What Is The Connection Between Sleep Apnea and High Blood Pressure?

Medically reviewed by
 Dr. Nayantara Santhi

Dr. Nayantara Santhi

Dr. Nayantara Santhi holds an academic position at Northumbria University. After completing her Ph.D. at Northeastern University (Boston, MA), she joined the Division of Sleep Medicine at Harvard Medical School as a post-doctoral fellow to research how sleep and circadian rhythmicity influence our cognitive functioning.

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Last Updated On January 17th, 2024
What Is The Connection Between Sleep Apnea and High Blood Pressure?

Key Takeaways

  • Link Between Blood Pressure and OSA: There is a strong link between high blood pressure (hypertension) and obstructive sleep apnea (OSA). OSA, a sleep disorder characterized by repeated interruptions in breathing during sleep, significantly increases the risk of developing hypertension.
  • Effects of OSA and High Blood Pressure: The relationship between the two conditions is cyclical, as untreated OSA can lead to high blood pressure, and high blood pressure can worsen OSA. It’s crucial to address both conditions to prevent potential health complications.
  • Treating with CPAP Therapy: Continuous Positive Airway Pressure (CPAP) therapy, a common treatment for OSA, has been shown to reduce high blood pressure. Managing sleep apnea through CPAP therapy can help prevent nighttime spikes in blood pressure and improve overall cardiovascular health.

At face value, high blood pressure and sleep apnea may seem like they’re worlds apart. Obstructive sleep apnea syndrome can make high blood pressure worse or even cause it, highlighting the important link between these two conditions. However, when we dig a little deeper, it may surprise some to learn that research repeatedly suggests a link between the two, though more research is still needed. 

Independently, both conditions are pretty serious. But when they run concurrently, as they often do (which you’ll see here shortly), it can be a recipe for disaster.

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In this article, we’ll take a look at high blood pressure and obstructive sleep apnea; we’ll also examine how the two are related.

What is High Blood Pressure?

Essentially, blood pressure is the force of your blood pushing against the walls of your arteries. Blood pressure is measured using two numbers; the first number is called systolic blood pressure, which measures the pressure in your arteries with each heartbeat. The second number is called diastolic blood pressure, which measures the pressure in your arteries between Heartbeats or when your heart is at rest. A normal BP is 120/80. Verified Source Centers for Disease Control and Prevention (CDC) The United States’ health protection agency that defends against dangers to health and safety. View source

Also known as hypertension, Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source high blood pressure is just as it sounds blood pressure that is higher than normal. In other words, if your blood pressure is high, Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source your blood is likely pushing against your artery walls more forcefully.

Everyone’s blood pressure rises and falls throughout the day, and the reasons for these fluctuations are different for everyone. Normal changes in blood pressure can be caused by:

  • A change in temperature
  • Stress
  • Vigorous exercise
  • Foods that are high in sodium
  • Caffeine
  • A full bladder
  • Sleep

Again, all of the above are normal day-to-day things that cause our blood pressure to spike or drop. For most people, spikes in blood pressure often return to normal within a reasonable time frame. However, when someone is categorized as hypertensive, their blood pressure is consistently elevated with readings above the normal 120/80 threshold.

Dipping vs. Non-Dipping Hypertension

When you sleep at night, your blood pressure will drop anywhere from 10 to 20%; this is known as ‘nocturnal dipping’. However, for some people, their blood pressure only drops by less than 10% while they sleep; this is known as non-dipping blood pressure is quite common in people with severe obstructive sleep apnea.

How Are Sleep Apnea & High Blood Pressure Related?

There are two types of sleep apnea, obstructive and central sleep apnea.

Obstructive sleep apnea is where the throat muscles relax during sleep, causing the apnea (or temporary cessation in breathing). It is not uncommon for those who suffer from sleep apnea to stop breathing hundreds of times per night. If left unchecked, sleep apnea can lead to stroke, diabetes, heart failure, and hypertension (which we will see here shortly).

Central sleep apnea is usually the result of your brain sending the wrong signals to the muscles that control your breathing. This implies that your heart and blood vessels are exerting more effort than necessary. Snoring is a noticeable indicator of OSA, and this sleep disorder is strongly linked to cardiovascular diseases, diabetes, and stroke.

Obstructive sleep apnea is the more common of the two, and while research shows that OSA increases the risk for high blood pressure, the link doesn’t stop there. It would seem that the connection between the two is cyclical. About 50% of patients Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source with obstructive sleep apnea have high blood pressure, and as much as 40% of patients with high blood pressure have obstructive sleep apnea.

One multi-center polysomnography study Verified Source Johns Hopkins Medicine University focused on medical research that produces thoroughly reviewed health articles. View source (which included researchers from the Johns Hopkins School of Public Health) found that those who suffer from moderate to severe sleep apnea were more than twice as likely to have high blood pressure.

