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Sleep Apnea and Hypertension: Are They Linked?

Written by Dr. Sintayehu Abebe on Fri, 11 November 2022

Key Highlights

  • Sleep apnea is a serious sleep disorder that occurs when your breathing stops and starts while you are asleep. If it goes untreated, it can cause loud snoring, daytime tiredness, or more serious problems like heart trouble or high blood pressure.
  • Treatment of OSA with nasal continuous positive airway pressure (CPAP) abolishes apneas, thereby preventing intermittent arterial pressure surges and restoring the nocturnal "dipping" pattern.
  • Because even small decrease in arterial pressure can contribute to reducing cardiovascular risk, screening for OSA is an essential element of evaluating patients with hypertension.
  • CPAP treatment also has modest beneficial effects on daytime blood pressure.
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Do you find yourself tossing and turning, snoring, and experiencing difficulty in breathing at night? Many people who suffer from obstructive sleep apnea (OSA) wake up, not feeling rested from the night before, which can snowball into additional unwanted side effects.

It is now well known that obstructive sleep apnea (OSA) is one of the common secondary causes of blood pressure (BP) elevation, and there is a deep connection between sleep apnea and hypertension.

What is Sleep Apnea

Obstructive sleep apnea or sleep apnea is a respiratory disorder that occurs in both children and adults. Those who exhibit this apnea, experience either complete or partial collapse of the upper airway during sleep. This makes it hard to breathe, and can be very disruptive towards a full night's sleep, while also disturbing your bed partner. It's analogous to breathing through a straw. When you're awake, it is not so difficult as you are aware and you can increase your breathing rate. However, at night you do not have this same compensatory mechanism, so the apnea wakes you up. Obstructive sleep apnea most frequently affects older men but can affect women and children as well.

How Common is Sleep Apnea

Obesity, aging, smoking and alcohol intake are the risk factors for OSA. (OSA) syndrome is the most common sleep-related breathing disorder worldwide. The prevalence of symptomatic OSA in middle-aged men and women is 4.1-7.5% and 2.1-3.2%, respectively.

Risk factors for Sleep Apnea 
 

Asia is a heavily populated continent, with some groups living in an underdeveloped environment. The lowest snoring prevalence of 4.6% was reported in Thailand and the highest prevalence of 59.1% was in Taiwan.

The study from Thailand included a much higher number of women and the population was younger than that in the study from Taiwan/China. The lowest prevalence of witnessed apneas was 2.6% in Taiwan, and the highest was 15.2% in Malaysia.

Signs & Symptoms of Sleep Apnea

Signs & Symptoms of Sleep Apnea

You usually won't notice your first symptoms of obstructive sleep apnea. The most common signs and symptoms are:

  • Snoring
  • Fatigue or sleepiness during the day
  • Restlessness while sleeping or waking up constantly in the night
  • Dry mouth or sore throat when you wake up
  • Waking up suddenly after gasping or choking
  • Trouble concentrating, forgetfulness, or crankiness
  • Depression or anxiety
  • Constant urge to urinate at night
  • Night sweats
  • Sexual dysfunction
  • Headaches

The Connection Between Sleep Apnea & High Blood Pressure

You may not know this, but sleep apnea and high blood pressure have more in common than you think. These two conditions are dangerous on their own, but they can be a real nightmare together.

We all know how it feels to wake up after a restless night of sleep— you may feel groggy and unfocused, maybe you even have a headache. But what you may not realize is that your poor sleep quality or short sleep duration may also be affecting your heart health.

To better understand the connection between high blood pressure and OSA, let's begin by taking a look at some key points about hypertension and how it affects your body.

How Hypertension Affects Your Body

How Hypertension Affects Your BodyA normal, healthy blood pressure reading is around 120/80 or below— while it's normal for your blood pressure to fluctuate during the day, consistently elevated blood pressure is not normal and may indicate hypertension as well as additional complications.

High blood pressure contributes to hundreds of thousands of fatalities each year. Left untreated, hypertension can damage your heart and contribute to severe health issues that can lead to a disability or even premature death. Some of these include:

  • Cardiovascular Disease
  • Atrial Fibrillation
  • Aneurysms
  • Heart Attacks or Failure
  • Vision Loss
  • Stroke
  • Kidney Disease or Failure

Hypertension and Poor Sleep

There is a clear link between a person's sleep patterns and their risk for high blood pressure. A study by the Journal of Sleep Medicine found that people who get less than six hours of sleep each night were 20 percent more likely to have hypertension.

