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Fragmented sleep speeds cancer growth reports new study

After four weeks, the researchers found that the tumors in the mice with fragmented sleep patterns were twice as large as the tumors in the mice who had slept normally
After four weeks, the researchers found that the tumors in the mice with fragmented sleep patterns were twice as large as the tumors in the mice who had slept normally
Robin Wulffson, M.D.

Most are aware that getting a good night’s sleep is important for one’s health; however, a new study has found that fragmented sleep may promote the growth of tumors in cancer victims. The study was published online on January 21 in the journal Cancer Research by investigators at the University of Chicago and the University of Louisville.

The study authors note that fragmented sleep is a problem for many individuals. In addition, many individuals with fragmented sleep suffer from sleep apnea, which has been found to be associated with an increased risk of cancer. The investigators theorized that sleep fragmentation fuels tumor growth and progression via a process known as TLR4 signaling. For the study, the researchers used genetically engineered mice that had been injected with tumor cells. While the mice slept during the day, a quiet, motorized brush moved through half of the cages every two minutes; this caused the exposed mice to wake up and go back to sleep. The other mice were not disturbed as they slept.

After four weeks, the researchers found that the tumors in the mice with fragmented sleep patterns were twice as large as the tumors in the mice who had slept normally. The researchers explained that sleep deprivation can significantly affect the immune system. Cancer cells multiply because the immune system does not recognize them as being harmful to the body. Thus, fragmented sleep results in the cancer becoming more aggressive.

Last June, I interviewed a sleep expert, UCLA neuroscientist Christopher S. Colwell, PhD. He notes that about 50% of individuals over the age of 65 take sleeping aids on a regular basis. He believes that sleep aids have benefits for short-term use but not for long-term use; furthermore, data on adverse effects from long-term use are lacking. Dr. Colwell noted that when one takes a sleeping aid, normal sleep does not follow. Periods of REM sleep, when dreaming takes place, do not occur. Research has shown the REM sleep is necessary to maintain cognitive function. Although a stressful day, which is common for many Americans, is disruptive to sleep, Dr. Colwell pointed out other factors. In a primitive society, darkness signals the brain that it is time to rest. In the high-tech society we live in today, light exposure persists throughout the evening. Blue-green light disrupts sleep. This type of light is emitted by video games and, to a lesser extent, television sets. Limiting or avoiding exposure in the evening can help one sleep. Dr. Colwell recommends reading a book instead of playing a video game or watching TV before retiring. Inexpensive radios that emit white noise are available. This background noise is a proven sleep aid. If you live in a noisy neighborhood, consider adding sound-reducing material in your bedroom. He also noted that melatonin, which is available over-the-counter, can help one obtain a restful night’s sleep.

Take home message:
If you or a loved one suffers from cancer and has trouble sleeping, consultation with a sleep specialist can help. In addition, as Dr. Colwell noted, sleep medications—aside from melatonin—may not be beneficial for the long-term.