Moreover, severe obstructive sleep apnea has also been linked to drug-resistant hypertension. A 2014 study Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source published in the Journal of Clinical Sleep Medicine linked untreated severe obstructive sleep apnea with high blood pressure. This study found that participants with severe OSA had a higher likelihood of high blood pressure despite being on three or more blood pressure medicines. Additionally, researchers found a high prevalence of underlying sleep apnea in patients with resistant hypertension.

A sleep-related breathing disorder may lead to various health issues, including daytime sleepiness, fatigue, cognitive impairment, and an increased risk of cardiovascular problems such as hypertension and heart disease.

The two are linked such that high blood pressure may often be the first clue that someone has obstructive sleep apnea Verified Source Harvard Health Blog run by Harvard Medical School offering in-depth guides to better health and articles on medical breakthroughs. View source

How Does Sleep Apnea Cause High Blood Pressure?

Obstructive sleep apnea episodes have been shown to cause a spike in both systolic and diastolic pressure. Researchers have found that not only do the patient’s average blood pressure levels remain elevated at night, but many OSA patients tend to have elevated blood pressure levels Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source during their daytime or waking hours as well.

To fully understand how sleep apnea causes high blood pressure, you’ll need to consider how the sympathetic nervous system works.

The sympathetic nervous system kicks into gear for actions that require quick responses. Its primary function is to activate your body’s fight-or-flight response. In stressful situations, the sympathetic nervous system will:

  • Boost your heart rate
  • Dilate your pupils
  • Activate your sweat glands
  • Increases your alertness
  • Regulate arterial pressure

What does this have to do with sleep apnea? Well, when you stop breathing as a result of sleep apnea, your body must find a way to breathe again. So, it releases the stress hormone adrenaline.

Sleep deprivation places strain on the heart, and obstructive sleep apnea (OSA) exacerbates this cardiovascular burden, highlighting the interconnected impact of these conditions on heart health. 

The relationship between the autonomic nervous system and sleep apnea involves disruptions in the normal functioning of this system during sleep, impacting factors such as heart rate, blood pressure, and overall physiological balance.

The presence of sleep apnea also raises the likelihood of developing insulin resistance and type 2 diabetes. Additionally, it is associated with metabolic syndrome, a condition characterized by high blood pressure, abnormal cholesterol levels, elevated blood sugar, and an increased waist circumference, contributing to an elevated risk of heart disease. 

While adrenalin is quite effective at signaling the brain to open your throat to let air in, it also activates your sympathetic nervous system and triggers your flight or fight response leading to an increase in your heart rate and a bump in your blood pressure.

Why is High Blood Pressure Such a Cause for Concern?

While it’s normal for your blood pressure to fluctuate, it’s not normal for it to be perpetually raised. High blood pressure forces your heart to work harder, and over time it can lead to more serious health concerns. If left untreated, high blood pressure lead to:

  • Heart disease Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source
  • Heart failure Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source
  • Stroke Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source
  • Kidney failure Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source
  •  Damaged and narrowed arteries
  •  Cognitive impairment
  •  Vision loss

Beyond these pretty serious health issues, high blood pressure is responsible Verified Source Centers for Disease Control and Prevention (CDC) The United States’ health protection agency that defends against dangers to health and safety. View source for approximately ½ million deaths in the U.S. each year.

OSA risk factors include obesity, a family history of sleep apnea, being male, older age, having a large neck circumference, and certain medical conditions like hypothyroidism or acromegaly. 

OSA may also heighten the risk of experiencing recurrent heart attacks, strokes, and irregular heartbeats, including atrial fibrillation. For individuals with heart disease, repeated episodes of low blood oxygen (hypoxia or hypoxemia) can potentially result in sudden death due to an irregular heartbeat.

Elevated blood pressure or heart issues can result from sudden drops in blood oxygen levels during OSA, placing strain on the cardiovascular system. The presence of OSA raises the risk of high blood pressure, also referred to as hypertension.

Do Treatments for Sleep Apnea Help High Blood Pressure?

If you suffer from sleep apnea and high blood pressure, there’s good news. Some studies Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source have shown that CPAP therapy has led to reduced hypertension in patients with OSA. To achieve blood pressure control, it’s important to focus on weight loss. 

A systematic review and meta-analysis of randomized controlled trials involves combining and analyzing data from multiple trials to draw comprehensive conclusions about the effectiveness or outcomes of a particular intervention or treatment in OSA. Moreover, CPAP therapy has also been shown to have a beneficial effect on daytime blood pressure. Verified Source National Library of Medicine (NIH) World’s largest medical library, making biomedical data and information more accessible. View source

When to See a Doctor

Another interesting thing about hypertension and sleep apnea is that both conditions are hard to identify by the patients themselves.  Hypertensive patients usually don’t have any outward symptoms, and many only learn of their condition courtesy of a routine exam at their doctor’s office.  Incidentally, it’s for this reason that high blood pressure is often called “the silent disease.”

