Can Untreated Sleep Apnea Kill?

July 1, 2022

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An estimated 2–9 percent of adults in the US experience sleep apnea, with many additional cases that likely go undiagnosed. Even more disquieting is that many who suffer from sleep apnea aren’t aware of the serious risks and dangers associated with the sleep disorder.

Is there any real danger associated with sleep apnea? The alarming reality is that, yes, if left untreated, sleep apnea is associated with a host of health conditions and could even lead to death, both directly and indirectly.2,9 The good news is there are proven ways to successfully treat sleep apnea, reduce its long-term effects, and prevent death.

Continue reading to learn why sleep apnea is dangerous, what causes it to be fatal, and how to reduce the risk of death from obstructive sleep apnea (OSA).

Why is sleep apnea dangerous?

Sleep apnea is a sleep-breathing disorder in which breathing stops and starts repeatedly during sleep.8 OSA occurs when the tissue in the back of the throat relaxes too much and collapses, blocking the airway. The following are common symptoms of OSA:

  • Snoring
  • Daytime fatigue or sleepiness
  • Restlessness while sleeping
  • Dry mouth or sore throat in the morning
  • Waking up suddenly, choking or gasping for air
  • Trouble concentrating, forgetfulness, or crankiness
  • Depression or anxiety
  • Night sweats
  • Sexual dysfunction
  • Headaches7,8

Not only are these unpleasant symptoms to experience, but sleep apnea is also associated with a number of other conditions that put a person’s health at risk. For instance, those who suffer from OSA are shown to have higher rates of cardiovascular diseases, respiratory diseases, metabolic disorders, chronic liver disease, acid reflux, peptic ulcer disease, anxiety disorders, depression, and insomnia.2,8,9 

Is OSA likely to be fatal?

For patients with comorbidities such as hypertension, developing OSA can increase the risk of adverse health outcomes.2  The risk depends on the OSA severity level, which is based on the number of episodes of blockage that occur per hour during sleep.8 The number of episodes is measured by the apnea-hypopnea index (AHI), which is the total number of episodes of apnea and hypopnea occurring during sleep divided by the hours of sleep time. If breathing stops fewer than five times per hour, this is considered normal. If breathing stops five times or more per hour but fewer than 15, it is considered mild. If breathing stops 15 times or more per hour but fewer than 30, it is considered moderate. If breathing stops more than 30 times per hour, it is considered severe.8 As OSA severity increases, the risk of health complications increases as well.2

If left untreated, severe sleep apnea can be fatal.10 In one study, researchers followed 1,522 participants for 18 years. They found that those with severe sleep apnea had three times the risk of death due to any cause compared to those without sleep apnea, controlling for age, sex, and body mass index.10

The risk of death can increase directly from OSA or indirectly through its associated health conditions:


OSA and death can be directly related. “Sleep apnea can directly cause death by a person’s breathing being infrequent enough to create immediate tissue ischemia (tissue death from lack of oxygen) in the heart and/or brain, resulting in a fatal heart attack or stroke,” says Jenna Liphart Rhoads, RN, PhD.

In addition to sudden strokes or heart attacks, OSA is also associated with cardiac arrest, which is when the heart suddenly stops beating.6,9 OSA creates stressors on the heart, such as activation of the fight-or-flight response (sympathetic nervous system), lowered oxygen levels, inflammation, unhealthy changes in blood vessels, and pressure changes in the chest, which can all increase the chance of cardiac arrest.6,9 A person experiencing cardiac arrest can die within minutes if there is no intervention, which is likely to be the case if occurring during sleep.1 


OSA can also increase the risk of death indirectly through a variety of related medical conditions, including heart disease, thyroid disease, hypertension, and type 2 diabetes.7,8 These conditions all put a person’s health at risk and are associated with higher death rates. However, additional studies are needed to prove causation for some comorbidities, particularly for sudden cardiac death (SCD).1,9

How can patients reduce their risk of death from OSA?

