Members of myPHteam have asked others how their pulmonary arterial hypertension (PAH) relates to their hearts and lungs. “What does PAH mean or do to your heart? The shortness of breath is very scary,” one member posted.

Your heart and lungs work together to keep oxygen-rich blood moving throughout your body. A problem with either of these vital organs can spell trouble for your cardiovascular system and the rest of your body. When you’re living with PAH, one of five types of pulmonary hypertension (PH), there’s usually an issue in your lungs or heart — or both.

This article provides a general overview of how your heart and lungs function together. To understand one system, you’ll need to understand the other. Armed with this knowledge, you’ll have a better idea of what’s happening in your body with PAH.

How Do Your Heart and Lungs Work Together?

Your lungs and heart are interconnected systems that rely on one another to do their jobs. Blood is constantly moving in and out of these organs to supply your body with the oxygen and nutrients it needs. According to Cleveland Clinic, your heart and lungs circulate about 2,000 gallons of blood every day.

To best understand how your heart and lungs work together, we’ll follow your blood on a journey through your heart and lungs (the pulmonary circuit). It’s different from your systemic circulation, which moves oxygenated blood from your heart throughout your body to your other organs.

From Your Body to the Right Side of the Heart

Your pulmonary circuit begins in your right atrium. This top-right chamber of your heart takes in the oxygen-poor blood through two major veins — the superior vena cava and the inferior vena cava. The blood travels through your right atrium and passes through the tricuspid valve. These tissue flaps open and close to keep blood flowing in the correct direction through your heart.

The tricuspid valve controls blood from your right atrium into your right ventricle. This lower chamber then pushes blood through the pulmonary valve and into your pulmonary arteries. They’re the only arteries in your body that carry oxygen-poor blood. They branch off into a left artery and a right artery that carry blood to your left lung and right lung.

From Your Lungs to the Left Side of the Heart

Inside the lungs, carbon dioxide from your body is exchanged for oxygen. The blood is then moved into your pulmonary veins and left atrium. This chamber pumps blood through the mitral valve and into your left ventricle. This is your blood’s last stop in the journey through your lungs and heart.

The left ventricle is a chamber that’s responsible for pumping oxygenated blood to the rest of your body. Blood travels through the aortic valve and into the aorta — the largest artery in your body — and then flows to your other organs, tissues, and cells.

Once its oxygen and nutrients are used, the blood travels back through your circulatory system toward your heart, reaching the superior and inferior vena cava. The cycle then starts over again. Your heart is a powerful muscle that works fast — it takes less than a minute for blood to travel to a body part and return to the heart.

What Factors Have an Impact on Lung and Heart Function?

Your lungs and heart are closely connected — if a problem arises with one organ, chances are that the other will be affected. Studies show that your lung function is related to your heart health. For example, cardiovascular factors that play a role in lung health include:

• Blood pressure levels
• Cholesterol levels
• Blood glucose (blood sugar) levels
• Smoking status
• Exercise frequency

You can take extra steps to take care of your lungs and heart, especially while living with PAH. Your doctor will likely encourage you to eat a healthy diet, try to limit stress, quit smoking, and exercise regularly.

How Does Pulmonary Arterial Hypertension Affect the Lungs and Heart?

Now that you know how the lungs and heart work together, it’s easier to understand how PAH can affect them. PAH is a type of PH, which occurs when you have high blood pressure levels in your pulmonary arteries, leading to stiffness and narrowing. Again, these blood vessels move deoxygenated (oxygen-poor) blood from your heart to your lungs.

You may have high blood pressure in your pulmonary arteries for several reasons. The World Health Organization (WHO) classifies PH into five distinct groups based on the specific cause. Some types of pulmonary hypertension are caused by heart issues. Others are due to lung diseases that eventually also affect the heart.

Group 1 PH refers to pulmonary arterial hypertension. This condition makes your pulmonary arteries stiff, thick, and narrow. The right side of your heart has to work harder to pump blood to your lungs. Eventually, PAH can lead to right-sided heart failure.

