In a study published in the Journal of the American Heart Association, scientists analyzed data from nearly 1 million post-9/11 U.S. veterans. They discovered that adults who have both insomnia and obstructive sleep apnea face a significantly higher risk of high blood pressure and cardiovascular disease compared with those who have only one of the conditions. This combination, called comorbid insomnia and sleep apnea (COMISA), stood out as a particularly harmful risk category.

“We spend an enormous amount of time managing cardiovascular disease downstream, but far less time addressing more upstream modifiable risk factors,” says Allison Gaffey, PhD, assistant professor of medicine (cardiovascular medicine) at YSM and first author of the paper. “Sleep disturbances, which are common in the veteran population, are often treated as secondary problems.”

Insomnia and Sleep Apnea Often Overlap

Doctors usually diagnose and treat insomnia and obstructive sleep apnea as separate disorders. Insomnia makes it hard to fall asleep or stay asleep. Sleep apnea involves repeated pauses in breathing during the night. However, many people experience both conditions at the same time, and when they occur together, the health effects can intensify.

“These conditions don’t just coexist politely,” Gaffey says. “Treating one while ignoring the other is a bit like bailing water out of a boat without fixing the leak.”

Why Disrupted Sleep Strains the Heart

The connection is important because sleep is essential for regulating the cardiovascular system. During healthy sleep, the heart and blood vessels have time to rest, repair, and reset.

“Sleep touches every single part of our existence,” says Andrey Zinchuk, MD, MHS, associate professor of medicine (pulmonary, critical care, and sleep medicine) at YSM and senior author of the paper. “Oftentimes, it is neglected even though it has such an important impact on our lives.”

When sleep is repeatedly disrupted by frequent awakenings, shorter sleep duration, or pauses in breathing, the cardiovascular system loses critical recovery time. Zinchuk explains that without this nightly reset, the heart and blood vessels cannot properly adapt and restore balance.

Prevention and Early Cardiovascular Risk

A key aim of the study was to determine whether sleep disorders influence cardiovascular risk early enough for prevention to make a difference. “We wanted to know whether COMISA mattered early in the cardiovascular risk trajectory,” Gaffey says, “rather than decades later when disease is already established.”

According to Gaffey, ongoing sleep problems should not be dismissed as minor frustrations. “Over time, it places a measurable strain on your cardiovascular system,” she says.

Zinchuk emphasizes that future care must prioritize prevention rather than waiting to treat advanced disease.

The researchers recommend evaluating sleep as routinely as other major cardiovascular risk factors. Insomnia and sleep apnea should be assessed together instead of in isolation. Because sleep problems are common, measurable, and treatable, identifying and addressing them early could significantly alter the course of cardiovascular disease.