• Dennis Thompson
• Posted August 6, 2025

CPAP Might Increase Heart Risk For Some Sleep Apnea Sufferers

Thinking about using a CPAP machine to quell sleep apnea?

It’s not necessarily a good idea for everyone, a new evidence review argues.

This common treatment for sleep apnea might increase some folks’ risk of heart attack, stroke and heart-related death, according to results published today in the European Heart Journal.

CPAP machines can dramatically lower a person’s heart risk if severe sleep apnea causes dramatic drops in blood oxygen levels or large surges in heart rate, researchers found by analyzing data from more than 3,500 participants in three major clinical trials.

But CPAP might escalate heart health risk among people with milder sleep apnea, particularly if the condition doesn’t cause them to feel sleepy during the daytime, results show.

“Our findings suggest that CPAP may offer long-term cardiovascular benefit in people with high-risk obstructive sleep apnea, but may have unintended harmful effects in those without high-risk OSA,” lead researcher Ali Azarbarzin, a sleep medicine investigator at Brigham and Women’s Hospital in Boston, said in a news release.

Sleep apnea occurs when the muscles in the back of the throat relax, causing a person’s airway to collapse. 

These folks tend to snore, and if the airway collapses completely their breathing can start and stop throughout the night, causing them to repeatedly wake.

Continuous positive airway pressure (CPAP) machines blow air through a face mask as a person sleeps. The air pressure prevents the person’s airways from closing.

Sleep apnea has been previously linked to heart disease, researchers noted. It’s been reported to increase the risk of heart failure by 140%, stroke by 60% and heart disease by 30%.

But prior studies of CPAP treatment for sleep apnea have not shown a clear benefit to heart health from the devices, Azarbarzin said.

In an attempt to clarify CPAP’s heart benefits, Azarbarzin and colleagues pooled together data from three separate trials that tested CPAP for people with sleep apnea.

Results showed a clear benefit for people with high-risk sleep apnea that causes dramatic changes in blood oxygen and heart rate. Overall, these patients had a 17% lower risk of heart attack, stroke and heart-related death.

But in people without high-risk sleep apnea who don’t feel sleepy during the day, CPAP appeared to increase their risk of serious heart problems by 30%, researchers said.

“For people with high-risk OSA, CPAP likely helps by preventing low oxygen levels and calming the overactive sympathetic nervous system during sleep,” Azarbarzin said. Both are linked to heart disease.

“But in people without these high-risk markers, who are already at very low cardiovascular risk, CPAP seems to have downsides,” Azarbarzin added. “While we don’t really know why, one possibility is that the pressure used in CPAP may stretch the lungs in a way that puts stress on the cardiovascular system. Another is that CPAP could disturb sleep for some people, and sleep disruption itself is a risk factor for cardiovascular problems.”

The results indicate the need for personalized treatment of sleep apnea, Azarbarzin said.

“Instead of treating everyone the same, we should consider whether someone has high-risk features,” Azarbarzin said. “These are the people who seem most likely to benefit from CPAP.”

However, more research is needed to better understand the potential risks posed by CPAP, Azarbarzin said.

“CPAP-related harm was seen only in non-sleepy patients with existing heart disease, according to the design of trials analyzed in this study,” Azarbarzin said. “Whether this applies to other patients remains unknown and needs further research.”

More information

Yale Medicine has more on sleep apnea.

SOURCES: European Society of Cardiology, news release, Aug. 6, 2025; Mass General Brigham, Aug. 5, 2025