Sleep and Cancer

It is not a new concept that sleep is overall good for your health and promote overall longevity, including cancer. But why is this important? It is estimated in Canada in 2023, that 2 of 5 (40%) Canadians will be diagnosed in their lifetime. (1)

Poor sleep can disrupt our circadian rhythm, alter the immune system, increase inflammation, and even play into the onset and progression of cancer. (2) In an English Longitudinal study of over 10,000 participants over 50 for 8 years, those who had good sleep quality had a lower incidence of cancer, compared to those with poor sleep quality. (3) There may also be an association with sleep duration and colorectal cancer risk and all-cancer mortality. (4) Many studies have also found a correlation between night shift work increasing breast cancer risk, which may be due to the disruption in the circadian rhythm and subsequent changes to hormone production, such as melatonin. (5)

Melatonin, the hormone that helps us fall asleep at night, is released in the absence of light, to help maintain sleep. Hence why it is recommended to avoid screens before bed to allow our bodies to naturally produce melatonin. It is not only beneficial to help with sleep but has numerous studies to counteract many cancer-related side effects such as fatigue, myelosuppression, depression, anxiety, mouth sores and insomnia. In patients with hormone positive breast cancer, melatonin has antiestrogenic effects through interacting with estrogen receptors and inhibiting aromatase activity. (6,7)

Thus, sleep is important in every phase of cancer. Beyond avoiding screens before bed, sleeping in a cool, dark room, no caffeine in the afternoon or large meals before bed may help with sleep. If the basics to help sleep are not improving, it may be time to employ some naturopathic remedies such as melatonin or additional vitamins, minerals, and botanicals.

1. Canadian Cancer Statistics 2023. Published November 2023. Access May 2024.

2. Chen Y, Tan F, Wei L, et al. Sleep duration and the risk of cancer: a systematic review and meta-analysis including dose-response relationship. BMC Cancer. 2018;18(1):1149. Published 2018 Nov 21. doi:10.1186/s12885-018-5025-y

3. Song C, Zhang R, Wang C, et al. Sleep quality and risk of cancer: findings from the English longitudinal study of aging. Sleep. 2021;44(3):zsaa192. doi:10.1093/sleep/zsaa192

4. Li X, Huang D, Liu F, et al. Sleep Characteristics and Cancer-Related Outcomes: An Umbrella Review of Systematic Reviews and Meta-Analyses of Observational Studies. J Clin Med. 2022;11(24):7289. Published 2022 Dec 8. doi:10.3390/jcm11247289

5. Szkiela M, Kusideł E, Makowiec-Dąbrowska T, Kaleta D. How the Intensity of Night Shift Work Affects Breast Cancer Risk. Int J Environ Res Public Health. 2021;18(9):4570. Published 2021 Apr 26. doi:10.3390/ijerph18094570

6. Grant SG, Melan MA, Latimer JJ, Witt-Enderby PA. Melatonin and breast cancer: cellular mechanisms, clinical studies and future perspectives. Expert Rev Mol Med. 2009;11:e5. Published 2009 Feb 5. doi:10.1017/S1462399409000982

7. Sánchez-Barceló EJ, Cos S, Mediavilla D, Martínez-Campa C, González A, Alonso-González C. Melatonin-estrogen interactions in breast cancer. J Pineal Res. 2005;38(4):217-222. doi:10.1111/j.1600-079X.2004.00207.x

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