Sleep apnea doesn’t only affect your nights. It can also cause health issues during the day. One common health problem linked to obstructive sleep apnea (OSA) is high blood pressure.

If you or a loved one has OSA, understanding this connection can help you take steps to protect your health and know when to get more help. In this guide, we explain what high blood pressure is and how it’s linked to sleep apnea.

What Is High Blood Pressure?

Blood pressure is the force of blood pushing against the walls of your blood vessels. Your heart pumps blood throughout your body, and it needs steady pressure to keep everything moving. A normal blood pressure is less than 120/80 mm Hg (millimeters of mercury).

When pressure is too high for too long, it can cause damage to your heart, blood vessels, and other organs. High blood pressure, also called hypertension, is a common condition that affects almost half of adults in the United States. Because high blood pressure often has no symptoms, many people don’t even know they have it.

Symptoms of High Blood Pressure

Most of the time, hypertension is asymptomatic. This means that it doesn’t cause any noticeable symptoms. That’s why hypertension is sometimes called a silent condition. In severe cases, people with high blood pressure may have complications that cause:

• Headaches
• Blurry vision
• Dizziness
• Nosebleeds
• Shortness of breath

These symptoms can be caused by many other conditions, so having them doesn’t necessarily mean that you have high blood pressure. The only way to know for sure is through measuring your blood pressure, a quick and easy test.

Common Causes of High Blood Pressure

Many risk factors can raise your blood pressure, including:

• Older age
• Physical inactivity
• Eating too much salt
• Certain medical conditions
• Family history of hypertension
• Stress
• High body weight (overweight or obesity)
• Sleep problems, including untreated sleep apnea

Sleep apnea is a major risk factor for high blood pressure. Understanding how sleep apnea increases the risk of high blood pressure can help you protect your heart and promote a better quality of life.

How Sleep Apnea Affects Your Body at Night

OSA happens when the muscles in your throat relax during sleep and block your airway. This causes pauses in breathing, snoring, gasping or choking sounds, drops in oxygen, and waking up over and over.

These breathing interruptions can happen many times per hour. The constant stop-and-start pattern affects your heart, nervous system, and blood vessels.

Here’s what happens inside your body during a sleep apnea episode:

• Hypoxia (oxygen levels drop)
• The brain senses a problem and briefly wakes you to reopen the airway.
• Stress hormones surge to help restart breathing.
• Blood pressure rises as the heart beats faster and vessels tighten.

This cycle can happen many times during the night. Over time, this constant stress can cause blood pressure to stay high, even during the day.

How Does Sleep Apnea Cause High Blood Pressure?

There is strong scientific evidence that OSA can lead to long-term high blood pressure. Untreated sleep apnea sends your body into fight-or-flight mode again and again throughout the night.

Why This Matters

When stress hormones stay high over time, your blood vessels remain tight, even throughout the day. Tight, stiff blood vessels make your heart have to work harder. This leads to high blood pressure both at night and during the day.

People with moderate to severe sleep apnea have a much higher risk of developing high blood pressure compared with people who do not have sleep apnea. This doesn’t only affect adults with OSA. Children with sleep apnea have a higher risk of developing high blood pressure as young adults.

Nighttime High Blood Pressure

High blood pressure at night is especially concerning. In a healthy person, blood pressure naturally drops at night during sleep. This gives a chance for your heart to rest.

In people with sleep apnea, blood pressure may not drop at night, and may even get higher during sleep apnea episodes. These spikes can happen dozens or even hundreds of times. Nighttime high blood pressure can be a strong predictor of heart disease and stroke.

Daytime High Blood Pressure

Sleep apnea can also raise blood pressure during the daytime. After being woken up repeatedly throughout the night, your body stays in a stressed state. This keeps stress hormones high even when you’re awake.

Studies show that people with untreated sleep apnea are more likely to develop:

• High blood pressure throughout the day
• Hard-to-control hypertension
• High blood pressure that doesn’t improve with usual medications

In fact, sleep apnea is one of the most common underlying causes of treatment-resistant hypertension. Treating sleep apnea can make blood pressure medications work better.

How Treating Sleep Apnea Helps Lower Blood Pressure

The good news is that treating sleep apnea can help reduce blood pressure and reduce the risk of hypertension for many people.

Continuous Positive Airway Pressure Therapy

Continuous positive airway pressure (CPAP) is one of the most effective treatments for OSA. A CPAP machine keeps your airway open while you sleep by delivering gentle air pressure through a mask. Many studies show that using CPAP treatment regularly can:

• Lower nighttime and daytime blood pressure
• Reduce blood pressure spikes during apnea events

Some people may notice improvements in their blood pressure within a few weeks, especially if it was high because of sleep apnea.

Other Treatments

Not everyone with sleep apnea uses CPAP therapy. Other OSA treatments can improve sleep quality and overall health. But CPAP has the best evidence for lowering blood pressure in people with OSA. Other treatment options include:

• Lifestyle changes, such as weight management, side-sleeping, and treating nasal congestion
• Oral appliances
• Certain types of surgery
• Myofunctional therapy (measures that strengthen upper airway muscles)

When To Talk With Your Doctor

You should talk with your doctor if you have:

• Sleep apnea, and you’re concerned about high blood pressure
• High blood pressure readings at home
• Blood pressure that stays high even with medication

Tell your doctor if you think your sleep apnea is affecting your blood pressure. They may recommend a sleep study, treatment changes, blood pressure medications, or a heart-health check.

Join the Conversation

On MySleepApneaTeam, people share their experiences with obstructive sleep apnea, get advice, and find support from others who understand.

Do you have high blood pressure and sleep apnea? Let others know in the comments below.