, but sometimes it happens that it is the only way our team can meet their deadline. What can we, and all the people working as doctors, nurses, lawyers, cooks, waiters, and numerous other professions do about it? 

Well, we could let our circadian rhythm go crazy and then try to go back to normal over the next month (because that's the most commonly quoted time-period our body needs to get back to the way it was, before we started working at night and sleeping during the day, even for just a few days). But, if we consider shift work for longer than just a few days, the option mentioned above can never be enough. 

While looking through medical articles that consider bright light therapy, it is apparent the great majority treat light not as a whole, but as a bunch of different colors (a different color is attached to a different frequency of lightwave) combined together to produce white light.  There are now more and more theories that it is the blue light (the blue portion of white light) that is not only responsible for waking us up in the morning, but also for preventing us from falling asleep in the evening after long hours spent in front of the computer or on our mobile. If this is true, why not expose ourselves to blue light in the evening and at night while working in shifts, to keep us more alert, and then block the exposure to this part of white light during the day, to help us fall asleep before going back on the night shift? 

An interesting experiment was conducted by Sasseville and Hebert on a group of volunteer shift workers.  Based on a study by Bjorvatn and Pallessen in 2008, which clearly stated that ‘modification of the light/dark cycle with artificial light at night and a fixed period in a dark bedroom, combined with the use of dark glasses when outdoors, has been shown to facilitate adaptation to night shifts in real work settings’, Sasseville and Hebert further examined the conditions and outcomes of the 2008 findings. The main reason for doing so was to examine the theory that bright light exposure at night is likely to cause transient eye discomfort and headaches. Sasseville and Hebert decided to use auxiliary blue-green light at night, combined with wearing blue-blocking glasses during the day in a real workplace, and evaluate both performance and circadian rhythm adaptation. 

The results were promising: ¾ of their study group slept significantly better, experiencing shorter sleep latency and fewer difficulties initiating and maintaining sleep. Total sleep time was also shorter, implying that they tended to be less tired over the course of the study. 

The one thing that needs to be taken into consideration when evaluating this study, is that the study group consisted of 4 men who were in good health; non- smokers, taking no medicines and not traveling through more than two time zones in the month prior to the study. Although this study group may not be persuasive for many people, the results were scrupulously analyzed and can therefore surely be the basis for further studies of this technology in the future.

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