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

Your heart and lungs work together to move oxygen-rich blood throughout your body and refill it. Problems with these vital organs can spell trouble for your cardiovascular system and the rest of your body. People living with pulmonary hypertension or pulmonary arterial hypertension (PAH) usually an issue in their your lungs, 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 PH and 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 single 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 Your 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 and right artery that each carries blood to your left and right lungs.

From Your Lungs to the Left Side of Your Heart

Inside the lungs, carbon dioxide from your body is exchanged for oxygen. The blood is then moved into your pulmonary veins and your 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 powerful chamber responsible for pumping oxygenated blood to the rest of your body. It travels through the aortic valve and into the aorta — the largest artery in your body. From there, blood moves to your other organs, tissues, and cells.

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

What Factors Affect Your Lung and Heart Function?

Your lungs and heart are closely connected — if a problem arises with one organ, chances are that the others 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:

• Body weight
• Blood pressure levels
• Cholesterol levels
• Blood sugar levels
• Smoking status
• Exercise frequency

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

How Are the Lungs and Heart Affected by PH?

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

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

For example, PH is one of the causes of right-sided heart failure. Also known as cor pulmonale, right-sided heart failure occurs when your right ventricle becomes stretched and enlarged as it pumps blood through your narrowed pulmonary arteries.

Below are the five groups of PH and how the heart and lungs each play a role.

Group 1 PH

Group 1 PH is referred to as 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 — Up to 20 percent of PAH cases are heritable (passed down from one generation to the next)
• Drug-induced — Develops from taking diet pills, amphetamines, or certain drugs used to treat cancer
• Other diseases — Including liver disease, heart disease present at birth, and scleroderma (a disease that hardens and tightens the skin and can also affect internal organs)

Group 2 PH

Group 2 PH is caused by left-sided heart disease. This is the most common PH group in the United States. People with group 2 PH either have left-sided heart failure or left-sided heart valve disease. This means you have a problem with your mitral or aortic valves.

When the left side of your heart fails, it can’t properly pump blood out to the rest of your body. Blood backs up in your heart and lungs, increasing pressure in your pulmonary arteries. With heart valve disease, the mitral or aortic valves don’t close properly, leading to increased pressure in your heart and pulmonary arteries.

Group 3 PH

Hypoxia (low oxygen levels) or lung disease causes group 3 PH. People who are more likely to develop group 3 PH include those who live at high altitudes or have certain health conditions, including:

• Chronic obstructive pulmonary disease — Also called COPD, this long-term lung condition restricts airflow, making it difficult to breathe.
• Interstitial lung disease — This group of lung disorders causes scarring and inflammation of the lung tissue.
• Sleep apnea — In this sleep disorder, a person’s breathing repeatedly stops and starts during sleep.
• Pulmonary fibrosis — This lung disease is characterized by lung tissue scarring, causing breathing problems.

Group 4 PH

Chronic (long-term) blood clotting disorders in your lungs can also lead to PH. One condition known as chronic thromboembolic pulmonary hypertension (CTEPH) occurs when blood clots can’t dissolve in the lungs. These blood clots block blood flow and cause scar tissue buildup in the pulmonary arteries. As a result, the right side of the heart has to work harder to pump blood and may eventually fail.

Group 5 PH

Group 5 PH refers to PH that’s caused by other diseases, but doctors and researchers aren’t exactly sure why. Examples of diseases that lead to group 5 PH include blood disorders like sickle cell anemia and inflammatory diseases like sarcoidosis (causes inflammation and small lumps or granulomas to form in various parts of the body).

People living with PH need to understand the connection between the lungs and heart. These essential organs work together to keep the body healthy. This knowledge equips people with PH to make informed choices about their health, effectively manage their condition, and work closely with health care experts to improve their overall well-being.

Talk With Others Who Understand

On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 51,000 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 hypertension or pulmonary arterial hypertension? How do you manage it? Share your experience in the comments below, or start a conversation on your Activities page.