A study by the journal Hypertension showed that people who get less than six hours of sleep each night were shown to have higher blood pressure the next day, as compared to those who got the recommended amount of sleep the night before. This pattern, continued over time, only works to compound the issues and increase the risk for hypertension.

By getting appropriate sleep quality as well as quantity each night, it's possible to avoid this issue. However, doing this isn't so simple if you also have a sleep disorder.

As mentioned earlier, about half the people experiencing hypertension have obstructive sleep apnea as well. Hypertension doesn't cause sleep apnea, but there is a connection between the two.

Obstructive Sleep Apnea Can Cause High Blood Pressure

When you periodically stop breathing in your sleep, your body releases stress hormones. The American Heart Association explains, that with obstructive sleep apnea, these hormones can lead to high blood pressure, stroke, and heart disease.

Slowed or disrupted breathing causes blood oxygenation to decrease, which triggers the brain to send signals to increase blood pressure and heart rate in an attempt to increase oxygen supply to the body's tissues.

Even when awake, the effects of obstructive sleep apnea can cause your blood pressure to stay elevated.

Apnoeic periods, or moments when you stop breathing, that occur while you sleep can cause your blood pressure to remain high throughout the day. Sleep apnea can cause hypertension due to the drop in blood oxygenation during apnoeic periods. When this is a frequent occurrence, blood pressure continues to stay elevated even when adequate oxygenation is occurring.

In addition to the other health conditions that hypertension contributes to, high blood pressure can also make sleep apnea symptoms worse, and vice versa. These two conditions have a cyclical effect upon each other, which is concerning if you happen to have both.

Obstructive sleep apnea restricts your breathing by blocking your airways. The blocked airway restricts how much oxygen enters the body, which puts added stress on your cardiovascular system.

In what's known as blood pressure dipping, blood pressure can lower between 10 and 20 percent each night in healthy individuals. Those with obstructive sleep apnea experience dips of less than 10 percent, which puts them at a higher cardiovascular risk.

Sleep Apnea Forces The Heart to Work Harder

The airway blockages created by obstructive sleep apnea cause your blood pressure to increase, because your heart is working harder to get oxygenated blood flowing through your body. While you're asleep, sleep apnea triggers the brain to pump more blood to key areas like the brain and heart. This puts added pressure on your artery walls and spikes your blood pressure higher than if you were breathing normally while asleep.

Sleep Apnea Creates Norepinephrine Spikes in the Body

When your airway is blocked or constricted at night when you're asleep, your body must find a way to open up the airway so you can breathe. It does this by releasing norepinephrine, also sometimes referred to as adrenaline. Norepinephrine—norepinephrine— is the main "awake" neurotransmitter in the brain, and it arouses the brain to signal the throat to open up and let air in.

Although most people don't actually wake up, the arousal is enough to increase the muscle tone in the throat and return it to how it normally is during the day. Unfortunately, the norepinephrine release also creates a "fight or flight" response in your body that increases your heart rate, as well as your blood pressure.

Its release is so effective at raising blood pressure in the body that norepinephrine is used in the ICU to treat people in shock and at risk of death owing to low blood pressure. This is because it's the most powerful agent we know of to increase blood pressure.

The more frequently you have these respiratory events at night, the more norepinephrine you're going to release, and the more your blood pressure will rise. This can make keeping blood pressure under control exceedingly difficult if you have undiagnosed sleep apnea or aren't properly treated.

When someone with obstructive sleep apnea stops breathing during sleep, or their breathing is restricted and they struggle to breathe, resuming breathing will also spike the blood pressure. The cycle of stopping and resuming breathing can also cause a person to wake up during the night, which can spike your blood pressure even further.

Does Sleep Apnea Treatment Help High Blood Pressure?

Thankfully, yes! Research indicates that treating sleep apnea can lead to dramatic improvements for those suffering from hypertension. One of the most common and effective treatments for OSA patients, CPAP therapy— continuous positive airway pressure — not only improves sleep quality, but also improves blood pressure in those with hypertension. Studies have shown that CPAP therapy dramatically reduces high blood pressure in adults with obstructive sleep apnea.

