If you're dutifully strapping on a CPAP mask each night for obstructive sleep apnea (OSA), it’s probably helping your snoring and daytime fog. But is it helping your heart?
Maybe not. Recent research pooling results from three major clinical trials has found that CPAP (continuous positive airway pressure) reduces the risk of serious heart problems associated with OSA (including heart attack, stroke, and early death) in some patients but not in others — and in certain cases, it may be even harmful.
Mount Sinai sleep expert Vaishnavi Kundel, MD, says the reason is clear: OSA isn't just one disease. While all OSA involves a collapsed airway at night, the root causes can differ. When excess weight is the driver, a CPAP can keep the airway open but doesn’t address what’s happening in the rest of the body.
Why CPAP Alone May Fall Short
When you repeatedly stop breathing at night, your blood oxygen drops and your body releases stress hormones. Over time, this can strain your heart, raise your blood pressure, and promote inflammation.
CPAP eliminates these interruptions, which is why it works well for symptoms like daytime sleepiness, morning headaches, and cardiovascular stress caused by airway collapse.
But obesity harms the cardiovascular system in ways that aren’t fixed by CPAP.
Too much fat — especially visceral fat around the organs — acts as an endocrine organ that pumps out inflammatory molecules called adipokines. These adipokines contribute to atherosclerosis, insulin resistance, and blood vessel dysfunction. They circulate continuously, day and night.
"Obesity is estimated to be responsible for 58% of moderate to severe OSA and 41% of mild OSA," Kundel said at a recent sleep medicine conference. For these patients — roughly half of everyone with the condition — CPAP corrects the airway problem but doesn't treat the systemic inflammation.
That may partly explain why those three big trials, conducted over the last decade, found CPAP did not help reduce cardiovascular risk overall for OSA patients. But now, researchers are digging deeper into that data, revealing a more nuanced — and more hopeful — story.
What New Research Shows
In a 2024 study, Kundel and colleagues found that the broad result from those trials was hiding important differences between patients: Some benefited from CPAP, others didn’t.
The key wasn't just how often breathing stopped, but what happened during each event: how long it lasted, how low oxygen levels dropped, and how much their heart rate spiked.
Those with more severe physiological responses benefited from CPAP, while those with milder responses didn't. One troubling finding: People with a history of stroke, poor exercise habits, and low baseline oxygen levels during sleep actually had worse outcomes with CPAP — including a sixfold higher risk of another cardiovascular event.
Why? It could be that the pressure from CPAP strains the cardiovascular system, or that CPAP disrupts sleep (a risk factor for heart problems), researchers speculated in a 2025 study.
Why This Matters More for Women
Because many women don’t have classic OSA symptoms — like loud snoring — they often go undiagnosed for years. Instead, women tend to report insomnia, fatigue, morning headaches, anxiety, depression, and brain fog — symptoms that may be brushed off as signs of stress, mood disorders, hormonal fluctuations, or poor sleep.
That gives sleep apnea, and the weight-related factors driving it, extra time to quietly strain the heart and overall health. By the time a woman finally gets a CPAP, she may have built up risks that the machine alone can't undo.
Kundel's research suggests sleep apnea in women may be more intertwined with obesity and systemic inflammation.
That doesn’t mean women should abandon CPAP, but it does mean they should consider whether it might work better as part of a larger strategy.
A More Personalized Approach
This is where new weight loss medications known as GLP-1 agonists — semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) — are reshaping sleep medicine.
These drugs can achieve a 20% weight reduction — which is associated with a 57% reduction in sleep apnea severity, Kundel said. In a large clinical trial, 40%-50% of patients with moderate to severe OSA taking tirzepatide achieved mild or no sleep apnea.
But even after weight loss, many patients still have breathing issues, Kundel said: "For these patients, combination therapy with CPAP and GLP-1s is really a practical approach.” The drugs have also been shown to reduce cardiovascular risk by 20%.
The bottom line for women living with OSA: Talk to your doctor about what’s driving your OSA and whether CPAP alone is the right protection for your heart. If body weight may be the culprit, ask whether you might be a candidate for GLP-1 drugs or other weight loss interventions.
