Sleep Disorders as a Risk Factor for Cardiovascular Disease

New research from Yale School of Medicine (YSM) highlights a powerful—and modifiable—tool for cardiovascular disease prevention.

In a recently published Journal of the American Heart Association study of nearly 1 million post-9/11 U.S. veterans, researchers found that adults with both insomnia and obstructive sleep apnea face substantially higher risks of hypertension and cardiovascular disease than those with either condition alone. The combination, known as comorbid insomnia and sleep apnea (COMISA), emerged as a distinct and harmful risk state.

“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 obstructive sleep apnea are typically diagnosed and treated separately. Insomnia involves difficulty falling or staying asleep, while sleep apnea is marked by repeated pauses in breathing during sleep. But in practice, the two frequently overlap—and interact in ways that worsen health outcomes.

“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.”

That interaction matters because sleep plays a foundational role in how the body regulates cardiovascular function overnight.

“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 repeated awakenings, shortened duration, or cessations of breathing—the heart and blood vessels lose the opportunity to recover, adapt, and reset, Zinchuk adds.

One of the goals of the study was to understand whether sleep disorders shape future cardiovascular risk, when prevention can still change long-term outcomes. “We wanted to know whether COMISA mattered early in the cardiovascular risk trajectory,” Gaffey says, “rather than decades later when disease is already established.”

Trouble sleeping, Gaffey emphasizes, is not merely inconvenient or something to push through. “Over time, it places a measurable strain on your cardiovascular system,” she says.

Zinchuk adds that prevention—not late-stage management—must guide future care in the sleep space.

Sleep should be assessed as routinely as other cardiovascular risk factors, according to the researchers, and insomnia and sleep apnea should be considered together. Sleep is a common, measurable, and treatable risk factor, and paying attention to it sooner could change the trajectory of cardiovascular disease.

The Department of Internal Medicine at Yale School of Medicine is among the nation's premier departments, bringing together an elite cadre of clinicians, investigators, educators, and staff in one of the world's top medical schools. To learn more, visit Internal Medicine.