Shortness of Breath

Reviewed by: HU Medical Review Board | Last Reviewed: May 2016. | Last updated: June 2021

Shortness of breath is defined as a “subjective experience of breathing discomfort.”1 Along with cough, wheeze, and chest tightness, it is a typical symptom of asthma.

In an international survey, children with asthma were asked about early signs that their asthma was worsening.2 Breathlessness was the most common answer. More than 40% of children said it was the first sign that their asthma was getting worse.

One study showed that 100% of adults seen in the emergency room for acute asthma reported breathlessness.3

What causes shortness of breath?

In asthma, shortness of breath is usually caused by the narrowing of the airways. The airways become narrow for one or both reasons:

  • The muscles that surround the airways tighten up (“bronchospasm”).
  • Inflammation makes the airways swell and fill with mucus.

The medical term for shortness of breath is dyspnea. People describe it as air hunger, fast breathing, running out of air, or not being able to breath fast or deep enough.1,4 Similar to thirst, hunger, or pain, it is nearly impossible to ignore.4 Because it is a subjective symptom, you can feel and describe it, but a health care provider cannot observe or measure it.

When is it abnormal?

Some breathlessness is normal, such as after hard exercising or when you have a stuffy nose. However, it is a problem when it is greater than expected for a given level of physical effort.1

If shortness of breath continues for more than a month, it is considered chronic.1 Shortness of breath also can come on suddenly. Breathlessness is a symptom of many different conditions, so your medical history and a physical examination will provide important clues to the cause. For about two-thirds of patients, the signs and symptoms are enough to make an accurate diagnosis.1 Occasionally, additional tests may be needed.

What other conditions can cause shortness of breath?

In adults, asthma, congestive heart failure, heart attack, chronic obstructive pulmonary disease (COPD), scarring of the lung tissue, and anxiety cause 85% of shortness of breath cases.1 More than one-third of people have two or more causes of breathlessness.1 The occurrence of breathlessness is highest in people who are 55 to 69 years old.5

In children, the most common causes of breathlessness are asthma, infections, and upper airway blockage.4

How is shortness of breath evaluated?

If shortness of breath starts suddenly, it can be a sign of a medical emergency. Warning signs in children are breathlessness with sore throat, croupy cough, or listlessness/lack of energy.4 Warning signs in adults are shortness of breath while at rest and if accompanied by chest pain.4

If you have chronic shortness of breath, your provider may ask questions such as:1

  • When did you first feel short of breath?
  • How long has it been going on?
  • How would you describe it?
  • How severe is the feeling of breathlessness?
  • Is it more difficult to get air in or out?
  • Do you feel this way all the time, or does it come and go?
  • What other symptoms have you noticed?

Breathlessness that comes and goes is a sign of asthma.5 Shortness of breath caused by allergies or other common asthma triggers is another sign of asthma. Finally, breathlessness with wheezing indicates asthma.5


If the history and physical exam suggest that you have asthma, your provider may asked you to do spirometry.5 Spirometry is an important lung function test to evaluate how much and how quickly you can exhale air. The test is usually done before and after taking a medication that opens the airways (“bronchodilator”).5 Asthma is likely if medications are able to open the airways.

How is asthma-related shortness of breath treated?

If shortness of breath is due to intermittent asthma, your provider may prescribe a rescue inhaler for use as needed. Asthma is considered intermittent if symptoms occur less than three days per week, do not limit activities, and rarely wake you up at night.6

If shortness of breath and other symptoms occur more frequently, your provider may recommend starting long-term treatment for asthma. Initial treatment of persistent asthma usually involves inhaled corticosteroids and avoiding asthma triggers.6

For some people asthma, breathlessness and being out of shape become a vicious cycle.7 Exercise is a common trigger for asthma symptoms. These symptoms can be uncomfortable, which discourages people from exercising. Unfortunately, getting out of shape makes you feel even more short of breath when you are active. Your provider can work with you to find the right combination of medications that allows you to be active. Your provider or respiratory therapist can work with you to make an exercise plan.

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