We know that cancer is a major burden on public health not only in this country, but worldwide. And unfortunately, it is projected to only get worse over time.
So… how does sleep fit into this picture??
Well, there is research about sleep and overall health. And we definitely need more research in regards to cancer and sleep, but it has been found that sleeping problems may be a risk factor for developing certain types of cancer. Sleeping problems my also affect the progression of cancer and even the effectiveness of treatment.
On the other hand, cancer can affect sleep. Whether through symptoms of cancer or side effects of treatment, and this can decrease quality of life. Those in survivorship may continue to deal with long term effects of their treatment that can affect sleep.
No one can say that getting better sleep with eliminate cancer risk, but we C AN say that getting better sleep can help overall health. And improved health does help become a protective factor.
Since sleep plays a central role in health and many bodily systems are affected/influenced by adequate or inadequate sleeping, it is imperative that we get adequate sleep. Systems affected include the immune system, the production and regulation of hormones, metabolism and body weight, how cells function and grow.
Should we focus on sleep duration, sleep quality, or circadian rhythm?
Unfortunately, the research doesn't give us much direction or information. And this could be related to how the information or data is collected and all the many other factors that may or may not be taken into consideration. There is at least one large study has shown that those who sleep less have increase cancer risk (1). There has also been sleep depravation studies in animals that have shown more “wear and tear” on cells (2). This "wear and tear" could potentially lead to DNA damage that could potentially lead to cancer.
Quality matters…. But does it increase the risk of cancer?? More research needs to be done to determine this.
Now circadian rhythm does matter. There is research that is showing that circadian disruption can play a role in the development of cancer. Having circadian disruption can absolutely affect hormone production and metabolism as well as how the immune system functions (3,4). Shift workers (working at night) have shown elevated risk of cancer (5). And circadian disruption has even been labeled by the International Agency for Research on Cancer (IARC) as “probably carcinogenic" (6). Wow!!
Now, because sleep is so important to so many bodily systems (i.e., hormones, metabolism, and inflammation), one could extrapolate that sleep may even affect progression of cancer. More research is definitely needed to prove this.
I see first hand that cancer treatment is a major cause of sleep issues for many patients. Everything from chemotherapy to the medications used to manage side effects, sleep quality, duration and circadian rhythm could be affected.
I think we sometimes forget how important sleep is for our bodies. How much of the growth and repair happens during sleep, how well the immune system functions if we don’t sleep well. And lack of sleep can affect our physical, emotional and mental health leading to poorer quality of life overall.
What can you do?
One of the best things that you can do is focus on sleep hygiene. Starts with your bedroom setting. Is it dark enough? Is the temperature set correctly (not too hot, not too cold)? Do you have daily sleep habits (going to bed and getting up at generally the same time every day)? And are you minimizing the use of screen time (whether with TV or computer/smartphone) one hour prior to bed?
Whether you are undergoing treatment or in the survivorship phase of care sleep is important. Furthermore, focusing on the lifestyle changes that can help include nutrition, exercise, social connection, and stress reduction......which all improve quality of life.
1. von Ruesten, A., Weikert, C., Fietze, I., & Boeing, H. (2012). Association of sleep duration with chronic diseases in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study. PloS one, 7(1), e30972.https://www.ncbi.nlm.nih.gov/pubmed/22295122
2. Everson, C. A., Henchen, C. J., Szabo, A., & Hogg, N. (2014). Cell injury and repair resulting from sleep loss and sleep recovery in laboratory rats. Sleep, 37(12), 1929–1940.https://www.ncbi.nlm.nih.gov/pubmed/25325492
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3. Greene M. W. (2012). Circadian rhythms and tumor growth. Cancer letters, 318(2), 115–123.https://pubmed.ncbi.nlm.nih.gov/22252116/
4. Besedovsky, L., Lange, T., & Haack, M. (2019). The Sleep-Immune Crosstalk in Health and Disease. Physiological reviews, 99(3), 1325–1380.https://www.ncbi.nlm.nih.gov/pubmed/30920354
5. Haus, E. L., & Smolensky, M. H. (2013). Shift work and cancer risk: potential mechanistic roles of circadian disruption, light at night, and sleep deprivation. Sleep medicine reviews, 17(4), 273–284.https://pubmed.ncbi.nlm.nih.gov/23137527/
6. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. (2010). Painting, Firefighting, and Shiftwork. International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, No. 98. 6, Evaluation and Rationale. Available from:https://www.ncbi.nlm.nih.gov/books/NBK326826/