I used to think that night shift wasn’t that big of a deal. In fact, I had many “good reasons” for working late at the psychiatric hospital. It was calmer than the day-shift, I made extra money, and I liked the relaxed vibe I had with my co-workers. But many years later and quite a bit of reflection, I realized how damaging that time of my life was to my body and mind.
I ate cookies and cake during the night when I was bored, I was isolated from my friends who worked normal hours, I barely had the energy to workout (and consequently gained 15 pounds), and most importantly, I felt very unhappy. It wasn’t until I quit that job and started looking at the research, that I realized I was falling apart because of my unbalanced sleep schedule. Come to find out, night shift disrupts our natural circadian rhythm leading increased risk of disease, obesity, diabetes, fatigue, sleep disturbances, and overall well-being.
In this blog post, I’ll discuss the basics of circadian biology, the harmful effects of disrupted circadian rhythms, and possible remedies if you’re stuck in shift work.
How our Circadian System Works:
We have a central control unit in our brain that’s called our Master Circadian Clock (or the Suprachiasmatic Nucleus, SCN). The Master Circadian Clock has a direct connection to the organs of our body, our hormone system, and our autonomic nervous system (1). This Master Clock produces melatonin, which increases at night to tell us that it’s time to sleep. Our Master Clock is controlled by the day and night cycles, if we’re fasting or eating, and if we’re asleep or awake. This Master Clock also produces our circadian rhythms.
We also have other biological clocks in our peripheral organs and they receive signals from the Master Circadian Clock via neural, humoral, and temperature signals. This means, our organs, our brain chemicals, and even some products of metabolism have their own rhythms that are synced up to our Master Clock. These clocks run in parallel with our Master Clock.
And, we want these clocks (master clock and peripheral clocks) to be in alignment!!
When our peripheral clocks our misaligned (running too fast or too slow) they can disrupt our circadian rhythms, which is when all the problems occur.
Harmful Effects of Night Shift:
Night shift has been linked to cancer
In 2007, the International Agency for Research on Cancer (IARC) classified shift work with circadian disruption as a probable human carcinogen. One agent from IARC, stated that shift work was more worrisome than some carcinogenic chemicals!
Night shift is associated with depression and interferes with levels of brain chemicals
Researchers found that shift workers in all occupational groups had an increase risk of depression; however, there was a lack of statistical confirmation (3).
Brain monoamines (noradrenaline, dopamine, and serotonin) have been shown in rats to be off-balance with irregular light-dark cycle leading to anxious behavior. This highlights the possible connection between circadian disruption and anxious or depressed behavior influenced and controlled by the neurotransmitter systems. (4)
Night shift is associated with cardiovascular disease mortality and disrupts metabolites of metabolism
Night shift sleep patterns have been shown to impact digestive organs, the liver, and the pancreas. Because night shift worker’s circadian clocks are not aligned with the Master Circadian Clock, there is major disruption in metabolism. This insight leads to possible lifestyle changes that can benefit someone experiencing digestive problems such as stomach aches, indigestion, or irregular bowel movements. (5)
Researchers have found that nurses working night shift for 5 years had a moderate increase in all-cause and cardiovascular disease mortality, emphasizing the detrimental impact on the circulatory system. (6)
If you can’t change your schedule, what can you do?
Currently there isn’t enough research to determine a complete remedy for night shift work, but here are some suggestions that may be useful if you can’t change your circumstances.
Mindfully eating and drinking while at work.
Notice if you’re snacking when you’re bored at work. Are you grabbing for candy or treats because there’s not much else to do? Are you drinking sodas or caffeine to stay awake all night? Try switching your sodas for herbal teas to eliminate the extra sugar and empty calories.
Keep a consistent eating schedule.
Similar to the mindful eating practice, try to maintain an eating schedule on night shift, even if you’re used to eating all night. Try having your breakfast when you wake up in the afternoon (1-3PM), your lunch at 8-9PM, fast throughout your night shift, and then have your “dinner” at the completion of your night shift. There aren’t many resources to support my hypothesis on this food timing schedule, but it makes sense that fasting through the night is the closest thing to a regular eating pattern that you can manage.
In one research review, the suggestion for shift workers to block their eyes from the light spectrum was mentioned as a way of protecting their hormonal system (2). However, this may or may not have consequences on the worker’s attention and focus. This tip may not be possible for shift workers in the healthcare system, like nurses or doctors.
Find a therapist.
This may seem dramatic compared to the previous tips, but this is a serious issue. It’s so serious that even German law gives shift workers free occupational medicine exams and counseling before starting shift work AND once every 3 years. This is due to the fact that depression is not uncommon amongst shift workers, and therapy can be of benefit to those feeling down.
Thanks for reading. If you have any questions or would like more information on ways to improve your nutrition or lifestyle as a night shift worker or someone dealing with disrupted sleep, email me and let’s talk!
(1)Buijs RM, van Eden CG, Goncharuk VD, Kalsbeek A. The biological clock tunes the organs of the body: timing by hormones and the autonomic nervous system. The Journal Of Endocrinology. 2003;177(1):17-26. https://uws.idm.oclc.org/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=mdc&AN=12697033&site=eds-live&scope=site. Accessed April 1, 2019.
(2)Erren TC, Falaturi P, Morfeld P, Knauth P, Reiter RJ, Piekarski C. Shift work and cancer: the evidence and the challenge. Dtsch Arztebl Int. 2010;107(38):657–662. doi:10.3238/arztebl.2010.0657
(3)Angerer P, Schmook R, Elfantel I, Li J. Night Work and the Risk of Depression. Dtsch Arztebl Int. 2017;114(24):404–411. doi:10.3238/arztebl.2017.0404
(4)Matsumura T, Nakagawa H, Suzuki K, Ninomiya C, Ishiwata T. Influence of circadian disruption on neurotransmitter levels, physiological indexes, and behaviour in rats. Chronobiology International: The Journal of Biological & Medical Rhythm Research. 2015;32(10):1449-1457. https://uws.idm.oclc.org/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=s3h&AN=111870548&site=eds-live&scope=site. Accessed April 1, 2019.
(5) Skene DJ, Skomyakov E, Chowdhury NR, et al. Separation of circadian- and behavior-driven metabolite rhythms in humans provides a window on peripheral oscillators and metabolism. Proceedings of the National Academy of Sciences of the United States. 2018;(30):7825. doi:10.1073/pnas.1801183115.
(6)Fangyi Gu MD, ScD, Jiali Han, PhD, Francine Laden, ScD, An Pan, PhD, Neil E. Caporaso, MD, Meir J. Stampfer, MD, DrPH, Ichiro Kawachi, MD, PhD, Kathryn M. Rexrode, MD, MPH, Walter C. Willett, MD, DrPH, Susan E. Hankinson, ScD, Frank Speizer, MD, and Eva S. Schernhammer, MD, DrPH. Total and Cause-Specific Mortality of U.S. Nurses Working Rotating Night Shifts. American Journal of Preventive Medicine, March 2015 DOI: 10.1016/j.amepre.2014.10.018