Could The Way You Breathe At Night Reveal Your Heart Disease Risk?
Snoring, restless nights, and waking up feeling like you barely slept can all be signs of sleep apnea. But there's more happening behind the scenes than simply stopping and starting breathing.
During sleep, your brain and lungs work together to keep oxygen and carbon dioxide levels balanced. When that system becomes overly sensitive, breathing can fall into a repetitive cycle of disruption.
Now, new research is exploring whether this particular pattern could offer another clue about someone's long-term heart health.
About the study
Sleep apnea is usually measured by counting how many times a person's breathing stops or slows down each hour. But this doesn't tell the whole story of what's happening while they sleep. It doesn't account for how steadily or erratically the body controls breathing throughout the night.
That's what researchers wanted to investigate. They focused on something called loop gain, which describes how strongly the brain reacts when oxygen and carbon dioxide levels change.
If this system is too sensitive, it can overcorrect, causing breathing to repeatedly speed up, slow down, and become disrupted.
To explore whether this pattern could affect heart health, researchers analyzed data from two large studies, the Sleep Heart Health Study and the Multi-Ethnic Study of Atherosclerosis.
They used two measurements to identify people whose breathing repeatedly sped up and slowed down in a more regular, predictable cycle.
This wasn't necessarily a measure of how many times they stopped breathing, but rather how repetitive and unstable their breathing patterns were. Researchers then examined how this related to cardiovascular disease and deaths from cardiovascular causes.
This breathing pattern was linked to higher heart disease risk
Across both studies, people whose breathing followed the most repetitive cycles of instability were more likely to develop cardiovascular disease.
In the Multi-Ethnic Study of Atherosclerosis, this group had a 69% higher likelihood of developing cardiovascular disease. In the Sleep Heart Health Study, the likelihood was 24% higher. The association also appeared stronger in men than in women.
Researchers also looked at deaths related to cardiovascular disease. They found that people with greater breathing instability were more likely to die from cardiovascular causes in both studies, with a stronger relationship again seen in men.
However, when they compared people with the highest levels of breathing instability against everyone else, the link to cardiovascular deaths wasn't consistent across the two studies.
Age also complicated the picture. When researchers adjusted their calculations to account for age more precisely, the connections between breathing instability and heart health became considerably weaker.
This suggests that age may explain some of the increased risk they initially observed.
Why your sleep apnea score may not tell the whole story
These findings suggest that the frequency of breathing interruptions isn't the only factor worth investigating when assessing sleep apnea.
Two people could have similar scores on a standard sleep apnea test but different patterns of breathing instability, potentially carrying different cardiovascular risks.
For now, this doesn't mean that everyone with this particular breathing pattern will develop heart disease, or that standard sleep apnea assessments are inadequate. Rather, it highlights an additional factor researchers may want to investigate when studying how sleep apnea affects the heart.
The stronger associations observed in men are also worth exploring.
However, more research is needed to understand why these differences exist and whether they hold up across other populations.
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What to do if you suspect you have sleep apnea
You don't need to know your loop gain or respiratory self-similarity score to take your sleep health seriously. Recognizing the signs of sleep apnea is a much more useful place to start.
- Watch for nighttime symptoms: Regular snoring, gasping, choking sounds, or pauses in breathing during sleep can be signs of sleep apnea.
- Pay attention to daytime fatigue: Excessive sleepiness, even after spending a full night in bed, is another reason to speak with a health professional.
- Follow your prescribed treatment: If you've been diagnosed, stay consistent with your recommended approach, whether that's a CPAP machine or an alternative. Keep up with follow-up appointments so your care team can monitor your progress.
If you recognize these symptoms, bring them up with a health professional. A sleep evaluation can help determine whether you have sleep apnea and what treatment may be appropriate.
The takeaway
Sleep apnea may have more cardiovascular implications than a standard breathing-event count can reveal.
The rhythm of those disruptions could offer another piece of the heart-health puzzle, particularly for men, although more research is needed to understand the connection.
