In June, in Baltimore, the sleep field held its fortieth annual SLEEP meeting, run jointly by the American Academy of Sleep Medicine and the Sleep Research Society. The argument running through it, and through the write-ups that followed, was a sentence that sounds like a wellness slogan and is not: chronic insomnia is a cardiovascular risk factor, not a nuisance. The claim is that insomnia belongs in the same risk conversation as high blood pressure, heart failure, coronary artery disease, and stroke, that treating bad sleep is in part treating your heart, and that the treatment is not a drug.
I want to believe this, so let me be careful with it, because "treat your sleep and save your heart" is exactly the shape of sentence I spent two years of my life writing for a supplement company. The difference is that this time the numbers are real, and the awkward part is not the science. The awkward part is that the treatment the field recommends is rationed almost to the point of fiction.
A real but modest risk, and only for the true short sleepers
Start with the risk, and start with the honest version. The relative risks attached to insomnia symptoms are modest. He and colleagues' 2017 meta-analysis in the European Journal of Preventive Cardiology, pooling fifteen prospective studies, found that difficulty falling asleep was associated with about a 27 percent higher risk of heart and stroke events (pooled relative risk 1.27), difficulty staying asleep with 11 percent, and non-restorative sleep with 18 percent. In the China Kadoorie Biobank, Zheng and colleagues followed 487,200 adults for nearly a decade and found each insomnia symptom went with a 7 to 13 percent higher risk of total cardiovascular disease. These are relative numbers. On a base rate, a 20 percent bump is a small absolute change for any one person, and I am not going to let a hazard ratio masquerade as a heart attack you were definitely going to have.
What lifts this above noise is dose and consistency. In Mahmood and colleagues' analysis of the US Health and Retirement Study, published in the European Heart Journal, 12,761 adults over fifty were tracked for sixteen years, during which 1,730 developed heart failure. People with one insomnia symptom had a 22 percent higher risk; with three, 66 percent; with four, 80 percent (hazard ratios 1.22, 1.66, and 1.80). Laugsand and colleagues' Norwegian HUNT cohort, 54,279 people followed for over a decade, found the same staircase: more symptoms, more heart failure, with the clearest signal in people who reported all three. A dose-response curve is the kind of thing that makes an epidemiologist stop rolling her eyes.
Here is the precision that gets sanded off in the wellness version, and it matters. For high blood pressure specifically, the risk is not carried by everyone who says they sleep badly. It is carried by insomniacs whose short sleep shows up on a machine. In Fernandez-Mendoza and colleagues' Penn State cohort, published in Hypertension in 2012, chronic insomnia paired with objective sleep under six hours in the lab carried almost fourfold higher odds of new hypertension (odds ratio 3.8); insomnia with normal measured sleep duration did not reach significance. A 2024 meta-analysis by Dai and colleagues in Sleep Medicine Reviews found the same split: insomnia with objective short sleep was associated with nearly double the risk of incident hypertension, while short sleep without insomnia was not a risk factor at all (pooled relative risk 0.97). So the useful sentence is narrower than the headline. An insomniac whose short sleep shows up on a machine is the group whose heart risk actually rises. "I feel tired" is not, by itself, a blood pressure emergency.
The obvious objection is confounding. Sick, stressed, poor, or depressed people sleep badly and also have worse hearts, so maybe insomnia is just riding along. This is the right objection, and it has been tested with the one tool that gets around it. Mendelian randomization uses gene variants dealt out at conception, before your job or your grief could touch them, as a natural experiment. Larsson and Markus, in Circulation in 2019, found genetic liability to insomnia associated with higher odds of coronary artery disease, heart failure, and ischemic stroke, though not atrial fibrillation. A 2021 study by Yuan and colleagues in the European Journal of Epidemiology went further: the link to heart failure survived, and actually strengthened, after adjusting for a genetic predisposition to depression. This is not proof, because the method leans on its own assumptions, but it moves insomnia meaningfully toward cause and away from bystander.
The proven fix is behavioral, not a pill
So say the reframe holds, roughly, with all those caveats intact. The treatment is the good part of this story. It is not a supplement, not melatonin, not the magnesium I still take at night and cannot fully defend. Every major guideline names cognitive behavioral therapy for insomnia, CBT-I, as first-line, ahead of sleeping pills. In the AASM's 2021 guideline, led by Edinger and colleagues, out of six behavioral interventions reviewed, multicomponent CBT-I is the single strong recommendation; the sleep medications get relegated to second string, for people who cannot do the therapy or still have symptoms after it. CBT-I is sleep restriction, stimulus control, and some cognitive work, usually four to eight sessions. It is boring, it is unglamorous, and in trials it also lowers blood pressure, C-reactive protein, and cortisol, which is the reframe that makes CBT-I look like cardiovascular risk reduction and not just a sleep fix.
The fix exists, but almost no one can get it
Now the receipt. When Thomas and colleagues counted the clinicians trained to deliver this, in a 2016 survey in Behavioral Sleep Medicine, they found 659 behavioral sleep medicine providers in the entire United States, and only 206 of them board-certified. Four states had none at all. Nineteen percent of the country's providers sat in just New York and California. This is the proven, non-commercial, guideline-endorsed treatment for a condition that, by Thomas Roth's 2007 review of insomnia epidemiology in the Journal of Clinical Sleep Medicine, affects roughly one in three adults at the symptom level and six to ten percent as a diagnosable disorder, and it is delivered by a few hundred people clustered in big cities. You cannot buy CBT-I at the pharmacy, and mostly you cannot get it from a human either.
Which is where the app stores arrive, and where I get nervous again. Digital CBT-I is the honest answer to the shortage, and it works: Hwang and colleagues' 2025 review in npj Digital Medicine, pooling 29 trials and 9,475 people, found moderate to large effects on insomnia severity. Sleepio, the most-studied program, posted large effect sizes for insomnia symptoms in its flagship trials, standardized effects around 1.5, in Espie and colleagues' 2019 randomized trial. But fully automated programs are consistently less effective than a real therapist, adherence is where they leak, and I would be doing my old job if I did not tell you that Colin Espie, who led those Sleepio trials, is also a cofounder, chief medical officer, and shareholder of Big Health, the company that sells it. That does not make the trials wrong. It makes them trials you read with your hand on your wallet.
The heart benefit is proven; a prevented heart attack is not
Where does the evidence actually stop. It stops here: CBT-I reliably improves the intermediate markers, the blood pressure and the inflammation and the cortisol. No randomized trial has yet shown that treating your insomnia prevents a heart attack, a stroke, or a heart-failure admission. That trial has not been run. So the responsible version of the Baltimore sentence is this. Chronic insomnia looks like a genuine, partly causal contributor to heart disease, the risk concentrates in people who really are sleeping short, and the best treatment we have is a behavioral therapy that is safe, drug-free, and almost impossible to actually obtain.
The problem was never that we lacked a treatment. It is that we built a health system that can sell you a mattress, a ring, and a bottle of magnesium overnight, and makes you wait months for the one therapy proven to fix the sleep, and to move the blood pressure and inflammation that ride along with it.
