‘Silent Nightmares’ Triple Heart Risk

Woman lying awake in bed beside an alarm clock — Photo: Ground Picture / Shutterstock

People who can’t fall asleep and people who stop breathing during sleep face a much bigger heart risk when both problems hit at once.

Quick Take

A study of nearly one million veterans found combined insomnia and sleep apnea, called COMISA, tied to triple the risk of cardiovascular disease.
The same combination was linked to more than double the risk of high blood pressure.
Having both conditions carried far more risk than having either one alone.
The findings come from Veterans Health Administration records tracked over up to 20 years.

What The Veterans Data Actually Showed

Researchers followed close to one million post-9/11 veterans for up to two decades, splitting them into four groups: people with neither sleep problem, insomnia alone, sleep apnea alone, and people with both. After adjusting for age, lifestyle, and other health conditions, the combined group, known as COMISA, stood out sharply. That group faced a greater than twofold jump in new high blood pressure cases and roughly triple the rate of new cardiovascular disease compared to people with no sleep disorder at all. Yale researchers involved in the work describe COMISA as its own dangerous category, not just a mash-up of two milder problems. Their summary states the combination “emerged as a distinct and harmful risk state,” separate from insomnia or sleep apnea on their own. That distinction matters because it tells doctors the two conditions don’t just add up, they seem to multiply danger when they show up together in the same patient.

This pattern isn’t a one-off. A related study of over one million post-9/11 veterans found insomnia alone was tied to a 32% higher risk of developing atrial fibrillation, an irregular heartbeat condition, even after accounting for sleep apnea and other factors. That’s a different heart condition than the broader cardiovascular disease outcome in the COMISA study, so the two findings shouldn’t be blended together as if they prove the exact same thing. But they point in the same direction: bad sleep and heart trouble keep showing up as neighbors.

Why This Matters Beyond The Veteran Community

The study population is entirely made up of veterans receiving care through the Veterans Health Administration, a group that skews younger and middle-aged compared to the general public. That doesn’t make the finding meaningless for everyone else, but it does mean doctors should be cautious before assuming the same tripled risk applies identically to an 70-year-old civilian retiree or someone without military health benefits.

Diagnoses in the study came from clinical records rather than sleep lab testing on every single participant. People who see doctors more often also get diagnosed more often, and they get more chances for high blood pressure or heart disease to show up on a chart. Researchers adjusted for many factors, but no observational study can promise every bit of that bias got erased. The headline number is real and alarming, but it describes an association, not lab-proven cause and effect.

What Still Needs To Be Answered

No study yet has proven that treating COMISA with a CPAP machine, insomnia therapy, or both together actually lowers a patient’s chance of a heart attack or stroke. Broader research on sleep apnea treatment backs that caution up: a review of randomized trials found CPAP therapy alone wasn’t consistently linked to fewer major cardiovascular events, even though it clearly improved sleepiness and quality of life. That gap between observed risk and proven treatment benefit is exactly where more research needs to go next.

Worth adding: insomnia with sleep apnea (COMISA) responds to CBT-I too. In an RCT of 145 adults, CBT-I before CPAP improved insomnia and raised CPAP use by about an hour a night (Sweetman et al., Sleep 2019).

— Clyr Health (@ClyrHealth) November 1, 2026

None of this uncertainty erases the core finding. A massive, long-running study found a clear and strong link between the two sleep problems together and serious heart trouble down the road. For anyone who tosses and turns at night and also gets told they snore like a freight train, that combination is worth mentioning to a doctor, not brushing off as two separate annoyances.