Symptom: Shortness of Breath

Reviewed by: HU Medical Review Board | Last reviewed: November 2019

Shortness of breath, also called dyspnea, is a common symptom of heart failure (HF).1-3 It is normal for healthy individuals to experience shortness of breath when engaged in vigorous activity such as running, climbing flights of stairs, or other strenuous activities. However, breathlessness when walking, doing laundry, or climbing a few stairs doesn’t always mean you are out of shape; it could be a sign of heart failure or other medical problems.1,2,4,5

If you find your shortness of breath is happening more often or getting worse, it may be time to talk with your healthcare team. For example, waking up short of breath or experiencing discomfort while lying down could be signs of heart failure.6

Causes of dyspnea

The heart and lungs are part of the transport system which brings oxygen to the body tissues and removes sodium, carbon dioxide, and other waste products. If you have heart failure, the heart has to work harder to pump blood around your body and is no longer working as efficiently to bring oxygen-rich blood to your tissues.3,7 This decrease in oxygen in the blood can cause dyspnea.

Fluid accumulation in the lungs, also called pulmonary congestion or pulmonary edema, is a common symptom in heart failure. The congestion makes it more difficult for the lungs to replenish the blood with fresh oxygen. This impaired exchange causes dyspnea and worsens as heart failure advances.3,8


Dyspnea can be caused by a number of different conditions, diseases, medications, and levels of exertion.1,6 The symptoms associated with heart failure vary from person to person. For example, some people feel tired when they walk or they have to stop often to rest; others can’t catch their breath or feel discomfort or tightness in their chest.1,3

At first, you may not even notice a change in your breathing. Then you may feel shortness of breath upon exertion - during exercise or physical activity. But as HF progresses, you may also have difficulty breathing when resting or lying down (orthopnea).1,3,4,6,8 This is because the fluid in the lungs moves the way you do; with gravity.8 Blood naturally pools in the veins of the legs when you are upright. If you are lying flat, the blood remains in your circulating bloodstream. With heart failure, the heart may have difficulty managing the blood volume returning to the heart, so the excess fluid backs up inside the lungs and causes shortness of breath.3

If you find yourself waking up in the middle of the night or in the morning with difficulty breathing, coughing, or wheezing, this is called paroxysmal nocturnal dyspnea. Many people find they are more comfortable and can reduce these symptoms by sleeping on a stack of pillows or in a recliner which elevates their head and upper body.3,8 These symptoms often resolve after sitting up for a while.3

If breathlessness at night is a new symptom, call your healthcare team or discuss it at your next appointment so that they are aware of the changes in your condition.

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