The heart and lungs work closely together to keep your body healthy and functioning. If you have heart disease, it’s natural to feel concerned about how it might affect your breathing and lungs. Understanding the connection between your heart and lungs is an important first step toward managing symptoms and improving your quality of life.
The heart is part of the circulatory system, not the respiratory system. The circulatory system includes the heart and blood vessels that transport blood throughout the body. The respiratory system includes organs such as:
The respiratory system brings oxygen into your body and removes carbon dioxide, a waste product produced during breathing.
The heart and the respiratory system work closely together. The heart pumps blood throughout your body, and the lungs add oxygen to this blood while removing carbon dioxide. Without the heart’s essential role in this process, your body wouldn’t get the oxygen it needs to function, and carbon dioxide would build up to dangerous levels.
The connection between the heart and respiratory system begins in the lungs. When you breathe in, oxygen fills tiny air sacs in your lungs called alveoli. From there, oxygen moves into the capillaries, the smallest blood vessels. At the same time, carbon dioxide, a waste product made by your body’s cells, moves from the capillaries into the alveoli, where it’s exhaled.
Next, the pulmonary veins carry the oxygen-rich blood to the heart’s left atrium. The blood then flows into the left ventricle, which pumps it through the aorta to the rest of the body. The oxygenated blood travels through your body, delivering oxygen to your organs and tissues while picking up carbon dioxide.
The right side of the heart receives the body’s oxygen-poor blood. The right atrium collects the blood and sends it to the right ventricle, which pumps it through the pulmonary artery back to the lungs. In the lungs, carbon dioxide is exchanged for fresh oxygen.
This constant cycle of pumping blood and exchanging gases keeps your body’s cells healthy and functional. When this process is disrupted by a condition like heart disease or lung disease, it can lead to serious health problems.
If you have heart disease, your heart may struggle to pump blood effectively, which can have an impact on your lungs and breathing. Heart conditions can affect your respiratory system in a number of ways.
A weakened heart muscle can’t pump blood as efficiently. This can cause blood to back up in the lungs, leading to pulmonary edema (fluid buildup). When fluid builds up in the lungs, it’s harder for oxygen to pass from the air sacs into the blood. This can cause shortness of breath and difficulty breathing, especially when you’re lying down or engaged in physical activity.
High blood pressure in the arteries that carry blood from the heart to the lungs is called pulmonary hypertension. The most common cause of pulmonary hypertension is weakness (failure) of the left ventricle, which leads to fluid buildup and increased pressure in pulmonary blood vessels. The right ventricle is forced to work harder, which can weaken it over time and cause right-sided heart failure, often leading to swelling (edema) in the legs. Pulmonary hypertension can also cause symptoms such as chest pain, dizziness, and shortness of breath.
Coronary artery disease occurs when the blood vessels that supply the heart muscle become narrowed or blocked, reducing blood flow to the heart. The heart doesn’t get enough oxygen-rich blood, which can lead to angina (chest pain) and shortness of breath. If the blood vessels become blocked, a heart attack can happen. This can result in permanent damage to part of the heart muscle, reducing the heart's ability to pump and causing long-term heart failure.
Some arrhythmias (abnormal heart rhythms) can disrupt the normal flow of blood through the heart and lungs. When the heart beats too fast, too slow, or irregularly, it reduces the amount of oxygenated blood circulating through the body, causing heart failure symptoms like lightheadedness, shortness of breath, and chest discomfort.
A heart attack occurs when a blockage in a coronary artery cuts off blood flow to part of the heart muscle. This damage can weaken the heart’s ability to pump blood, which may lead to breathing problems and fluid buildup in the lungs.
When the heart isn’t working properly, the respiratory system often tries to make up for it by ensuring your body gets enough oxygen.
Your body may try to get more oxygenated blood by speeding up your heart rate, which also increases your breathing rate. This can help raise oxygen levels in the blood, but it may also cause shortness of breath and fatigue. Over time, a rapid heart rate can weaken the heart.
When the brain and organs aren’t getting enough blood, the nervous system signals to your peripheral blood vessels to tighten and makes your heart beat faster. The nervous system also causes the arteries that feed vital organs, such as the brain, to widen, helping increase blood flow.
However, this compensation isn’t always enough. If the heart condition is severe, these adjustments may not fully make up for the heart’s inability to pump blood efficiently, leading to worsening symptoms.
Heart and lung diseases such as chronic obstructive pulmonary disease (COPD), pulmonary edema, and pulmonary hypertension often create a cycle in which each condition worsens the other.
COPD, which includes chronic bronchitis and emphysema, makes it hard for air to flow in and out of the lungs. The reduced amount of oxygen in the blood puts extra strain on the heart and, over time, can lead to pulmonary hypertension and eventually right-sided heart failure.
Pulmonary edema occurs when fluid builds up in the lungs due to heart failure, making it harder to breathe. This can cause anxiety and panic, raising heart rate and blood pressure, which puts more strain on the heart.
Pulmonary hypertension can make it harder for the right ventricle to pump blood into the lungs, leading to right-sided heart failure, which worsens breathing problems. As mentioned earlier, pulmonary hypertension can result from either heart or lung problems.
If you have heart disease, it’s important to understand how it might affect your lungs and breathing, as well as how your lifestyle can help. Your cardiologist is the person best suited to answer specific questions about your heart health and breathing. Here are some good questions to start the right conversation:
Your doctor can provide personalized advice and recommend treatments or lifestyle changes to manage your symptoms and improve your quality of life.
The heart and respiratory system are deeply connected, and understanding how they affect each other is essential for managing heart disease. By learning how your heart condition might cause breathing symptoms and by working closely with your health care provider, you can better manage your symptoms and maintain your overall health.
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