A study published in the scholarly journal Cancer Research suggests that fragmented sleep, caused by sleep apnea, promotes cancer progression. How sleeping well is really not a waste of time!
In addition to being associated with an increased risk of obesity, cardiovascular disease and diabetes, studies indicate that lack of sleep also increases the risk of developing certain cancers. For example, people who sleep less than six hours a night have a 50% higher incidence of colorectal polyps (a major risk factor for colon cancer) than those who sleep more than seven hours.
Older men who have trouble sleeping also have a significantly increased risk of prostate cancer, especially for the more aggressive forms of the disease. In the same vein, postmenopausal women who suffer from insomnia are more at risk of being affected by thyroid cancer, but this lack of sleep does not seem to increase their risk of breast cancer.
Sleep apnea increases the risk of cancer and heart disease
You need to get enough sleep to prevent cancer, but the quality of that sleep is just as important. For example, people with sleep apnea see their risk of colorectal cancer greatly increased, even if they spend more than nine hours in bed.
These episodes of apnea are caused by an involuntary relaxation of the tongue and throat muscles, which obstructs the flow of air to the lungs and causes breathing pauses that can last several seconds. The ensuing lack of oxygen leads by reflex to momentary awakening (most of the time unconscious) and an increase in heart rate and blood pressure, which explains the increased risk of cardiovascular disease in those affected.
In parallel, the lack of oxygen associated with these frequent stops of breathing also activates certain hypoxia-sensitive proteins, in particular the hypoxia-inducible factor (HIF), which leads to an increase in proangiogenic and procancer factors such as VEGF which promotes tumor progression.
Sleep apnea promotes chronic inflammation
By examining the evolution of cancer cell tumors implanted in models, a research team from the University of Chicago observed that frequent sleep disruption was associated with faster growth of tumors, both in terms of their size than their ability to invade the tissues.
Microscopic examination of these tumors indicates that sleep fragmentation is associated with massive recruitment of inflammatory cells (macrophages) near cancer cells, these cells being known to secrete several inflammatory molecules that stimulate tumor cell growth.
Poor quality sleep is therefore not a simple “inconvenience” that disrupts our days due to greater fatigue. It is actually a major imbalance in the balance of the body, which creates a climate of inflammation
chronic capable of sustaining cancer progression.
How to Reduce Sleep Apnea
Overweight and obesity are the main causes of sleep apnea and people with a body mass index over 25 must therefore pay particular attention to certain signs that indicate poor quality sleep (very loud snoring , severe fatigue, headaches, irritability).
Losing a few extra pounds, exercising, preparing for sleep by avoiding activities that are too stimulating, and reducing your consumption of alcohol and rich foods at dinner are therefore changes that can help you get quality sleep.
For more serious cases, medical intervention using nocturnal ventilation devices may be necessary to restore quality sleep, increase quality of life and thus reduce the risk of premature death.
Hakim F et al. Fragmented sleep accelerates tumor growth and progression through recruitment of tumor-associated macrophages and TLR4 signaling. Cancer Res. 74:1329-37.