Sleep Apnea Doubles Risk for Sudden Cardiac Death

by | Last updated Oct 25, 2022

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If you have obstructive sleep apnea you have an increased risk for numerous cardiovascular conditions from congestive heart failure to coronary artery disease to hypertension. 

You’ll find many articles on our website including how sleep apnea increases the risk of heart disease, how sleep apnea contributes to high blood pressure, and how nighttime arousals lead to heart disease in women.

These articles discuss at length why it’s important that you address any sleep issues you may have, including getting tested for and potentially treated for sleep apnea if you have heart health concerns. 

Recently published research by Penn State University further underscores and highlights the importance of seeking diagnosis and if needed, treatment. 

If you’ve been diagnosed with sleep apnea, hopefully, you realize just how serious this sleep disorder is for your health. Now, additional evidence suggests just how life-threatening it can be with nearly double the risk of sudden death. 

Discover why sleep apnea is so dangerous for your heart, its role in increasing the risk for sudden death, why getting tested can save your life, and how important sleep apnea treatment is to reduce your risk.  

Why is Sleep Apnea Dangerous?

Sleep apnea is a sleep disorder where your airway becomes partially or completely obstructed while you sleep. Approximately 22 million Americans have sleep apnea, while millions more are likely undiagnosed. 

Many people, including some primary care physicians, are unaware of many of the health implications of obstructive sleep apnea. This is one reason sleep apnea is so underdiagnosed.

“A common misconception is that sleep apnea merely disrupts sleep leading to daytime sleepiness, fatigue, and foggy brain in the morning. Nothing could be further from the truth,” according to Dr. William Noah, Medical Director for Sleep Centers of Middle Tennessee. 

Although sleep apnea can make it impossible to get the quality sleep you need even when getting a full 7-9 hours of sleep, the associated health risks are far more serious. These include diabetes, high blood pressure, and erectile dysfunction (an early warning sign of vascular issues). Obstructive sleep apnea (OSA) is also associated with cardiovascular disease (CVD) morbidity and mortality. 

OSA’s impact on CVD is often highlighted with links to coronary artery disease, stroke, heart attack, increased risk of congestive heart failure, atrial fibrillation, heart failure, and first degree heart block.  

When you have OSA, the obstruction causes a lack of oxygen. That decrease in oxygen saturation when asleep increases oxidative stress— or an imbalance of free radicals and antioxidants in the body. The resulting imbalance can make people with untreated or undiagnosed sleep apnea more vulnerable to conditions like atherosclerosis (a build-up of plaque on the artery walls) and endothelial dysfunction which occurs when blood vessels on the heart narrow and constrict rather than dilate and open.

It’s also important to note that untreated sleep apnea may also reduce the effectiveness of treatments you may be using for other health problems. For instance, treatment of diabetes and high blood pressure are both impacted. This is because the airway obstructions cause spikes in both blood pressure and insulin levels while sleeping. Treating the apneas and hypopneas (partial airway obstructions) reduces or eliminates the spikes during sleep allowing for more effective treatment. 

Check out our additional resource on how sleep apnea can shorten your lifespan or how many people die from sleep apnea each year as a result of cardiovascular events. 

Sudden Cardiac Death and Sleep Apnea

Sudden cardiac death (SCD) is an all too common and devastating event. Globally, cardiovascular disease is the leading cause of mortality, with SCD being the most common manifestation. 

There are few studies looking at the direct connection between OSA and sudden cardiac death. However, there is a growing body of work evaluating sleep apnea as a risk factor with numerous connections highlighted in these recent studies. 

One reason for so little data examining the association between OSA and SCD is because a sleep study is required to derive any incident relationship. Until recently, there wasn’t any research capturing the necessary information for a large group of people with sufficient follow-up. 

This changed with a clinic-based cohort study published by the Journal of the American College of Cardiology. This study included 10,701 adults who underwent a sleep study with a five-year follow-up. It was the first study of its kind to implicate OSA as a potential independent risk factor for SCD. 

Sleep Apnea and Reduced Oxygen Levels During Sleep 

Sleep apnea reduces oxygen saturation in your blood because airflow is restricted. Not only does this cause massive oxidative stress in the body which affects heart health, but according to the study mentioned above, it’s also predictive of sudden death. Specifically, the lowest nighttime oxygen saturation value a patient dropped to was predictive of sudden cardiac death. For every 10% decrease in that oxygen saturation, there was a 14% increase in the risk. 

One other study reported a 2.57-fold increase in the relative risk of nocturnal (nighttime) sudden cardiac death in patients with OSA between midnight and 6 a.m. compared to the general population. This risk increases in proportion with the increasing number of hypopnea events (number of times airflow is restricted) – meaning apnea sufferers with severe obstructive sleep apnea are at higher risk of sudden death. 

The reduced oxygen saturation that occurs when someone has sleep apnea is also believed to cause an over-arousal of your central nervous system to increase airflow. 

