Medically Reviewed by Donny Huynh, MD

From cigarettes to asbestos — of all the many things we face in life that are related to cancer, who would have guessed that lack of sleep might sit on that list.

“Although more research is needed, a number of studies point to a link between shift work or general lack of sleep and cancer,” says McLeod Cancer Specialist Donny Huynh, MD. “One researcher even called lack of sleep a public health hazard that might lead to obesity, diabetes and heart disease, as well as cancer.”

Lack of sleep and light at night seem to suppress the production of melatonin. Melatonin could increase the release of estrogen in women. In both men and women, inhibited melatonin production can spark genetic mutations, reduce DNA repair and suppress a person’s immune system.

Statistics from several studies point to a connection (although not necessarily cause and effect) between night work or lack of sleep and cancer:

• More than one study points to increased risk for lung and colorectal cancers.
• In post-menopausal breast cancer patients, lack of sleep may cause more aggressive recurrent tumors.
• Fatal prostate cancer in men under the age of 65 is associated with males who sleep less. There was a 55% greater risk of dying from prostate cancer for men, who only have 3-5 hours sleep a night. Men, who reported 6 hours of sleep a night, had a 29% higher risk than men, who reported 7 hours of sleep a night.
• In general, men who worked nights reported an increased risk of prostate cancer.
• Women, who worked night shifts, reported a 30% higher rate of breast cancer.

ACTION YOU CAN TAKE TO HELP YOU SLEEP
Numerous sources list some or all of these ideas to help you get to sleep and stay asleep at night:

• Develop a bedtime routine – reading a book, taking a warm bath, listening to calming music.
• Go to bed at the same time every day.
• Keep your bedroom at a comfortable temperature – probably less than 70 degrees.
• Steer clear of alcohol and heavy meals before bedtime.
• Avoid caffeine (coffee, tea, soda and chocolate) in the evening.
• If you exercise, try not to do it within 3 hours of bedtime.

In today’s work, here may be some of the most difficult advice to adhere to:

• Avoid watching TV or using your computer, tablet or phone just before bed. These devices emit so-called “blue light.” This type of light tricks your body into thinking it’s daytime. If you must use these devices, wear glasses that block blue light or you can download an app, such as Night Shift of f.lux from the iPhone or Android store to block blue light from your device.

Have a question?  Ask a Cancer Specialist.

Sources include: McLeod Health, Journal of Cancer, Sleep Foundation, Breast Cancer Research & Treatment, Environmental Health Perspectives, American Association of Cancer Research, US Dept. of Health & Human Services