May 17 (UPI) -- Using a CPAP machine could reduce the risk for heart attack and stroke, even among those with non-sleepy obstructive sleep apnea, according to a study presented Monday during the American Thoracic Society's International Conference.
Continuous positive airway pressure devices, a common treatment for people with obstructive sleep apnea, or OSA, can help reverse the rise in heart rate many people with the condition who also have heart disease can experience during episodes, the data showed.
When coupled with heart disease, this increase in heart rate, or pulse, can raise a person's risk for heart attacks and strokes, the researchers said.
"Our study suggests that there is, in fact, a subgroup of non-sleepy patients with OSA for whom CPAP could provide a reduction in risk," study co-author Ali Azarbarzin said in a press release.
This includes "those with a higher pulse rate response to their respiratory events," said Azarbarzin, a researcher in the Division of Sleep and Circadian Disorders at Brigham and Women's Hospital in Boston.
Obstructive sleep apnea is a condition in which breathing stops involuntarily for brief periods of time during sleep in events called apneas or apneic episodes, according to the Sleep Foundation.
The most commonly used treatment, CPAP, therapy, uses a device to help people person breathe more easily during sleep by increasing air pressure in the throat so that it doesn't collapse when they breathe in, the foundation says.
Up to 5% of adults in the United States has some form of OSA, the foundation estimates, but research suggests that the non-sleepy type is far more common.
Those with non-sleepy OSA experience interrupted breathing during sleep, but do not report feeling tired or fatigued upon waking up, Azarbarzin and his colleagues said.
Because they do not experience daytime sleepiness, many people with non-sleepy OSA fail to seek treatment. Earlier studies indicated that CPAP offers little benefit for them, the researchers said.
This is despite research suggesting that they have approximately the same number of apneas as those who report daytime sleepiness.
For this study, Azarbarzin and his colleagues re-analyzed data on 206 non-sleepy OSA patients with heart disease from an earlier trial of the use of CPAP.
They assessed participants' heart rates using pulse oximetry and then matched their pulse rates with whether they had a heart attack or stroke while experiencing an apnea.
Some patients have a major surge in their heart rate at the end of apneas, while others have small increases, according to the researchers.
Those who experience surges are at increased risk for heart attacks or strokes compared to those who have small rises.
However, CPAP provided protection from heart attack and stroke in non-sleepy OSA patients whose pulse rates rose significantly during sleep apnea events, reducing risk by as much as 60%.
"The greater the pulse rate response, the greater the calculated treatment benefit of CPAP," Azarbarzin said.