High blood pressure is one of the most important risk factors for heart attack and stroke. Elevated blood pressure can have many underlying causes, such as obesity, stress, or kidney disease. Sleep apnea is already known as a contributing factor – but for the first time, this study shows that the combination of sleep apnea and insomnia represents the strongest risk factor for uncontrolled hypertension.
Sleep apnea involves repeated pauses in breathing during the night, leading to oxygen deficiency and disturbed sleep. Insomnia refers to long-term sleep difficulties – such as trouble falling asleep, frequent awakenings during the night, or waking too early in the morning.
Four groups studied
The study included nearly 4,000 randomly selected middle-aged adults from the general population. Participants underwent extensive health examinations, including blood pressure measurements and an overnight home sleep study. They were divided into four groups: those without sleep problems (2,616 people), those with insomnia (404), those with sleep apnea (694), and those with both problems (118). Blood pressure readings above 140/90 mmHg were considered high.
The results showed that 4.5 percent of people with insomnia alone had high blood pressure, compared with 7.9 percent of those with sleep apnea alone and 10.2 percent of those with both conditions.
Identifying high-risk patients
Mio Kobayashi Frisk, physician at Sahlgrenska University Hospital and doctoral student at Sahlgrenska Academy, University of Gothenburg, is lead author of the study:
“We see that it is specifically the combination of sleep apnea and insomnia that is most clearly linked to high blood pressure. This is important knowledge for identifying patients who are at the greatest risk and need closer monitoring in healthcare,” says Mio Kobayashi Frisk.
Ding Zou, researcher at Sahlgrenska Academy, University of Gothenburg, is senior author of the study:
“Good sleep is now part of the international recommendations for protecting heart health. For patients with both sleep apnea and insomnia, treatment with a breathing mask may not always be enough – support with sleep habits or cognitive behavioral therapy can also be important to reduce the risk of high blood pressure,” says Ding Zou.
The study is part of SCAPIS, a large population study funded by the Swedish Heart-Lung Foundation. The results are published in the journa l Annals of the American Thoracic Society.
Annals of the American Thoracic Society
10.1513/AnnalsATS.202501-080OC
Observational study
People
Co-morbid Insomnia and Sleep Apnea Is Associated with Uncontrolled Hypertension in a Middle-aged Population
8-Sep-2025