Similarly, most people with obstructive sleep apnea are unaware of the condition. More often than not, it only comes to light when their partner complains about their loud snoring or gasping for breath. See our guide to signs you have sleep apnea.

Internal medicine plays a crucial role in the diagnosis and management of obstructive sleep apnea (OSA), addressing the impact of this sleep disorder on overall adult health through comprehensive evaluation and targeted interventions.

Routine visits with your primary care provider are your best bet for maintaining your vigilance for high blood pressure.

For sleep apnea, you’d probably want to see your doctor based on the repeated complaints of your partner or excessive daytime sleeping. However, if you manage to make it through those complaints of snoring, it’s more likely that nights of interrupted and restless sleep and daytime fatigue might be the impetus you need.

Implementing lifestyle adjustments, especially if you have a family history of high blood pressure, can prove highly effective when you are maintaining a healthy diet, achieving and sustaining a moderate weight, regular exercise, and ceasing smoking. 

The occurrence of left ventricular hypertrophy in individuals with and without obstructive sleep apnea is being examined. Additionally, surgeries for sleep apnea, like tonsil removal, may aid in removing obstructions linked to sleep apnea.

Consult with a doctor to determine if sleep apnea surgery is a safe and viable choice for your specific situation to help you manage sleep apnea and hypertension. Oftentimes, these are a last resort measure when other treatments have failed to ease symptoms.

Frequently Asked Questions

Can sleep apnea cause high blood pressure?

Yes, obstructive sleep apnea is a well-recognized risk factor for high blood pressure or hypertension. However, this largely applies to untreated OSA, which is why it’s so important to speak with a doctor and discuss diagnosis and treatment if you suspect you have sleep apnea. Treating sleep apnea can reduce its effects on blood pressure.

Does treating sleep apnea lower blood pressure?

Yes, CPAP treatment for sleep apnea has been linked to reduced blood pressure. In other words, treating sleep apnea can reverse its effects on blood pressure. Increased arterial stiffness is linked to acute sleep deprivation in healthy young adults.

However, your doctor may still recommend additional treatments for hypertension, such as medication and lifetsyle changes to help improve overall health and sleep quality.

Why does my blood pressure spike at night?

Sleep apnea isn’t the only condition linked to nocturnal hypertension. For example, nocturia, a condition where individuals need to regularly get up in the night to urinate, has been observed in greater numbers of people with hypertension than people without it, though nocturia may be a symptom of hypertension than the reverse.

Other conditions linked to nocturnal hypertension are shift work sleep disorder, diabetes, kidney disease, and restless leg syndrome.

What health issues can sleep apnea cause?

Aside from high blood pressure, sleep apnea is also linked to weight and obesity. This can become a vicious cycle, as the sleep loss from sleep apnea can make it more tempting for individuals to follow a poor diet that leads to weight gain, and this weight gain can worsen sleep apnea symptoms.

Untreated sleep apnea is also linked to insulin resistance and type 2 diabetes.

Can high blood pressure make it difficult to sleep?

Yes, just as sleep apnea and poor sleep is linked to high blood pressure, high blood pressure can make it difficult to fall asleep Verified Source Harvard Health Blog run by Harvard Medical School offering in-depth guides to better health and articles on medical breakthroughs. View source fast. The headaches, chest pain, and breathing troubles that comes with high blood pressure can cause discomfort and make it challenging to relax enough to fall asleep.

Continuous awakenings throughout the night due to obstructive sleep apnea (OSA) lead to partial sleep deprivation, and snoring, and result in daytime sleepiness. Sleepers should therefore try to do what they can to minimize the effects of HBP symptoms. For example, elevating the head of the bed can make breathing easier, eliminating any shortness of breath from lying down.

Conclusion

High blood pressure and sleep apnea are two distinct medical conditions, but evolving research continues to show that the two are intrinsically linked. So much so that obstructive sleep apnea is formally recognized as a secondary cause of high blood pressure. Research has found that sleep apnea is a huge risk factor for high blood pressure, and high blood pressure can worsen sleep apnea.

The two have a cyclic effect on each other, and there could be grave consequences for those who suffer from both.

But rest assured, the news is not all gloom and doom. CPAP machines are often recognized as the gold standard for treating sleep apnea, has also been shown to be an effective treatment for high blood pressure. By managing sleep apnea, CPAP therapy can prevent episodes of nighttime hypertension.


About the author

Eric Ridenour is a health and wellness writer with a strong focus on sleep and nutrition. With a background in health science and psychology, Eric has a deep understanding of the connection between sleep and overall well-being. His expertise has been sought by various businesses and individuals, and his work has been featured in reputable publications such as Thrive Global, Drug Report, and Authority Magazine. Eric's commitment to promoting better sleep and comprehensive wellness is evident in his writing and consultations. He is a published author working on his second book.

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