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  • Writer's pictureSleep Well Blog

When shift work goes against your chronotype

Updated: Oct 18, 2019

While I would probably say that if I were working the night shift, I would be very happy, I think some regular readers may realise that this is because of my chronotype. A chronotype is the "behavioural manifestation of underlying circadian rhythms of myriad physical processes" as per Wikipedia ( -- basically, it just means that you are wired somewhere along the scale of being a morning or an evening person.

However, whereas I am a true night owl, I know that many night-shift workers remain awake at night solely because their jobs demand it. These people end up experiencing the social jet lag that evening types experience when trying to adapt to a 9-to-5 lifestyle, except that morning people are trying to adapt to working overnight instead. This is extremely challenging, health-wise, because our respective chronotypes, which determine when we sleep and wake as well as other things like when we get hungry, for instance, are hardwired in us, and health consequences associated with going against our type exist. What adds to the complexity of this situation is that some people have shifts that rotate. Therefore, not only must they go against their bodies' circadian rhythms, they also experience no consistency in their bedtimes.

Research is mixed as to which situation is worse. In either case, your body just can't catch a break. Imagine what this does to your health in the long term. It is no wonder, then, that shift work (if going against your circadian rhythm) is considered a probable carcinogen by the World Health Organization (

Further, for some people, their sleep troubles have become so severe that they are deemed to have a circadian disorder, which is referred to as shift work sleep disorder (SWSD). Essentially, SWSD is caused by the mismatch between one's circadian rhythm and one's work schedule, where the adjustment to the work schedule is particularly challenging for that person. When someone has shift work sleep disorder, that person is simply unable to adjust well to scheduled work hours. Perhaps, it would be more accurate to say that a person who presents with SWSD is one whose adjustment to shift work is worse relative to others who appear to handle shift work relatively better, even though these people are likely experiencing the effects of social jet lag.

To be diagnosed with this particular circadian disorder, a person must be unable to overcome the experience of excessive sleepiness and fatigue during their shift-work hours. I have a link for you if you would like to read more about SWSD:

Here is an excerpt from the abstract of that journal article:

"Approximately 10% of shift workers suffer from this disorder, which seriously impairs their ability to function. Shift work disorder is associated with increased risk of gastrointestinal problems, cancer, depression, heart disease, excessive sleepiness and accidents, and decreased productivity."

Kind of bleak, wouldn't you say?

It's not an easy situation to be in when you have to decide between your livelihood and your health. I know, for me, my "shift work" was that of having a 9-to-5 job and working at a time when I should have been sleeping, as per my circadian rhythm. Obviously, I found this extremely challenging. In the end, I decided to make sure that my lifestyle aligned with my body clock.

The day may come when this issue of working against our circadian rhythms will be resolved, thereby lowering health risks. In the meantime, awareness and education is key.

If you are a shift worker, what are your thoughts on this? How are you managing your sleep, especially if you are on a rotating schedule? Moreover, were you aware that there was even such a thing as shift work sleep disorder, or is this the first time that you have come across this term?

Message us through this blog or via Facebook. We would really like to hear your thoughts on this issue, and please share this entry, if you think more people should know about shift work and sleep.


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