Sleep apnea is a serious sleep disorder in which breathing can repeatedly stop and start. If you snore loudly and feel tired even after getting a full night’s sleep, it is a good idea to get yourself checked for sleep apnea. A narrowed or blocked airway prevents air from reaching the lungs, usually causing a person to start snoring loudly or even gasp for air while sleeping. These pauses in breathing tend to occur at least a few times in a night, or sometimes in severe cases, they may occur more than once in every two minutes during sleep.
Snoring can keep you and anyone else who sleeps in the same room as you awake, ruining the sleep cycle and daily rhythm and, in some cases, may even harm your relationships. However, more than just being a common annoyance, snoring can actually have life-threatening consequences if left unchecked. Patients with a certain type of sleep apnea have an increased prevalence of many cardiovascular risk factors, including type 2 diabetes mellitus and hypertension. All this is known to increase the risk of cardiovascular disease in people with sleep apnea.
Read on to find out everything about sleep apnea in cardiovascular diseases.
What is Sleep Apnea?
Sleep apnea is a type of sleep disorder in which a person repeatedly stops and starts breathing during their sleep. A blocked or narrowed airway is usually responsible for not getting enough air in the lugs, which causes a person to snore loudly or even gasp for air. These pauses in breathing that occur can happen a couple of times in a night, or in severe cases, it can even happen more than once in every two minutes during sleep.(1, 2, 3)
There are three main types of sleep apnea:
- Obstructive sleep apnea, which is the more common type of sleep apnea that occurs when the muscles of the throat relax during sleep.(4)
- Central sleep apnea, which occurs when the brain stops sending proper signals to the muscles that control breathing.(5)
- Complex sleep apnea syndrome, also known as treatment-emergent central sleep apnea, which occurs when a person has both central sleep apnea and obstructive sleep apnea.(6)
It is estimated that around 34 percent of men and 17 percent of women live with obstructive sleep apnea.(7) Researchers also estimate that over 80 percent of cases of moderate to severe obstructive sleep apnea remain undiagnosed.(8)
This means that there are millions of people living with many of the consequences of sleep apnea, experiencing common symptoms like disrupted sleep, daytime sleepiness, trouble focusing, and chronic headaches without knowing they have a sleep disorder. And it is essential to realize that the effects of sleep apnea go beyond just feeling sleepy and unfocused during the day. Repeated pauses in your breathing can deprive the lungs of essential oxygen and cause a lot of stress on the body. Sleep apnea is also associated with a huge variety of serious health consequences, which include coronary heart disease, stroke, heart failure, and an irregular heartbeat.(9)
Sleep Apnea and Cardiovascular Disease
According to the World Health Organization, cardiovascular disease is the leading cause of death in the world.(10, 11) There are several behaviors that increase the risk of cardiovascular disease, including not exercising enough, drinking too much alcohol, eating an unhealthy diet, and smoking. There are also many health conditions that increase the risk of heart disease, including high cholesterol levels, high blood pressure, diabetes, and obesity.(12)
If left untreated, sleep apnea can also drastically increase the risk of cardiovascular disease and heart arrhythmias. It is estimated that patients with sleep apnea are nearly two to four times more likely to develop heart arrhythmias or abnormal heart rhythms than people without this condition. Sleep apnea increases the risk of coronary heart disease by 30 percent and the risk of heart failure by a whopping 140 percent.(13)
Is There A Link Between Sleep Apnea, Cardiovascular Disease, and Obesity?
Research has shown that obesity also plays an important role in the development of both sleep apnea as well as cardiovascular disease. It is important to remember that sleep apnea alone, regardless of whether you are obese or not, can, of course, increase the risk for cardiovascular disease. Obesity and sleep apnea independently also increase the risk of various heart conditions that adversely affect the heart health, such as hypertension (high blood pressure), cholesterol levels, and diabetes.(14, 15, 16)
Obesity is one of the most common causes of sleep apnea, usually because of the large deposits of fat in the neck that cause blockage or narrowing of the upper airway when you sleep.(17) Researchers have discovered that even a ten percent increase in a person’s body weight can increase the risk of obstructive sleep apnea by nearly six times.(18) While almost 60 to 90 percent of people with sleep apnea have been found to also have obesity, just about 30 percent of people who have been diagnosed with obesity actually have sleep apnea.(19)
Cardiovascular Disease and Sleep Deprivation
Fragmented or insufficient sleep is very common in people with sleep apnea, and the fact is that regularly missing sleep can adversely affect your heart.(20) One of the biggest roles that sleep plays in your body is that it allows the body to rest and recover. Your blood pressure and heart rate both decrease when you are sleeping as breathing becomes more stable and regular. Not getting sufficient sleep due to conditions like obstructive sleep apnea means you are not giving your heart and the entire cardiovascular system this very important time to recover and rest. Chronic sleep deprivation has been linked to a higher risk for heart disease, hypertension, heart attacks, stroke, and many other diseases.(21)
Impact of Sleep Apnea on the Cardiovascular System
Sleep apnea has a direct effect on your cardiovascular system. The repetitive pauses in breathing that happens in people with sleep apnea put a lot of stress on the heart and can even potentially damage not just the heart but the entire cardiovascular system. While studies are still ongoing on the various ways in which sleep apnea affects the cardiovascular system, leading to cardiovascular disease, researchers have suggested several biological pathways, as discussed below.
