Does Sleep Apnea Cause High Blood Pressure?
It’s been well established that people with heart disease and high blood pressure have a high percent chance of also having sleep apnea (1).
But does apnea cause high blood pressure? Or is it the other way around?
There’s no known mechanism that explains how elevated blood pressure could directly cause sleep apnea. Apnea is typically caused by weight, specifically too much fat stored in certain regions of the neck area.
In other words, it really looks like sleep apnea causes high pressure, and not the other way around.
Let’s quickly go through a summary of research supporting this conclusion.
Research on Sleep Apnea and High Blood Pressure
It’s hard to study a question like that because you can’t easily induce apnea or high blood pressure directly in subjects.
But one way to find an answer is to look at how treatment for one of the symptoms affects the others.
The most common treatment to reduce apneas during sleep is using continuous positive airway pressure (CPAP).
One study looked at the effects of using CPAP treatment for 12 weeks on patients with both obstructive sleep apnea (OSA) and hypertension (high blood pressure) (2). They found:
CPAP treatment for 12 weeks compared with control resulted in a decrease in 24-hour mean and diastolic blood pressure and an improvement in the nocturnal blood pressure pattern.
While it wasn’t a huge amount, there was a statistically significant decrease in blood pressure as a result of the treatment.
Another study had a similar approach and had the same conclusion (3):
Sleep apnea elicits increases in blood pressure and endothelin-1, with reductions in both after treatment (CPAP)
In other words, it does appear that apneas are the cause of high blood pressure.
SummaryResearch has shown that reducing the frequency of apnea events through CPAP treatment also reduces blood pressure. While there may be other factors leading to high blood pressure, it does appear that sleep apnea does cause an increase in blood pressure by itself.
How Much Does Sleep Apnea Raise Blood Pressure?
It’s important to understand how big of a problem sleep apnea is in causing high blood pressure.
A population-based study found that (4):
Mean blood pressures were significantly higher among participants with sleep apnea compared with those without (131/80 ±1.7/1.1 mm Hg compared with 122/75 ±1.9/1.2 mm Hg during wakefulness and 113/66 ±1.8/1.1 mm Hg compared with 104/62 ±2/1.3 mm Hg during sleep, respectively).
Whether asleep or awake, those with sleep apnea have an average blood pressure about 10% higher than those without sleep apnea.
And while 10% doesn’t seem a lot by itself, it’s enough to push a lot of people over the threshold where blood pressure becomes dangerous.
The NIH defines a normal blood pressure as (5):
- Systolic (first number) under 120
- Diastolic (second number) under 80
A significant number of people will go from a healthy blood pressure to a high blood pressure with a 10% increase in either number.
High blood pressure leads to damage in arteries, which can then cause damage to the heart, brain, kidneys, eyes, and more.
Will CPAP Treatment Fix High Blood Pressure?
As we saw in the research, CPAP treatment is often enough to lower blood pressure.
So is that enough by itself?
Not everyone will respond to CPAP the same way, and apnea is often only one cause of high blood pressure.
In most cases, weight is also an issue for both apnea and high blood pressure, and CPAP will not fix the underlying problem.
Sleep apnea also causes weight gain, and studies have shown that CPAP doesn’t improve weight (and sometimes leads to even more weight gain).
This is why doctors typically prescribe a treatment plan for those with apnea that focuses on weight reduction. Even though CPAP may also be recommended to manage symptoms, it ideally shouldn’t be needed for the long-term if the underlying issues are fixed.
Medical Disclaimer: The information on SnoozeUniversity.com is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.