Your body’s responses (consciously and subconsciously) are part of a complex relationship between your sympathetic nervous system and the autonomic nervous system. 

Your autonomic nervous system (ANS) is a control system. It regulates bodily functions like digestion, urination, and heart rate. It’s also the system that controls your fight or flight response. 

The sympathetic nervous system (SNS) is one of the divisions of the autonomic nervous system. It’s responsible for priming your body for action, especially when your survival is threatened as it is when oxygen saturation decreases.

Sympathetic nervous system stimulation causes vasoconstriction of blood vessels and it’s responsible for the force and rate that your heart contracts. This sympathetic activation while you’re sleeping will cause an increased heart rate and force of contraction to allow for increased cardiac output to provide your body with oxygenated blood. 

This sympathetic activation during sleep is an important mechanism of cardiovascular morbidity and mortality for anyone with OSA. In other words, the stimulation of the sympathetic nervous system during sleep is a major contributing factor for cardiovascular disease and resulting death.

Although the link between OSA and SCD is complex, recent studies underscore an interaction between them, including new research pointing to the urgency in treating sleep apnea. 

New Research: The Risk of Sudden Death Nearly Doubles with OSA

Adding to the studies connecting sleep apnea and sudden death, Penn State College of Medicine performed a systematic review and meta-analysis of 22 observational studies assessing the association of sudden deaths in individuals with and without OSA. They found that obstructive sleep apnea is associated with both all-cause sudden death and cardiovascular death. 

They reported that an obstructive sleep apnea patient is almost twice as likely to experience sudden death when compared to someone without OSA. As one might expect, severe sleep apnea has the highest risk of mortality. Older age is a significant contributing factor to mortality as well.  

The link between obstructive sleep apnea and sudden cardiac death is complex, which is why it’s so important to check your risk factors and get tested if you suspect you’re suffering from sleep apnea. Snoring, pauses in breath while sleeping, being overweight, and heredity (if your family members were diagnosed) are all signs you should get tested for sleep apnea. 

The Importance of Sleep Apnea Treatment

This new information can seem scary if you or a loved one have obstructive sleep apnea, but this risk can be greatly reduced if the condition is appropriately treated.

Although there are no studies specifically examining the impact of CPAP therapy on sudden cardiac death, there are studies looking at the effects of CPAP treatment on long-term cardiovascular outcomes. One meta-analysis found treatment with CPAP was associated with a significantly lower risk of cardiovascular events in six of the seven studies reviewed.

CPAP, or continuous positive airway pressure, treats sleep apnea by keeping your airways open and providing the body with a constant stream of air to help you breathe thereby preventing reduced oxygen levels in the body. 

CPAP therapy is a safe, accessible, and effective treatment for OSA symptoms, but only if you stay consistent with your treatment and continue to use your CPAP machine.

Lifestyle changes, in addition to CPAP therapy, can also help you relieve symptoms of sleep apnea and heart disease. If you haven’t done so already, consider making these changes for both your sleep health and your heart health:

  • Lose any excess weight that may be putting pressure on your airways
  • Incorporate 30 minutes of moderate exercise into your day
  • Eat a healthy and well-balanced diet
  • Reduce consumption of alcohol and nicotine
  • Practice good sleep habits (here are a few recommended lifestyle changes for better sleep)

When to Consult an Expert

If you think you may have sleep apnea or another sleep disorder, it’s important to reach a sleep expert as soon as possible. If you’re not sure if you’re experiencing sleep disordered breathing or are at risk, try our sleep apnea quiz. You won’t get a diagnosis from this quiz, but it can help you determine if a screening or an evaluation is needed. 

Once you know more about your symptoms, make sure to follow up for evaluation with an accredited sleep center.

A sleep study, the right testing, and proper treatment can make all the difference if you’re suffering from obstructive sleep apnea, and appropriate OSA treatment can make a significant difference with your heart health. Contact the Sleep Centers of Middle Tennessee today so you can get the restful sleep you need each night, and keep your heart healthy in the process.


Gami AS; Olson EJ; Shen WK; Wright RS; Ballman KV; Hodge DO; Herges RM; Howard DE; Somers VK; “Obstructive Sleep Apnea and the Risk of Sudden Cardiac Death: A Longitudinal Study Of 10,701 Adults.” Journal of the American College of Cardiology, U.S. National Library of Medicine,

VK; Gami AS; Howard DE; Olson EJ; Somers. “Day-Night Pattern of Sudden Death in Obstructive Sleep Apnea.” The New England Journal of Medicine, U.S. National Library of Medicine,

Heilbrunn, Emily S, et al. “Sudden Death in Individuals with Obstructive Sleep APNOEA: A Systematic Review and Meta-Analysis.” BMJ Open Respiratory Research, Archives of Disease in Childhood, 1 June 2021,, Jacob N., et al. “Sleep Apnea and Sudden Cardiac Death.” Circulation Reports, U.S. National Library of Medicine,

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