Sleeping Well

Are you a health professional?

This section does not replicate the other information on this topic but provides additional details or context most relevant to professionals.

Clinical practice guidelines

The 2020 NCCN survivorship care guidelines recommend ensuring an adequate amount of sleep. Registration is required for access.

Counseling patients

If you don’t already inquire regularly about your patients’ sleep durations and schedules, you may want to consider making this a part of your routine topics to discuss. As we’ve detailed within this topic, sleep time and quality are both indicators of and contributors to many other health issues and overall well-being.

Modes of action: cortisol, sleep and cancer

Cancer incidence, progression and mortality are linked to stress and disruption of the circadian rest and activity cycle. Cortisol, our primary stress hormone, helps regulate the sleep-wake cycle. Activation of the processes that produce cortisol (the hypothalamic-pituitary-adrenal (HPA) axis) can lead to arousal and sleeplessness.¹Nicolaides NC, Vgontzas AN et al, editors. HPA axis and sleep. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000–.

Although the mechanisms are not fully understood, high cortisol levels and disrupted sleep-wake cycles are connected to these outcomes:²Berger AM, Farr L. The influence of daytime inactivity and nighttime restlessness on cancer-related fatigue. Oncology Nursing Forum 1999; 26(10):1663-71; Block KI. Life over Cancer: The Block Center Program for Integrative Cancer Care. New York: Bantam Dell. 2009. pp. 412-414.

Cortisol in excess may push several cancer processes forward, especially metastasis. A rise in blood cortisol in response to stress or poor sleep quality can speed up tumor growth. Cortisol suppresses immunity which may have a negative influence on recurrence risk.³Randall M. The physiology of stress: cortisol and the hypothalamic-pituitary-adrenal axis. Dartmouth Undergraduate Journal of Science. 2010 Fall. February 3, 2011. Viewed February 20, 2022.

The combination of cortisol and adrenaline increases blood glucose levels. Chronic high blood glucose episodes can be a direct or indirect mediator of the increase in tumor cell growth.⁴Ryu TY, Park J, Scherer PE. Hyperglycemia as a risk factor for cancer progression. Diabetes & Metabolism Journal. 2014 Oct;38(5):330-6. Cortisol also increases insulin resistance and seems to stimulate the ability of some cancer cells to grow and metastasize.⁵ Block KI. Life over Cancer: The Block Center Program for Integrative Cancer Care. New York: Bantam Dell. 2009. p. 411; Moreno-Smith M, Lutgendorf SK, Sood AK. Impact of stress on cancer metastasis. Future Oncology. 2010 Dec; 6(12):1863-1881; Andrews RC, Walker BR. Glucocorticoids and insulin resistance: old hormones, new targets. Clinical Science (London, England). 1999 May;96(5):513-23.

Studies have investigated cancer outcomes related to cortisol and sleep disruption:

• Breast cancer patients who don’t have normal cortisol rhythms have less-active natural killer cells and have reduced survival compared to others.⁶Sephton SE, Sapolsky RM, Kraemer HC, Spiegel D. Diurnal cortisol rhythm as a predictor of breast cancer survival. Journal of the National Cancer Institute. 2000;92(12):994-1000; Andersen BL, Farrar WB et al. Stress and immune responses after surgical treatment for regional breast cancer. Journal of the National Cancer Institute. 1998 Jan 7;90(1):30-6.
• In adults with cardiovascular and cerebrovascular diseases, sleeping less than 6 hours a night is associated with almost triple the risk of cancer mortality compared with sleeping 6 or more hours a night.⁷Fernandez-Mendoza J, He F, Vgontzas AN, Liao D, Bixler EO. Interplay of objective sleep duration and cardiovascular and cerebrovascular diseases on cause-specific mortality. Journal of the American Heart Association. 2019 Oct 15;8(20):e013043.

Fortunately, improving sleep can block this cascade of effects. Sleep, and especially deep sleep, inhibits the HPA axis that produces cortisol.⁸Nicolaides NC, Vgontzas AN et al, editors. HPA axis and sleep. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000–. Further, melatonin, the “sleep hormone”, promotes sleep. It is a powerful antioxidant and exerts “protective effects against oxidative stress,  abnormal immune activation and/or inflammation, obesity, cardiovascular disorders, cancer development, and neurodegeneration.”⁹Ferlazzo N, Andolina G et al. Is melatonin the cornucopia of the 21st century? Antioxidants (Basel). 2020 Nov 5;9(11):1088. Melatonin is also instrumental in eliminating cancer cells and reducing the side effects of chemotherapy.¹⁰Winters N, Higgins Kelley J. The Metabolic Approach to Cancer: Integrating Deep Nutrition, the Ketogenic Diet, and Nontoxic Bio-Individualized Therapies. Vermont: Chelsea Green Publishing. 2017. p. 252. Promoting optimal melatonin and cortisol cycles can bring many benefits.