Allows us to better understand your problem
Sleep through the nightFall asleep fasterSleep without pills
More than 34% of middle-aged males and approximately 17% of females have sleep apnea; however, much of the population does not realize that this "disorder of sleep" is gradually damaging their cardiovascular system. Sleep apnea, specifically obstructive sleep apnea (OSA), can be thought of as not just a problem with snoring but as an independent risk factor for life-altering cardiovascular diseases such as heart attack, stroke, and heart failure, which are considered significant health risks.
What is Sleep Apnea?
Obstructive sleep apnea is when the upper airway is temporarily closed off during sleep, resulting in a total absence of breathing (apnea) or substantially decreased breathing (hypopnea). These interruptions, while breathing, will have a ripple effect on a variety of physiological responses over a prolonged time period, thus presenting numerous antecedent stresses to the cardiovascular system over the course of a night.
If researching the severity of sleep apnea, a researcher or cardiovascular professional will observe the apnea-hypopnea index (AHI) number, in other words, the observable times of breathing.
To track the severity of sleep apnea, researchers and cardiovascular professionals will consider the apnea-hypopnea index (AHI), meaning the observable number of times there is a breathing disruption in an hour:
However, new research has demonstrated that just taking into account the AHI does not demonstrate all the cardiovascular risk, as the degree of oxygenated blood saturation, the length of the events, and hypoxic-load or burden each play an equally important role in the overall risk for heart disease development.
The primary mechanism that links sleep apnea and heart disease is intermittent hypoxia, referring to repeated cycles of oxygen deprivation followed by reoxygenation of the tissue. This cycle will produce oxidative stress and activate inflammatory pathways, leading to direct damage to blood vessels and the heart muscle.
We chatted with Dr. Michael Grandner, Sleep Expert and Professor of Neuroscience and Physiological Sciences, about the implied cardiovascular effects of sleep apnea. He notes: "Sleep apnea is a perfect storm of cardiovascular stress from repeated drops in oxygen that trigger fight-or-flight responses throughout the night." The chronic activation, in turn, overwhelms the body's natural repair processes, resulting in collective damage over time.
Each episode of apnea triggers the body's fight-or-flight response and bombards the body with increased amounts of stress hormones, such as adrenaline. This sympathetic activation, in turn, increases heart rate, blood pressure, and constricts blood vessels—and this all happens even during waking hours.
This results in chronic cardiovascular stress. Studies show that people with untreated sleep apnea have increased sympathetic activity even while awake. This creates a 24/7 strain on the heart and blood vessels.
Sleep apnea produces a chronic low-grade inflammatory state by activating inflammatory pathways, mainly nuclear factor-κB (NF-κB) and hypoxia-inducible factor-1 (HIF-1). These pathways significantly increase the production of inflammatory mediators such as C-reactive protein, interleukin-6, and tumor necrosis factor-alpha.
This inflammatory state contributes to an increase in atherosclerosis (hardening of the arteries) and increases the risk of clot formation, both of which are important mechanisms related to heart attacks and strokes. Oxidative stress further damages the inner endothelial layer of blood vessels, reducing their ability to regulate blood flow and blood pressure.
Sleep apnea increases your risk of hypertension by 140% and is now considered to be a leading cause of treatment-resistant high blood pressure. The relationship is significant since sleep apnea is present in 40-80% of people with high blood pressure. Intermittent hypoxia is capable of activating multiple pathways. First, it activates the renin-angiotensin system, which is the primary mechanism by which the body controls blood pressure, and repeatedly increases sympathetic activity, which causes vasoconstriction and increases cardiac workload.
There is evidence that sleep apnea increases the risk of coronary heart disease by 30%. It facilitates atherosclerosis through both chronic inflammation and oxidative stress and increases the risk of acute coronary events through several mechanisms:
The relationship between sleep apnea and heart failure is bidirectional, wherein sleep apnea causes heart failure and heart failure, in turn, exacerbates sleep apnea. Evidence suggests a 140% increased risk of heart failure in people with untreated sleep apnea. Also, repeated increases in blood pressure and heart rate during apneas over time place strain on the heart muscle. The large negative swings in pressure in the thoracic cavity when attempting to breathe in the presence of obstruction increase workload on the heart by increasing left ventricular afterload.
This is particularly concerning for those already experiencing sleep maintenance insomnia.
There is a clear association of sleep apnea with atrial fibrillation (AFib), the most common cardiac arrhythmia. Evidence suggests that the prevalence of sleep apnea in the AFib population ranges from 40-60%, versus the general population.
The mechanistic associations include atrial stretch due to the negative pressure swings developing during apneas, which activate mechanoreceptors and open ion channels promoting arrhythmogenesis, in addition to hypoxia and additional sympathetic activity, further destabilizing rhythm. This often leads to sleep anxiety in affected individuals.
We interviewed Dr. Suzanne Gorovoy, Sleep Expert, Clinical Psychologist, and Behavioral Sleep Medicine Specialist, about the effects of sleep apnea on the cardiac rhythm. She said: "Sleep apnea induces electrical instability in the heart due to hypoxia and pressure changes." It is also why sleep apnea sufferers have palpitations or an irregular heartbeat, particularly at night.
Sleep apnea produces a 60% increased risk of stroke, which is one of the most dangerous cardiovascular consequences. The increased risk is because of several mechanisms:
Sleep apnea isn't just an "older person disease" as many people believe. New research from UT Southwestern found that even risk for cardiovascular disease occurs in sleep apnea patients less than 40 years old.
They studied nearly 10,000 adults with probable OSA, and the episodes revealed that the younger adults had many concerning rates of hypertension, diabetes, and metabolic syndrome. This is particularly concerning with the rise in obesity rates that can closely correlate with sleep apnea conditions and often contributes to sleep deprivation.
