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Untreated sleep apnea and high blood pressure: Risks, causes, and correlations

There are people who have been diagnosed with some form of sleep apnea who have not taken the critical step of starting therapy for it.

They may mistakenly believe they can “live” with their sleep apnea, or they may be intimidated by treatment options (or not know about their options at all).

Unfortunately, if they don’t treat their sleep apnea, they are practically guaranteeing that they will either develop high blood pressure ( hypertension ) as a result, or aggravate a preexisting case of it.

What makes this even worse is that both sleep apnea and hypertension are silent conditions, in that it can be impossible for some people to know they have either without a full medical assessment.

How is sleep apnea related to high blood pressure?

When you have a respiratory event called an apnea (or a pause in breathing), you risk depriving your bloodstream of necessary oxygen.

Apneas that repeat over the course of the night can result in a problem with developing significantly lower levels of oxygen in the blood over several hours.This is called hypoxia .During hypoxic events, the brain receives chemical messages alerting it to these dangerous reductions in blood oxygen (called desaturations ).

As its response to these desaturations, the brain sends signals to the nervous system to tighten up the blood vessels in order to speed up blood flow. This is called vasoconstriction.

Why does the brain do this? It needs adequate oxygen to function properly; the quicker it can receive necessary oxygen, the better. The problem with this is that, in doing so, the brain raises blood pressure by as much as 20 percent. Normally, most people experience a blood pressure drop of between 10 and 20 percent during sleep, not an increase .

Another side effect of hypoxia is that the brain instructs the body to awaken briefly in order to provoke the respiratory system to start breathing again. This involves flooding the bloodstream with stress hormones, such as epinephrine and adrenaline, to awaken in order to start breathing again.This is one of the main reasons why sleep fragmentation occurs; it is also one of the reasons why inadequate sleep is also connected to hypertension.

This stress response also speeds up the heart rate (the pulse), leading to added stress on the heart muscle.Over time, blood pressure rises to resting levels that are higher than normal, no matter what time of day, for people with untreated sleep apnea.This is because the walls of the blood vessels cannot relax like they are normally meant to.

Instead, people with perpetual desaturation experience perpetual stress responses that leave the blood vessels in a constant state of vasoconstriction, even during the waking state.Eventually, those ranges of blood pressure will increase during the day to become that person’s “new normal.”

Why untreated sleep apnea threatens heart health

We should all recognize by now that high blood pressure is the villain behind many chronic and dangerous health problems such as heart disease, heart failure, vascular disease, and stroke.

The statistics are compelling when it comes to people with apnea who do not treat their sleep disorder.

The American Association for Respiratory Care estimates that at least half of those who suffer from sleep-disordered breathing, like obstructive sleep apnea (OSA), will develop hypertension.

Also, nearly 6 out of 10 men with severe OSA are likely to develop congestive heart failure, compared to men who do not have OSA, says one National Sleep Foundation study.Older men with moderate to severe OSA were also found to be more likely to develop coronary heart disease than their mild- or non-OSA peers.

The problem of atrial fibrillation

When untreated, OSA also causes problems with the heart’s electrical processing that can cause it to race at a stress-induced pace, night after night, eventually damaging the cardiac”engine” and causing arrhythmias to develop, such as atrial fibrillation (AFib).

AFibis a condition of the pacing of the heart that is also caused, in part, by high blood pressure.

Why is AFib a problem? If left untreated, it is well known to be a leading cause of stroke.

According to research published in the Journal of the American College of Cardiology , 50 percent of all AFib patients also have OSA (while only 33 percent of patients without AFib haveOSA).AFib and OSA share traditional risk factors, such as obesity, hypertension, and diabetes, but AFib is more highly associated with preexisting OSA than with any of these other chronic health problems.

The good news

If you suffer from both sleep apnea and high blood pressure, you may find that treating your sleep-disordered breathing may reverse elevated blood pressure readings as well as reduce your risk factors for other cardiovascular problems.

While treatment depends on the severity of one’s sleep apnea, the two most common approaches to therapy oral appliances and continuous positive airway pressure (CPAP) therapy have been shown by extensive research to not only reduce the severity of OSA, but to improve blood pressure readings, as well.

To fully assess your risk for sleep apnea, your best bet is to see a sleep specialist, undergo a sleep study to evaluate your respiratory patterns and vital signs during sleep, and identify any underlying sleep-breathing disorders and their severity.

OSA is eminently treatable, which is good news for people with both OSA and hypertension, because treatment for their OSA may also treat their high blood pressure… and reduce their risk for developing serious cardiovascular problems down the road.


American Association of Respiratory Care
Journal of the American College of Cardiology
Journal of the American Medical Association
National Sleep Foundation
New England Journal of Medicine
Stanford Center for Sleep Sciences and Medicine

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