Obstructive sleep apnea (OSA) is one of the most common sleep disorders. OSA occurs when there is reduced airflow when breathing during sleep. This happens because the soft tissues in the upper throat collapse, causing a blockage. OSA is associated with numerous cardiovascular disorders, such as: 

  • High blood pressure
  • Coronary heart disease
  • Cardiac arrhythmias
  • Sudden cardiac death
  • Heart failure
  • Pulmonary hypertension
  • Blood clots

It’s possible to reduce the risk of cardiovascular diseases associated with OSA if the condition is treated right away.

How does OSA affect the heart?

Uncontrolled OSA disrupts the body’s normal physiological processes. When apnea occurs, there is a decrease in airflow, causing oxygen to drop and carbon dioxide to rise. When OSA occurs, it causes brief awakenings during sleep. These disruptions happen so quickly; you won’t be remembered at all. When OSA occurs, the airway opens back up, and breathing becomes normal again. The fluctuations in breathing affect the oxygen level in the body, which can potentially lead to heart problems.

The body has two nervous systems: the sympathetic and parasympathetic nervous system. The sympathetic nervous system prepares the body for stress, the fight or flight response. The parasympathetic nervous system helps calm the body down and prevents major organs from working too hard. There is supposed to be a balance between the two systems. 

OSA is connected to an increase in the sympathetic nervous system during sleep. This leads to an increase in heart rate and blood pressure, among other physiological processes that cause an imbalance between the two nervous systems.

Health Problems Associated with OSA

High Blood Pressure (Hypertension – HTN)

Patients who suffer from OSA tend to suffer from HTN too. There is an increased risk of developing HTN in patients with OSA. Some studies show that severe OSA increases the risk of HTN despite being on medications. OSA affects the sympathetic nervous system, causing many stress hormones to be released into the bloodstream. The cocktail of stress hormones elevates blood pressure, causing undue stress to the organs. Sustained high blood pressure eventually leads to severe arterial and heart conditions.

Usually, blood pressure should decrease when sleeping. However, in patients with OSA, this does not happen. Interestingly, even patients who are taking blood pressure medications could suffer from uncontrolled OSA and cardiovascular disease. 

When OSA is treated, it can improve HTN. In fact, the more severe the OSA, the better the blood pressure. Alternatives therapies to OSA treatments, such as mandibular advancement device therapy and upper airway surgery, have also been shown to decrease elevated blood pressure.

Coronary Heart Disease (CAD)

OSA treatment decreases the risk of CAD. CAD is blockage of the arteries in the heart. If there is a blockage, this can lead to an acute myocardial infarction or “heart attack.” OSA can even worsen pre-existing heart disease. The incidence of major cardiac events (cardiac death, re-infarction, or blockage with heart damage) was higher in patients with OSA. Severe and untreated OSA is linked with a higher incidence of fatal and nonfatal cardiovascular events than patients, not on treatment. 

Atrial Fibrillation

There is a strong link between atrial fibrillation and OSA.  Atrial fibrillation is a condition that causes a “quivering” or irregular heartbeat. When the heart moves blood into the ventricles, the upper chamber of the heart quivers instead of beating normally. This can lead to a stroke by causing a blood clot to form in the heart chamber and travel to the brain. OSA could possibly cause repeat episodes of atrial fibrillation, even after treatment with either cardio version or ablation.

Other Arrhythmias

OSA is associated with other cardiac arrhythmias:

  • Tachycardia
  • Premature ventricular contractions (PVCs)
  • Atrioventricular (AV) block
  • Sinus pause
  • Asystole

One study showed treatment with CPAP reduced PVCs in patients with heart failure.

Sudden Cardiac Death (SCD)

OSA is also associated with fatal cardiac arrhythmias. The risk of sudden death increases among patients who stopped treatment. OSA appears to have a nocturnal (midnight to 6 AM) tendency to SCD. There is a threefold increase risk of SCD compared to people who do not have OSA.

Heart Failure

OSA is found in patients with heart failure. Heart failure occurs when the heart is not pumping strong enough to keep blood going to the rest of the body. Additionally, another kind of sleep apnea is also seen in patients with heart failure – central sleep apnea. This will be discussed further in another post. 

Pulmonary Hypertension

OSA is associated with pulmonary hypertension. Pulmonary HTN occurs when blood pressure is elevated in a large blood vessel connecting the heart to the lungs. CPAP therapy helps reduce stress in large blood vessels. The treatment could also control pulmonary HTN and keep the condition from worsening.


OSA may be a risk factor for venous thromboembolism (VTE) or blood clots. 

Putting it Together 

In conclusion, OSA is related to a variety of cardiovascular disorders. Treatment has been shown to help improve and decrease the risk of developing various heart problems.

I hope you found this helpful. Feel free to comment or leave a question. Hope you have a good night’s sleep!