Understanding sleep apnea goes far beyond a sleepy day at your desk and some irritability with your loved ones. While research has long proven that sleep apnea can greatly impact your daily quality of life, evidence is mounting that the risks of sleep apnea and heart disease (among other conditions) is real. Here’s what we’ve learned about sleep apnea and cardiovascular disease.
Can sleep apnea cause heart problems?
The numbers may be conservative, but an estimated 25 million people in the U.S. suffer from one of three types of sleep apnea. Obstructive sleep apnea is the most common. In this type of sleep apnea, the soft tissues of the throat relax, causing the sleeper’s airway to become blocked.
Central sleep apnea is rare and is caused by the central nervous system “forgetting” to reflexively breathe at night. Complex sleep apnea is the most rare form, combining the two other types.
Common symptoms of sleep apnea include:
- Daytime fatigue
- Inability to focus
- Moodiness and irritability
- Morning headache and migraine
- Increased sweating at night (unrelated to other conditions)
- Sexual dysfunction
While these symptoms are nothing to brush off, there is mounting evidence as to the relationship between sleep apnea and heart disease, including heart palpitations and enlarged heart.
Researchers at Harvard note that sleep apnea, also referred to as sleep disordered breathing, also occurs at the following rates for people with other serious conditions:
- Cardiovascular disease: 47 to 83%
- Heart failure, AFIB, and stroke: 12% to 53%
- Hypertension: 35%
These percentages only tell the beginning of the story. Here’s the rest.
Sleep apnea and AFIB
Atrial fibrillation (AFIB) is the most common type of irregular heartbeat (cardiac arrhythmia). In the U.S., nearly three million people have this condition. Sleep apnea and irregular heartbeat are often comorbid conditions. As with many other serious conditions associated with sleep apnea, the relationship between these two is bidirectional: each makes the other worse (or intensifies already present symptoms).
There are several reasons why sleep apnea intensifies the risk and symptoms of AFIB. As sleepers suffer apneas and loss of oxygen repeatedly throughout the night, the systems of the body remember this oxidative stress during the day. Because of this:
- Inflammation increases (measured by the presence of a C-reactive protein)
- Heart rate increases
- Atrial walls thicken
All of these actions begin or are intensified by the regular lack of oxygen and the body’s systemic response.
Sleep apnea and heart failure
While in most cases having a “big heart” is a good thing, when it comes to sleep apnea and enlarged heart, the consequences can be fatal. The stress placed on the heart every night actually causes the heart to become enlarged over time (it is, after all, a muscle). And, an enlarged heart can lead to heart failure.
It can be challenging, though, to see which condition has more influence.
Both sleep apnea and heart issues have similar symptoms, hormonal responses, and biological markers. What is certain, though, is that sleep apnea is present in nearly 60% of people experiencing heart conditions. Sleep apnea and heart disease are inextricably linked. Because of this, it makes sense to address both for the best chance at successful overall treatment.
Sleep apnea and hypertension
Remember that oxidative stress that the body can’t forget during the day? It also affects a sleeper’s risk for developing hypertension (high blood pressure).
Sleep apnea prompts the release of endothelin, a substance that causes blood vessels to constrict. When a sleeper wakes, endothelin may be continuously released, even during the day, as a result of the body’s memory of hypoxia (lack of oxygen). This continual release can damage the blood vessels and increase the chances of hypertension.