At a Glance
Sleep apnea can strain the cardiovascular system because repeated breathing interruptions lower oxygen levels and trigger stress responses in the body. Over time, untreated sleep apnea is linked to higher risks of high blood pressure, irregular heart rhythms, heart attack, stroke, and worsening heart failure.
If you have sleep apnea, it’s not just your sleep that’s at risk; your heart health may be affected, too. Repeated pauses in breathing can lower oxygen levels and place added strain on the cardiovascular system, which may increase the risk of conditions like high blood pressure, heart disease, and stroke.
In this article, we’ll explore the connection between sleep apnea and heart health, including why the two are linked and how treatment may help reduce risk.
Don’t Ignore the Warning Signs. Get Answers.
Sleep Doctor’s home sleep study helps you understand if sleep apnea could be impacting your health and what to do next.
How Does Sleep Apnea Impact the Heart?
Sleep apnea affects the heart by repeatedly interrupting breathing and causing drops in blood oxygen levels, which forces the body to react quickly to restore normal breathing. During each apnea event, oxygen levels fall, carbon dioxide levels rise, and the body releases stress hormones like adrenaline.
These surges cause the heart rate to spike and blood vessels to constrict, leading to sudden increases in blood pressure. At the same time, the chest muscles must work harder to breathe against a blocked airway, creating negative pressure inside the chest that further strains the heart. This combination of oxygen deprivation, hormone surges, and mechanical stress can occur dozens or even hundreds of times per night.
Over time, this cycle can lead to chronic high blood pressure, increased inflammation, and more strain on the heart, all of which raise the risk of long-term cardiovascular problems.
Untreated sleep apnea can also reduce sleep quality and lead to sleep deprivation, which can affect heart health in many ways. Research has found that people who sleep less than six hours each night are at higher risk of heart attacks. Sleep loss is also linked to several risk factors for heart disease:
- Cholesterol buildup in the arteries
- Inflammation
- High blood pressure
- High blood sugar
- Obesity
Can Sleep Apnea Cause Heart Problems?
The relationship between sleep apnea and heart disease may run in both directions. Symptoms of obstructive sleep apnea (OSA), which is caused by repeated collapse or blockage of the upper airway during sleep, may worsen after a heart attack. Severe heart failure can also cause a form of central sleep apnea (CSA), in which the brain doesn't consistently send signals to the muscles that control breathing, leading to irregular breathing patterns.
When people have obstructed breathing during sleep, their bodies react in several ways that can affect the heart:
Low Blood Oxygen Levels
Sleep apnea can cause repeated drops in blood oxygen levels during the night due to pauses in breathing. This pattern forces the heart to work harder to deliver oxygen to the body. Over time, low oxygen levels can damage blood vessels, increase inflammation, and disrupt normal heart function, all of which contribute to a higher risk of cardiovascular disease.
High Blood Pressure
Blood pressure typically drops during sleep, giving the heart a chance to rest. In people with OSA, this natural dip is often reduced or absent. Each time breathing stops, the body briefly wakes to reopen the airway, triggering a surge in stress hormones that raises blood pressure. Over time, these repeated spikes can lead to chronic high blood pressure (hypertension) that persists even during the day.
Pulmonary Hypertension
Sleep apnea can also increase pressure in the blood vessels that carry blood from the heart to the lungs, a condition known as pulmonary hypertension. Low oxygen levels cause these blood vessels to constrict, making it harder for blood to flow through the lungs. As a result, the right side of the heart must work harder to pump blood, which can eventually lead to right-sided heart enlargement or weakness if left untreated.
Heart Attack
Obstructive sleep apnea is associated with a higher risk of heart attacks (myocardial infarctions). Repeated drops in oxygen, increased blood pressure, and ongoing inflammation can contribute to plaque buildup and instability in the arteries, raising the likelihood of a blockage.
People with OSA may also be more prone to chest pain (angina) due to reduced blood flow to the heart. For those who have already had a heart attack, untreated sleep apnea can increase the risk of recurrence and poorer recovery outcomes.
Heart Disease
Untreated OSA can contribute to the development of heart disease and make existing conditions worse. Over time, the frequent drops in oxygen levels, sleep disruptions, and increased effort to breathe associated with OSA can damage blood vessels and increase the risk of coronary artery disease, in which plaque builds up in the arteries that supply the heart.
