Sleep apnea and bradycardia

We discussed the crossover between sleep apnea and bradycardia in our post on sleep apnea and infants. Here, we’ll go into more detail about the connection between these two health conditions.

First of all: What is bradycardia? It may not be a term you hear every day, but bradycardia is often associated with sleep apnea in medical diagnoses and research studies.¹ That makes it of natural interest to anyone exploring the causes of, and solutions to, sleep apnea.

Often (but not always) associated with sleep apnea in infants, bradycardia is a medical term that means a slow heart rate, which can apply to people of all ages. The American Heart Association (AHA) defines bradycardia as a heart rate of less than 60 beats per minute, but adds that what’s “too slow” for each individual depends on age and the physical condition you’re in.²

“Physically active adults often have a resting heart rate slower than 60 BPM but it doesn’t cause problems,” the AHA article adds. “Your heart rate may fall below 60 BPM during deep sleep.”

Sleep apnea and bradycardia: The cardiovascular connection

So what’s the connection between sleep apnea and bradycardia? The Mayo Clinic lists obstructive sleep apnea as a potential cause for bradycardia due to its tendency to interrupt your body’s sleep patterns.³ A slow heart rate can mean you’re not getting enough oxygen, and failure to get enough oxygen is symptomatic of sleep apnea, a condition that causes you to continually wake up throughout the night because of obstructed breathing.

In a broader sense, bradycardia is a condition affecting the heart, and sleep apnea has a well-known association with heart (i.e., cardiovascular) conditions.^{4 5} Numerous studies have been published that support that connection; a 2007 study in the European Respiratory Journal stating that “considerable evidence is available in support of an independent association between [OSA] and cardiovascular disease” is a good example.⁶

Sleep apnea and bradycardia: The pediatric connection

However, the connection between sleep apnea and bradycardia also commonly refers to apnea of infancy, or the specific type of sleep apnea common among babies.

Pediatrics, the official journal of the American Academy of Pediatrics, defines apnea of infancy as “an unexplained episode of cessation of breathing for 20 seconds or longer, or a shorter respiratory pause associated with bradycardia, cyanosis, pallor, and/or marked hypotonia.”⁷

“Most infants have bradycardia for the same reasons they have apnea,” according to the Emory University School of Medicine. “And often bradycardia results from the baby having apnea. But other medical problems can sometimes be the cause; therefore, babies who have these episodes need to be evaluated.”⁸

The Emory article goes on to list the following possible causes of sleep apnea and bradycardia in infants:

• Infection. This is “a fairly common cause and is often looked for if a baby develops apnea.”
• Low blood oxygen. Because it means a low heart rate, bradycardia can cause oxygen deprivation.
• Airway problems. This includes blockages in the nose or breathing airway, including those caused by mucous.
• Environmental factors. Emory defines these as high or low body temperature, or “excessive handling of a very premature infant.”
• Premature birth. This is often classified as apnea of prematurity.

If an infant does have sleep apnea and bradycardia, what’s the treatment? That often depends on what the specific cause is; for instance, if the cause is infection, that will require a different treatment than a breathing blockage. See last week’s apnea of infancy article for more details.