Snoring is the main symptom of sleep apnea, a disorder in which your breathing becomes shallow or even stops for a while during the night. People with severe sleep apnea are almost five times as likely to die of cancer than those who breathe easy while they sleep, according to a new study presented last week at the American Thoracic Society conference. The study, which tracked 1,500 people for 22 years, found that mild or moderate snoring also increases your risk of cancer death.
Sleep apnea reduces the oxygen level in your blood; to avoid suffocating, tumors grow new blood vessels, says study author F. Javier Nieto, M.P.H., M.D., Ph.D., of the University of Wisconsin-Madison School of Medicine and Public Health. These extra veins and arteries help existing tumors grow faster and give cancer cells more opportunities to spread through your bloodstream to new parts of your body.
It’s not yet clear whether sleep apnea increases your risk of getting cancer or just worsens existing cases, and more research is needed to confirm the results. But snoring is cause for concern either way—leading to accidents, depression, high blood pressure, and heart disease. If you snore and are sleepy during the day, check with your doctor, especially if you’re carrying a few extra pounds (they increase your sleep apnea risk). Other signs of sleep apnea include grumpiness, forgetfulness, and headaches that are hard to shake.
In the meantime, sleeping on your side instead of your back can help some mild cases of sleep apnea.