Obstructive sleep apnea is a condition that causes chronic blockage of the airway. People with apnea experience interrupted breathing during sleep, and frequently also suffer from hypertension and heart disease. Those diagnosed with this disorder are frequently treated with a so-called C-PAP machine to help regulate their breathing during sleep. Researchers in Spain looked into whether the device also helped reduce patients' hypertension and cardiovascular issues.

Anyone whose husband, wife or partner who snores loudly is probably wishing for a separate bedroom. It's the telltale sign of obstructive sleep apnea, a chronic disorder in which the person experiences shallow breathing or frequent pauses in breathing while asleep.

In apnea, throat muscles and other tissue in the back of the throat periodically block the airway.

The brain reacts by lifting the throat muscles away from the windpipe and the individual wakes up often struggling for air. By then, researchers say, the level of blood oxygen has dropped and the quality of sleep has been affected by stress hormones.

Obstructive sleep apnea affects less than 10 percent of people across many countries. More men than women have it, and it is more common among the elderly.

"At night, sometimes I wake up without air and sometimes my husband [says] I snore a lot," said Montse Oliver who suffers from the condition.

If left untreated, sleep apnea increases the risk of high blood pressure, obesity, cardiovascular disease such as heart attack and stroke. New research also raises a possible link to cancer.

The standard treatment for this disorder is C-PAP, or continuous positive airway pressure. The machine blows a controlled stream of air down the throat, correcting the blockage. Patients should feel rested after a good night's sleep.

But researchers in Spain wanted to know how effective C-PAP is in treating hypertension and cardiovascular symptoms in sleep apnea patients, in particular those who did not experience sleepiness during the day.

Dr. Ferran Barbè from the Research Institute in Llieda and colleagues studied more than 700 patients with the sleep disorder and followed up over four years. Some of the patients used the C-PAP machine. Others did not.

"We found a slight decrease in the incidence of hypertension and new cardiovascular events in the C-PAP group," said Barbè. "However, the results did not reach a statistically significant difference.

A second study, also in Spain, looked at whether C-PAP reduced blood pressure in apnea patients recently diagnosed with hypertension.

That study did show a reduced risk of hypertension by almost 30 percent compared to the control group.

While both studies document the benefits of C-PAP, the researchers say larger studies with longer follow-up are needed.

The studies were published in the Journal of the American Medical Association.

C-PAP: 持續(xù)氣道正壓通氣

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睡眠障礙 sleep disorder

（來(lái)源：VOA 編輯：旭燕）