Heart Failure
Sleep apnea can both contribute to and worsen heart failure, a condition in which the heart cannot pump blood effectively. Repeated breathing interruptions increase strain on the heart by causing oxygen deprivation, pressure changes in the chest, and surges in stress hormones. These effects can weaken the heart over time and are linked to a higher risk of hospitalization and death in people with heart failure.
As mentioned above, severe heart failure can also lead central sleep apnea. Unlike OSA, which is caused by airway blockage, CSA occurs when the brain doesn’t consistently send signals to the muscles that control breathing, leading to irregular breathing patterns.
AFib
People with OSA are more likely to develop atrial fibrillation (AFib) and other irregular heart rhythms. Repeated oxygen drops and surges in stress hormones can disrupt the heart’s electrical system, increasing the likelihood of abnormal rhythms. In addition, the pressure changes that occur during apnea events can stretch the heart’s upper chambers, which may further contribute to AFib. Sleep apnea can also make AFib more difficult to treat and more likely to recur, especially if the underlying breathing disorder isn't addressed.
Stroke
Sleep apnea can impact other parts of the cardiovascular system in addition to the heart. People with OSA have a higher risk of stroke than people without OSA do. People with untreated or more severe OSA are more likely to have a stroke than people with mild or treated OSA. In addition, people who have recently had a stroke are at higher risk of developing CSA.
Atherosclerosis
OSA has also been linked to a condition of the arteries called atherosclerosis. This condition involves a build-up of plaque in the arteries and increases a person's risk of heart attack and stroke. Experts believe there are many factors that may lead to diseased arteries in people with OSA, including OSA's tendency to trigger the nervous system and cause inflammation.
Does Treating Sleep Apnea Reduce Risk of Heart Disease?
Treating sleep apnea can improve heart health. However, sleep apnea treatment may not improve or prevent all heart conditions. Talk to your doctor if you have both sleep apnea and a heart condition. People with both conditions may need both sleep apnea therapy and treatment for heart disease.
Continuous positive airway pressure (CPAP) is the main treatment for both OSA and CSA. Studies have found that CPAP treatment for sleep apnea positively affects several heart conditions.Some people with sleep apnea want or need alternatives to CPAP. The impact of CPAP therapy on heart health has been studied more than alternative treatments. However, some alternative therapies have been studied, including oral appliances and adaptive servo-ventilation (ASV).
Frequently Asked Questions
In some cases, early or mild heart changes caused by sleep apnea may improve with treatment, especially with consistent use of CPAP therapy. Treating sleep apnea can help lower blood pressure, reduce strain on the heart, and improve overall cardiovascular function. However, more advanced or long-term damage may not be fully reversible, which is why early diagnosis and treatment are important.
Yes, sleep apnea can contribute to an enlarged heart (cardiomegaly) over time. Repeated drops in oxygen and increased pressure in the chest can force the heart to work harder, particularly the right side that pumps blood to the lungs. This extra workload can cause the heart muscle to thicken or enlarge, which may eventually affect how well the heart functions.
Sleep apnea can cause changes in heart rate, including brief periods of slower heart rate (bradycardia) during apnea events at night. However, a persistently low heart rate during the day is less common and may be related to other factors or underlying conditions. If you notice symptoms like dizziness, fatigue, or fainting along with a low heart rate, it’s important to talk to a healthcare provider for evaluation.
Yes, sleep apnea can contribute to a fast heart rate (tachycardia), particularly during and after breathing interruptions at night. When oxygen levels drop, the body activates a stress response that releases adrenaline, causing the heart rate to rise quickly. If you notice a consistently fast or irregular heartbeat, it’s important to speak with a healthcare provider.
Medical Disclaimer: This content is for informational purposes and does not constitute medical advice. Please consult a health care provider prior to starting a new treatment or making changes to your treatment plan.
Written by
Elizabeth Rausch-Phung, MD, Contributing WriterDr. Rausch-Phung is a board-certified preventive medicine physician and a freelance medical writer specializing in health, wellness, and prevention with a passion for health communication.
Reviewed by
Gerard J. Meskill, MD, FAASM, Medical ReviewerDr. Gerard J. Meskill is a neurologist and sleep medicine physician specializing in the diagnosis and treatment of sleep disorders, including narcolepsy, obstructive sleep apnea, and insomnia. He is board-certified in both neurology and sleep medicine and has extensive experience helping patients manage complex sleep conditions and disorders of excessive daytime sleepiness.
