You’re probably familiar with Benjamin Franklin’s famous saying: “Early to bed and early to rise, makes a man healthy, wealthy, and wise.”
But less well known is a quote from English poet William Blake: “Think in the morning. Act in the noon. Eat in the evening. Sleep in the night.”
Unfortunately, if you work the night shift, you can’t take the good advice of these great men. Which means night shift workers and others who don’t follow a normal nighttime sleep pattern are subject to disrupted circadian rhythms. Even a small disruption in sleep can lead to a large disruption in your genes, which potentially leads to cancer.
Read on to learn how your sleep patterns connect to cancer risk, and what you can do about it if a regular sleep schedule just isn’t possible.
Circadian rhythms and cancer
Your circadian rhythm is the 24-hour rhythmic output of your human biological clock. Shift workers don’t follow the body’s natural clock, because their work schedule is outside of the typical 9-to-5 pattern.
According to the Bureau of Labor Statistics, millions of Americans are considered shift workers. They include doctors and nurses, air traffic controllers, pilots, police officers, commercial drivers, customer service reps… and the list goes on. Shift work schedules are defined as rotating shifts, early-morning and late-night shifts, or overnight shifts.
Why is there so much shift work in the first place? It seems the new demands of 24-hour culture, along with globalization, make it essential. Sadly, any advantages gained in productivity are hijacked by health concerns.
A study from the University of Surrey, UK, published earlier this year in the journal Proceedings of the National Academy of Sciences, found that the daily rhythms of our genes are completely thrown off when we shift our sleeping timeframes. The upset leads to illness and potentially to cancer.
The study itself included several participants who followed a 28-hour day cycle without any natural sunlight or darkness. After six days, the study participants were on a sleep schedule that was 12 hours off from normal – effectively meaning they slept during the normal daytime hours.
At that point, researchers went in and collected blood samples from each participant to measure gene expression. They found a six-fold reduction in the number of genes that displayed a 24-hour rhythm (meaning over 700 genes were affected).
Researchers don’t completely understand the role of each and every gene, but they do know that several of the affected genes play a role in transcription and translation, which equals a widespread disruption to several biological processes.
One of the study’s co-authors, Dr. Simon Archer, said, “Over 97% of rhythmic genes become out of sync with mistimed sleep and this really explains why we feel so bad during jet lag, or if we have to work irregular shifts.”
And let me add that, yes, genetic damage still matters even in light of new findings that damage to mitochondria is what drives cancer. The same forces that damage genes are thought to damage mitochondria. We’re still far from knowing the full story on the interactions between genes and mitochondria.
Sleep disturbance leads to
loads of other problems
This isn’t the first study to point to cancer as a health risk of sleep deprivation and interrupted sleep. Other studies have shown that women who work at night, for example, have an increased risk of breast cancer and possibly colorectal cancer. Scientists believe the disruption in circadian rhythm changes a woman’s normal nighttime production of melatonin and reproductive hormones. Similar evidence suggests that men with altered sleep schedules seem to be at higher risk for prostate cancer.
Cancer isn’t the only health risk of long-term circadian disruption. A regular interruption to your circadian rhythm also puts you at greater risk for illnesses like heart disease, gastrointestinal disorders, frequent infections, obesity, and an increased incidence of colds and flu. And, it can lead to irritability and depression, as well as challenges in your personal relationships (because you’re generally tired and crabby).
Health problems aren’t the only negative effect of sleep disturbance. Shift workers faced with regular sleep disturbance frequently fight fatigue in the workplace, which can lead to accidents, injuries, and even fatalities – especially when you consider that shift workers usually fill the most dangerous jobs, like law enforcement, emergency medical services, security, and so forth.
When regular sleep isn’t an option, do this
The only truly effective treatment for circadian rhythm sleep disorder is to get more sleep, and to do it on a regular, 24-hour schedule.
But if you’re tied to a disturbed sleep schedule due to your profession or other reasons, you can lessen the effects of the disorder by attempting short naps throughout your shift and doing your best to make up for your sleep deficit during your hours off.
Sleep during the day can be improved by wearing eye masks or hanging up blackout blinds in your room, along with using either a white noise machine or earplugs. Also, stick to the same bedtime and wakeup schedule, even on your days off.
Other interventions are bright light therapy, where you use artificial light at certain times during the day to help reinforce your body clock into adapting to your new time zone. Your doctor might also prescribe a sleeping pill to help you rest, but these often lead to a tolerance or a dependency, so I don’t recommend them.
A melatonin supplement may help if you take it several hours before you plan to sleep. Melatonin is a natural hormone made by your brain’s pineal gland that signals your body when it’s time to sleep.
Also of concern are people who work normal daytime hours but still stay up much of the night watching television or working/playing on a computer. It’s a mistake to even allow light in your bedroom at night. You should try to spend eight or nine hours in total darkness, sleeping.
All of which is a good reminder that health requires some effort. It doesn’t just drop from the sky. Eating right, of course, is one of the most important factors, and our last issue discussed a food you definitely want to avoid. If you missed the story, click here.
Lee Euler, Publisher
“Breast cancer and circadian disruption from electric lighting in the modern world.” By Richard G. Stevens, et al. A Cancer Journal for Clinicians. 24 Dec 2013 DOI: 10.3322/caac.21218. http://onlinelibrary.wiley.com/doi/10.3322/caac.21218/full
“Circadian disruption and breast cancer: from melatonin to clock genes.” By Stevens, R.G. Epidemiology. 2005 Mar;16(2):254-8. http://www.ncbi.nlm.nih.gov/pubmed/15703542
“Circadian disruption, shift work and the risk of cancer: a summary of the evidence and studies in Seattle.” By Davis, S., and Mirick, D.K. Cancer Causes Control. 2006 May;17(4):539-45. http://www.ncbi.nlm.nih.gov/pubmed/16596308
“Daily rhythms of our genes are disrupted when sleep times shift.” Sourced from the University of Surrey, 20 January 2014. http://www.sciencedaily.com/releases/2014/01/140120173334.htm
“Disrupted Sleep Schedule Affects Genes’ Circadian Rhythms, Study Finds.” Huffington Post: Healthy Living: 23 January 2014. http://www.huffingtonpost.com/2014/01/23/sleep-genes-circadian-rhythms_n_4639339.html
“Shift Work and Sleep.” National Sleep Foundation: Retrieved 22 July 2014. http://sleepfoundation.org/sleep-topics/shift-work-and-sleep
“Shift Work – Overview.” SleepEducation.com: Retrieved 22 July 2014. http://www.sleepeducation.com/sleep-disorders/shift-work/overview
“Sleep Deprivation Can Change Your Genes.” Huffington Post: Healthy Living: 26 February 2013. http://www.huffingtonpost.com/2013/02/26/sleep-deprivation-genes_n_2766341.html