 
 

How Does Sleep Apnea Treatment Affect Blood Pressure

CPAP treatment doesn't actually lower blood pressure levels, but it prevents the events that lead to blood pressure increasing at night. By removing the airway blockages that lead to arousals during the night, CPAP prevents the production of night time norepinephrine, and in the process stops blood pressure from rising to abnormal levels.

A tell-tale sign that severe OSA is making your hypertension worse is when many of the normal solutions for treating high blood pressure, such as getting more exercise and adhering to a healthier diet, don't work. In this case, especially if you snore during the night, which is a major sign of airway blockage, there's a strong likelihood that your hypertension won't improve unless your sleep apnea is treated. This is where seeing a doctor for your untreated OSA becomes especially important.

Your quantity and quality of sleep are directly related to your blood pressure levels, and it's important to get a good night's sleep every night if you wish to maintain healthy blood pressure. But if you find this to be much easier said than done, then it's important to seek additional treatment.

Next Steps to See if Sleep Apnea is Impacting your Blood Pressure

If you suffer from hypertension but aren't sure if sleep apnea or another sleep disorder is a contributing cause, getting an evaluation to rule it out is important. Reach out to your doctor or a sleep expert to set up a sleep study and to explore your treatment options. The solution could simply be a consultation away.

Sleep and high blood pressure have more in common than you may originally think— they affect each other to the point where seeking treatment for one condition may also end up treating another. Proper sleep and caring for your heart not only keeps you healthy, but they keep the two parameters healthy as well.

Treating Your Sleep Apnea Can Also Help Treat High Blood Pressure

As your breathing improves and your oxygen levels stabilize in response to treatment for sleep apnea, your blood pressure may also get better.

While you should always speak with your doctor before adjusting your medications, some people are able to reduce their intake of blood pressure medications after treatment for sleep apnea.

Breathing Exercises for Sleep Apnea

Some breathing exercises can help strengthen oral muscles:

Fake yell

  • First, open your mouth as wide as possible and stick your tongue out in a downward position. Your tongue needs to be as far out as possible. The uvula, the small fleshy piece in the back of your throat, needs to be lifted upwards as you stick your tongue out.
  • Secondly, use a mirror to ensure that you're raising the uvula correctly. After practice, you will be able to sense the uvula lifting, and you will not require the mirror. Hold the elevated uvula for five seconds and repeat 10 times.

Jaw Release

  • A tight jaw puts added pressure on your breathing passages. With your tongue in the resting position and your mouth closed, arch your tongue against the roof of your mouth and slide the tip of your tongue back as far as it will go along the roof of your mouth.
  • Additionally, repeat this process two times each day for five minutes to aid in reducing sleep apnea issues.

Myofunctional therapy for sleep apnea

Myofunctional therapy is one of the innovations to help sleep apnea patients outside of CPAP therapy. The method helps correct the improper function of the tongue and facial muscles. It also involves strengthening the tongue and orofacial muscles by teaching individuals how to engage the muscles in the appropriate position.

This type of sleep apnea treatment is especially helpful for patients with sleep apnea who happen to be mouth breathers. Mouth breathing exercises through the therapy can help reduce other issues such as neck and shoulder tension and speech problems related to mouth breathing. The techniques not only help reduce the instances of apneas at night but also improve breathing.

Think you may have sleep apnea?

You can start your journey towards more restful sleep, right away. Untreated sleep disorders can negatively affect your physical and emotional health. Sleep testing can help you get the answers you need to receive the treatment that you deserve.

Conclusion

OSA is highly prevalent with an estimated rate of 4.1-7.5% and 2.1-3.2%s in middle-aged men and women respectively. In recent years, there has been a large body of work assessing the role of OSA as an independent risk factor for hypertension. Certain patient characteristics & causes may confer an increased likelihood that hypertension is secondary to underlying sleep apnea.

Furthermore, early diagnosis and sleep apnea treatment may be beneficial in the management of hypertensive patients, particularly those with poorly controlled hypertension and high blood pressure.

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Dr. Sintayehu Abebe

Dr Sintayehu Abebe is a Consultant Internist and Interventional Cardiologist at the Addis Ababa University. The young and energetic Dr Abebe who is always keen on learning new things is also President of the Ethiopian Society of Cardiac Professionals (ESCP).

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