In my book, The Layman’s Guide To Surviving Cancer, I discuss the link between sleep and cancer progression and healing (“To Sleep, Perchance to Dream (About Being Healthy),” pp. 98-102). I address in that section several studies linking insufficient or disrupted sleep patterns and abnormalities in one’s circadian clock with the development and progression of cancer, and how to achieve better sleep patterns during (and after) cancer treatment. A recent meta-analysis (a review of previous studies on the topic) confirms that link.
In “Circadian Disrupting Exposures and Breast Cancer Risk: A Meta-Analysis” (International Archives of Occupational and Environmental Health, September 2014), researchers at the University of Georgia analyzed the findings of 28 prior studies investigating the link between circadian disruption and breast cancer. Their study indicates that disrupted or abnormal sleep patterns are associated with a higher risk of breast cancer, with the highest risk being found among patients who experience exposure to light at night (thereby confirming prior research indicating that the best, healthiest environment for sleep is a completely dark room). This may be because interrupted sleep results in a lower production of melatonin (which has antioxidant effects), thereby resulting in increased estrogen production, which in turn has been linked to a higher incidence of breast cancer.
An abstract of this study can be found at http://link.springer.com/article/10.1007%2Fs00420-014-0986-x. Check it out, along with the discussion of this issue in my book, and let me know what you think. Sleep tight!
In healing,
Howard
