We have become a 24-hour society where people can work, shop and exercise at all hours of the day or night. But just because we can, does that mean we should?
Humans evolved in a rhythmic world, with daily and seasonal variations in light, temperature, and food availability. In our modern world we can control all these environmental factors so they are the same throughout the year, but our body is still programmed for circadian variation. Cancer incidence increases when people live out of sync with natural rhythms, like those who do shift work.
Shift Workers at Increased Cancer Risk
Those people who work graveyard shift have an increased risk of breast cancer. This risk increases with the number of years graveyard shift has been done. Getting bright light at night suppresses our natural melatonin surge. Melatonin is a powerful anti-oxidant, protecting our cells from damage.
Shift workers also are at increased risk for:
•Elevated stress hormones
Cancer Causes Sleep Disruption
The sleep – cancer relationship goes both ways. For those people undergoing cancer treatment, sleep disruption can be a symptom. This can be a side-effect of chemotherapy, or of pain, or other factors.
The good news is that several studies have shown that sleep of cancer patients can be improved by doing Cognitive-Behavioral Therapy for Insomnia. Specifically, after treatment, cancer patients ended up sleeping a higher percentage of the time they were in bed, had improved mood, and decreased fatigue. Another study additionally found that the people had fewer nights on medication, and that the improvements were maintained for 12 months afterwards.
High numbers of people in America do shiftwork – 20% of those who are employed. One definition of shiftwork is starting work after 6pm, and before 6am. “Swing shift” which often starts around 3-4pm is also included in some definitions of shiftwork. Whichever definition you use, it is clear that the health of people who do shiftwork suffers.
Shiftworkers experience symptoms such as stomach upset, moodiness, high blood pressure and elevated stress hormones. In the long term these employees also have higher rates of breast and colon cancer in women, and prostate cancer in men. These problems are thought to be due to the fact that shiftworkers are awake and engaged during a time that our body clock and circadian rhythm are programmed to be asleep.
Although these symptoms and conditions are concerning, it’s clear that some industries must work around the clock. Especially industries such as public safety, healthcare, and transportation. Fortunately there are ways in which the negative effects of shiftwork can be minimized. Check back on Friday for info on how to lessen these effects.
At The Institute of Naturopathic Sleep Medicine, Dr. Darley provides care for people of all ages who have sleep problems. More at http://www.naturalsleepmedicine.net/
There are many ways that healthy sleep supports a healthy immune system. And remember, our immune system is constantly working to rid our bodies of foreign bacteria and abnormal cells. These abnormal cells can become cancerous, so it is important that our immune system weeds them out. To strengthen your immune system:
1. Be sure to get adequate rest most nights.
2. Sleep in accordance with the natural light-dark cycle. When the light bulb was invented and became widely available it significantly changed our way of life. Occasionally think to yourself “Would I be up right now if there was no electricity and light?” This question can help you stay in sync with natural light-dark cycles.
3. The techniques and skills we’ve discussed in this blog will help a cancer patient sleep better. Those include making the bedroom a good sleep environment, keeping a regular schedule, etc. (Past issues of the more comprehensive e-newsletters can be found on the website at http://naturalsleepmedicine.net/news_letters_page.html).
In honor of October being Breast Cancer Awareness Month, let’s look at the connection between sleep and cancer. This is a complex issue, as getting poor sleep increases the risk of cancer, and sleep in cancer patients is disturbed. Let’s look at each situation more closely.
Poor Sleep Increases the Risk of Cancer
In the last ten years research has been done looking at the life-long sleep histories of breast cancer patients. It’s been found that being awake at night (usually for shift work) increases the risk of developing cancer. This is thought to be because the light suppresses melatonin, which is highest during the dark night. In turn, when melatonin is low estrogen levels are increased, thus increasing risk of breast cancer. Colo-rectal cancer is also increased in women who have done shift work for 15 years or more. In addition to melatonin, cortisol patterns are irregular when a person is not sleeping well. Cortisol is important for our immune system.
It’s not only shift workers who suffer increased risk of cancer. Among physically active women, those who sleep less than 7 hours per night have a 47% increased risk of cancer compared to those who sleep more.
Sleep in Cancer Patients is Disrupted
Cancer patients experience sleep problems at a high rate. About 30-50% have insomnia, which worsens with repeat courses of chemotherapy. They also experience irregular sleep-wake patterns.