More than half of PAH cases are idiopathic, meaning they have no known cause. Other causes of PAH include:

• Genetics — About 15 percent to 20 percent of PAH cases are heritable (passed down from one generation to the next).
• Use of certain drugs — PH can develop from taking diet pills, amphetamines, or certain cancer medications.
• Other diseases — Conditions linked with PAH include liver disease, heart disease present at birth, and scleroderma (a disease that hardens and tightens the skin and can also affect internal organs).

Although PAH is a progressive disease, meaning it gets worse over time, PAH medications can help.

How Do PAH Medications Affect the Lungs and Heart?

The goal of PAH medications is to slow disease progression and improve PAH symptoms. Just as PAH can affect the lungs and heart, PAH medications can affect these vital organs, too.

There are several types of PAH medications, and they work in different ways.

Activin Signaling Inhibitors

Activin signaling inhibitors are a newer type of drug for treating PAH. The first drug in this class has been found to help improve PAH symptoms, and it potentially helps slow disease progression by stopping the chain of events leading to increased pressure on the heart.

Anticoagulants

Anticoagulants can help prevent blood clots, which may contribute to disease progression in PAH.

Diuretics

Also known as water pills, diuretics help widen the blood vessels, making it easier for the kidneys to eliminate excess fluid and salt. For people with PAH, diuretics can help reduce swelling.

Oxygen Therapy

You may experience hypoxia (low oxygen levels) with PAH. Oxygen therapy can increase oxygen levels in the blood and reduce blood pressure by widening the blood vessels. Some people with PAH need oxygen all the time, whereas others require it only during physical activity, while on an airplane, or when at high altitudes.

Pulmonary Vasodilators

Pulmonary vasodilators can help improve blood flow by opening narrowed blood vessels. This can reduce the pressure on the heart and help ease PAH symptoms.

Calcium Channel Blockers

Calcium channel blockers change the way the body uses calcium. By relaxing the blood vessel walls to encourage more blood flow, these drugs can help lower blood pressure in the pulmonary arteries, prevent heart rhythm issues, and more.

Phosphodiesterase 5 Inhibitors

Phosphodiesterase 5 inhibitors relax blood vessels, which can help increase blood flow through the lungs and lower blood pressure.

Prostacyclin

People with PAH may be low in prostacyclin, a hormone released by the lungs that affects how blood vessels dilate. Taking a synthetic version of this hormone can help blood vessels relax, lowering blood pressure and reducing strain on the heart muscle.

Endothelin Receptor Antagonists

Endothelin receptor antagonists work by widening blood vessels, which can help decrease blood pressure in the lungs.

Soluble Guanylate Cyclase Stimulators

Soluble guanylate cyclase stimulators can help lower the pressure in the lungs by relaxing the pulmonary arteries.

These are just some of the types of PAH medications your doctor might recommend. According to the Pulmonary Hypertension Association, new PAH treatments continue to improve outcomes and quality of life. Ask your health care provider which PAH treatments they recommend and why. They may monitor you with blood tests, chest X-rays, an echocardiogram, and other diagnostic tests and tools. They’ll likely factor in your risk factors, family history, health history, and other medical conditions and may recommend lifestyle changes, like eating less salt and getting regular physical activity.

If your PAH progresses, your health care provider may recommend new or different treatment options. Don’t hesitate to ask your doctor any questions you have regarding their recommendations or the potential side effects of PAH medications.

The lungs and heart work together to keep the body healthy. Knowing how PAH and PAH medications affect these essential organs can help you make informed decisions about your health. It can also help you manage your PAH symptoms and work with health care experts to improve your quality of life.

Talk With Others Who Understand

On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 55,000 members come together to ask questions, give advice, and share their stories with others who understand life with pulmonary hypertension.

Have you been diagnosed with pulmonary arterial hypertension? What steps do you take to protect your heart and lungs? Share your experience in the comments below, or start a conversation on your Activities page.