Sleep apnea affects men and women differently, from presentation to cardiovascular consequences. Men are more likely to develop sleep apnea, but several studies suggest that women are more likely to experience cardiovascular mortality if they have the disorder.
Women with sleep apnea may exhibit different symptoms, such as insomnia, early-morning headaches, and fatigue, rather than the distinguishing loud snoring. Inadequate diagnosis and treatment of sleep apnea can result in delayed intervention and escalate cardiovascular risk, often contributing to sleep-related anxiety.
We spoke to Dr. Areti Vassilopoulos, Sleep Expert, Pediatric Health Psychologist, and Assistant Professor of Child Psychology, about the gender differences in women regarding sleep apnea, and she stated, "The symptoms women have from sleep apnea frequently are dismissed as stress-related symptoms when they are symptoms related to significant cardiovascular risk." This clearly indicates that we should recognize gender differences in individuals and their presentation of symptoms.
Examples of symptoms that should initiate a sleep apnea evaluation are:
Many of these symptoms overlap with general sleep disorders, making proper evaluation essential.
Certain cardiovascular conditions may raise suspicion for underlying sleep apnea, including:
Polysomnography (sleep study) is a test performed overnight and considered the gold standard for diagnosing sleep apnea, as this test measures breathing patterns, oxygen levels, brain waves, and heart rhythm during sleep. Home sleep apnea tests are often used for relatively uncomplicated sleep apnea cases, but these tests may underestimate severity in a person with cardiovascular disease.
For those concerned about symptoms, consider starting with a self-sleep clinic assessment.
CPAP is the standard of care for patients with moderate to severe obstructive sleep apnea (OSA) as it delivers pressurized air via a mask to maintain the airway patency while sleeping, thus eliminating apneas and hypopneas.
Some cardiovascular benefits of CPAP therapy include the following:
Nonetheless, pivotal clinical studies, including Sleep Apnea Cardiovascular Endpoints (SAVE), have shown mixed results regarding CPAP and/or prevention of cardiovascular events. Thus, effective treatment of sleep apnea also requires patients to consider overall cardiovascular risk factors. This comprehensive approach often includes improving overall sleep quality.
If you are unable to tolerate CPAP therapy, there are alternatives to consider, including:
Some patients find success with natural sleep remedies as complementary approaches.
Because obesity presents a significant risk factor for both OSA and cardiovascular disease, weight loss will improve both conditions. Even a modest weight reduction of 5–10% of your body weight will lead to an improvement in OSA severity and cardiovascular risk factors, often leading to better sleep patterns naturally.
New investigations have suggested that hypoxia burden, or the overall amount of oxygen desaturation during sleep, may offer a more valid prediction of cardiovascular risk than the standard measure of apnea-hypopnea index (AHI). This finding may provide a pathway to treatment based on physiological variation to sleep apnea.
There is an exploration of machine learning algorithms to assess the cardiovascular risk of patients with obstructive sleep apnea (OSA) using electronic medical records, perhaps allowing for earlier intervention to improve risk.
There is an investigation of new treatment approaches that may be more conducive to the inflammatory and oxidative stress pathways that are upregulated by intermittent hypoxia, such as:
The SAVE (Sleep Apnea and Cardiovascular Endpoints) trial was the largest randomized controlled trial on whether CPAP treatment reduces cardiovascular events in patients with cardiovascular disease and sleep apnea.
While there was no statistically significant decrease in the primary composite outcome of cardiovascular death, myocardial infarction, stroke, or hospitalization, there are some interesting takeaways:
These results have sparked further studies to better determine which patients benefit most from sleep apnea treatment and adherence improvements to therapy, often incorporating sleep coaching approaches.
Preventing the onset of sleep apnea is based on modifying risk factors:
In individuals already diagnosed with sleep apnea, preventing cardiovascular consequences will rely on:
Many patients benefit from comprehensive sleep programs that address multiple aspects of sleep health simultaneously.
The strong association between sleep apnea and cardiovascular disease demonstrates the need for integrative care of the patient. Cardiologists should screen patients for sleep disorders, as sleep specialists should assess and manage cardiovascular risks.
It should be clear from this discussion that sleep health is cardiovascular health. Caring for cardiovascular health equals caring for sleep health, because to successfully care for one, you need to evaluate and carefully manage both together. For patients, this means more success through cooperatively coordinated care that pays attention to all aspects of their health.
Recognizing the complex relationship between sleep apnea and heart disease provides both the patient and the healthcare provider the opportunity to step up prevention, early detection, and treatment in a multifaceted way to ultimately protect their quality of sleep and cardiovascular health for many years to come.
If you want more information about sleep health, quality of sleep, and cardiovascular risk, please check out our comprehensive guides to improving sleep health and quality, as well as natural strategies to sleep well. If you think you are experiencing sleep apnea signs, think about taking the self-sleep clinic assessment in order to rate your own symptoms and receive recommendations regarding whether you should consult sleep experts for evaluation and achieve better sleep.
Dr. Shiyan Yeo
Dr. Shiyan Yeo is a medical doctor with over a decade of experience treating patients with chronic conditions. She graduated from the University of Manchester with a Bachelor of Medicine and Surgery (MBChB UK) and spent several years working at the National Health Service (NHS) in the United Kingdom, several Singapore government hospitals, and private functional medicine hospitals. Dr. Yeo specializes in root cause analysis, addressing hormonal, gut health, and lifestyle factors to treat chronic conditions. Drawing from her own experiences, she is dedicated to empowering others to optimize their health. She loves traveling, exploring nature, and spending quality time with family and friends.