Although there are serious risks associated with OSA, patients can significantly reduce their risk of health complications and death through sleep apnea treatment.9 For patients with comorbidities, early OSA screening is especially important and recommended by the American Heart Association.5,9  One study found patients with heart failure who were tested, diagnosed, and treated for OSA had better survival rates compared to those who were not treated.5

Generally, a combination of treatments is the best option for patients.4,79 Here are some of the common ways to treat OSA.4,79

Lifestyle Changes

A large factor in the connection between sleep apnea and associated health conditions is obesity. Fortunately, efforts to lose weight through healthy eating and exercise can reduce the symptoms of OSA.8 Just a 10 percent loss of weight can reduce AHI by 26 percent. However, 20–40 percent of individuals with OSA are not obese, and OSA symptoms may not resolve after weight loss.6 Other lifestyle changes—like cutting out alcohol, smoking, and sedative medications, or changing sleeping position—may naturally reduce the symptoms of OSA.7,8

CPAP Machines

Continuous positive airway pressure (CPAP) machines deliver continuous air through a mask while a patient sleeps. The air delivered is at a slightly higher pressure than normal, which helps keep the airway open, preventing snoring and interrupted breathing. CPAP is the most common form of treatment for sleep apnea and is effective in reducing the negative health effects of OSA, but many find this method noisy and uncomfortable.4  Two studies, the Sleep Heart Healthy Study and a 30-year study of OSA, both found CPAP use in severe OSA patients lowered mortality rates (42 percent).3,9

Oral Appliances

Oral appliances can be an effective treatment option for people with mild-to-moderate sleep apnea and patients who are not compliant with CPAP.4,9 There are multiple types of oral appliances, but the most common type is designed to bring the jaw forward and open the throat, thereby relieving symptoms of OSA.


Surgery is a last-resort option for severe cases of sleep apnea when other treatment options have failed. Surgical options can include tissue removal, tissue shrinkage, jaw repositioning, implants, nerve stimulation, and tracheostomy (creating a new air passageway).8

Obstructive sleep apnea (OSA) should not be treated lightly. Depending on the severity, it can lead to serious health issues and, in some cases, prove fatal. Fortunately, there are proven methods for effectively treating OSA that can keep those who suffer from this sleep condition safe. For healthcare professionals, providing early screening and testing can help patients live healthier and longer lives. If you are experiencing symptoms of OSA, don’t wait to get tested and treated. You will avoid the risk of harmful health conditions, and it can ultimately save your life.

  1. Blackwell, J. N., Walker, M., Stafford, P., Estrada, S., Adabag, S., & Kwon, Y. (2019). Sleep apnea and sudden cardiac death. Circulation Reports, 1(12), 568–574. doi:10.1253/
  2. Bonsignore, M. R., Baiamonte, P., Mazzuca, E., Castrogiovanni, A., & Marrone, O. (2019). Obstructive sleep apnea and comorbidities: a dangerous liaison. Multidisciplinary Respiratory Medicine, 14(1). doi:10.4081/mrm.2019.10
  3. Dodds, S., Williams, L. J., Roguski, A., Vennelle, M., Douglas, N. J., Kotoulas, S.-C., & Riha, R. L. (2020). Mortality and morbidity in obstructive sleep apnoea-hypopnoea syndrome: results from a 30-year prospective cohort study. ERJ Open Research, 6(3), 00057–02020. doi:10.1183/23120541.00057-2020
  4. Francis, C. E., & Quinnell, T. (2021). Mandibular advancement devices for OSA: An alternative to CPAP? Pulmonary Therapy, 7(1), 25–36. doi:10.1007/s41030-020-00137-2
  5. Javaheri, S., Caref, E. B., Chen, E., Tong, K. B., & Abraham, W. T. (2011). Sleep apnea testing and outcomes in a large cohort of Medicare beneficiaries with newly diagnosed heart failure. American journal of respiratory and critical care medicine, 183(4), 539–546.
  6. Javaheri, S., Barbe, F., Campos-Rodriguez, F., Dempsey, J. A., Khayat, R., Javaheri, S., & Somers, V. K. (2017). Sleep apnea: Types, mechanisms, and clinical cardiovascular consequences. Journal of the American College of Cardiology, 69(7), 841–858. doi:10.1016/j.jacc.2016.11.069
  7. Slowik, J. M., & Collen, J. F. (2022). Obstructive Sleep Apnea. In StatPearls. StatPearls Publishing.
  8. Strohl, K. P. (n.d.). Obstructive Sleep Apnea. Retrieved June 2, 2022, from Merck Manuals Professional Edition website:
  9. Yeghiazarians, Y., Jneid, H., Tietjens, J. R., Redline, S., Brown, D. L., El-Sherif, N., & Somers, V. K. (2021). Obstructive sleep apnea and cardiovascular disease: A scientific statement from the American heart association. Circulation, 144(3), e56–e67. doi:10.1161/CIR.0000000000000988
10. Young, T., Finn, L., Peppard, P. E., Szklo-Coxe, M., Austin, D., Nieto, F. J., & Hla, K. M. (2008). Sleep disordered breathing and mortality: eighteen-year follow-up of the Wisconsin sleep cohort. Sleep, 31(8), 1071–1078. doi:10.5665/sleep/31.8.1071