Scientists say the combination of insomnia and sleep apnea could quietly increase the risk of heart disease.
New research from Yale School of Medicine (YSM) points to a powerful and adjustable factor that could help reduce the risk of cardiovascular disease.
In a study published in the Journal of the American Heart Association, researchers analyzed data from nearly 1 million post-9/11 U.S. veterans. The team found that adults who experience both insomnia and obstructive sleep apnea face a much greater risk of hypertension and cardiovascular disease than people with only one of these conditions. The overlapping condition, called comorbid insomnia and sleep apnea (COMISA), stood out as a particularly harmful risk profile.
“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.”
When Insomnia and Sleep Apnea Occur Together
Insomnia and obstructive sleep apnea are usually diagnosed and managed as separate disorders. Insomnia refers to persistent difficulty falling asleep or staying asleep. Sleep apnea involves repeated pauses in breathing that interrupt sleep throughout the night. However, many people experience both conditions at the same time, and their combined effects can 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.”
Why Sleep Disruption Strains the Heart
The connection matters because sleep plays a crucial role in regulating the cardiovascular system 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.”
Zinchuk explains that when sleep is repeatedly interrupted—whether from frequent awakenings, shortened sleep time, or pauses in breathing—the heart and blood vessels miss an important opportunity to recover and rebalance.