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Activation of the Sympathetic Nervous System
Every time a person with sleep apnea stops breathing, it causes the level of oxygen in the blood to fall.(22) As your body gets deprived of oxygen for that small amount of time, specialized cells known as chemoreceptors detect these minute changes and activate the sympathetic nervous system to respond. The sympathetic nervous system is a part of the nervous system, and it is responsible for reacting to any kind of dangerous or stressful situation. The sympathetic nervous system triggers the body, causing it to gasp for air, or it can even force a person to wake up and breathe.
The sympathetic nervous system also responds to a fall in oxygen levels by narrowing the blood vessels and increasing your blood pressure and heart rate. As the pauses in breath continue through the night, there are repetitive changes in blood pressure and heart rate, which may eventually lead to hypertension or even worsen existing hypertension or heart problems.
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Oxidative Stress
After every pause in breathing in, a person with sleep apnea they are able to inhale once again successfully. This inhaling brings the much-needed oxygen back into the blood, lungs, and body tissues. However, frequent changes in oxygen levels put a lot of stress on the body, known as oxidative stress. Oxidative stress can cause systemic inflammation, as well as many types of physiological and neurochemical reactions that are known to increase the risk of cardiovascular disease.(23, 24)
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Changes in Pressure inside the Chest
When a person suffers from obstructive sleep apnea, and they attempt to breathe, they inhale against a constricted or closed upper airway. These forced and unsuccessful inhalations can cause a lot of changes in pressure inside the chest cavity. Over a period of time, these repetitive changes in the intrathoracic pressure can cause damage to the heart. Frequent intrathoracic pressure changes can lead to problems with blood flow to the heart, atrial fibrillation (irregular and rapid heartbeat), and sometimes even heart failure.
Conclusion: Treating Sleep Apnea to Reduce the Risk of Cardiovascular Disease
Talk to a doctor about sleep apnea to keep your heart safe. If you are diagnosed with sleep apnea, there are several effective treatments that may include:
- Lifestyle changes
- Mouth and throat exercises
- Positive airway pressure (PAP) devises
- Mouthpieces and oral appliances
- Surgery
Developing a healthy bedtime routine and exercising regularly can also help you get a good night’s sleep. By being careful and managing your sleep apnea, you can reduce the risk of heart disease.
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- Javaheri, S., Barbe, F., Campos-Rodriguez, F., Dempsey, J.A., Khayat, R., Javaheri, S., Malhotra, A., Martinez-Garcia, M.A., Mehra, R., Pack, A.I. and Polotsky, V.Y., 2017. Sleep apnea: types, mechanisms, and clinical cardiovascular consequences. Journal of the American College of Cardiology, 69(7), pp.841-858.
- Kapur, V., Blough, D.K., Sandblom, R.E., Hert, R., de Maine, J.B., Sullivan, S.D. and Psaty, B.M., 1999. The medical cost of undiagnosed sleep apnea. Sleep, 22(6), pp.749-755.
- Drager, L.F., McEvoy, R.D., Barbe, F., Lorenzi-Filho, G. and Redline, S., 2017. Sleep apnea and cardiovascular disease: lessons from recent trials and need for team science. Circulation, 136(19), pp.1840-1850.
- 2022. [online] Available at: <https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm> [Accessed 17 July 2022].
- Who.int. 2022. Cardiovascular diseases (CVDs). [online] Available at: <https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)> [Accessed 17 July 2022].
- 2022. [online] Available at: <https://www.cdc.gov/heartdisease/risk_factors.htm> [Accessed 17 July 2022].
- Jean-Louis, G., Zizi, F., Brown, D.B., Ogedegbe, G., Borer, J.S. and McFarlane, S.I., 2009. Obstructive sleep apnea and cardiovascular disease: evidence and underlying mechanisms. Minerva pneumologica, 48(4), p.277.
- Escobar, E., 2002. Hypertension and coronary heart disease. Journal of human hypertension, 16(1), pp.S61-S63.
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- Ramar, K. and Caples, S.M., 2010. Cardiovascular consequences of obese and nonobese obstructive sleep apnea. Medical Clinics, 94(3), pp.465-478.
- Pillar, G. and Shehadeh, N., 2008. Abdominal fat and sleep apnea: the chicken or the egg?. Diabetes care, 31(Supplement_2), pp.S303-S309.
- Grandner, M.A., Alfonso-Miller, P., Fernandez-Mendoza, J., Shetty, S., Shenoy, S. and Combs, D., 2016. Sleep: important considerations for the prevention of cardiovascular disease. Current Opinion in Cardiology, 31(5), p.551.
- Yuan, R., Wang, J. and Guo, L.L., 2016. The effect of sleep deprivation on coronary heart disease. Chinese Medical Sciences Journal, 31(4), pp.247-253.
- Goldberger, J.J., Cain, M.E., Hohnloser, S.H., Kadish, A.H., Knight, B.P., Lauer, M.S., Maron, B.J., Page, R.L., Passman, R.S., Siscovick, D. and Stevenson, W.G., 2008. American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society scientific statement on noninvasive risk stratification techniques for identifying patients at risk for sudden cardiac death: a scientific statement from the American Heart Association Council on Clinical Cardiology Committee on Electrocardiography and Arrhythmias and Council on Epidemiology and Prevention. Circulation, 118(14), pp.1497-1518.
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