An Overview of Shortness of Breath

Symptoms, Causes, Diagnosis, and Treatment

a woman having trouble breathing

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Shortness of breath is a common symptom that prompts people to make a visit to their doctor. This symptom may come on rapidly or come on so slowly that it's not recognized at first. If you are experiencing shortness of breath, that does not mean you should necessarily be worried about lung cancer or serious conditions such as heart disease.

There are many causes of shortness of breath. Yet, since "less common" causes of shortness of breath are often overlooked, it is important to make an appointment with your doctor to determine the cause.


We don’t have a clear definition of shortness of breath, but most people describe this symptom as a subjective sensation of difficulty with breathing. You may have a feeling of being unable to get enough air in or that it takes more effort than usual to breathe. Some people also describe a sensation of chest tightness.

Shortness of breath can come on acutely in a matter of minutes or hours; or chronically over days, weeks, months or even years. 

When to Seek Immediate Attention

If your shortness of breath is severe, came on suddenly, or is associated with symptoms of chest pain, coughing up blood, lightheadedness, pain, swelling, or redness of your lower legs, or if you feel like something could be seriously wrong (have a feeling of impending doom), call 911.

Some of the causes of shortness of breath can be life-threatening and need immediate medical attention. If you aren't certain you need emergent care, err on the side of caution.

Medical Terms

If you're reading about shortness of breath, you may be confused by all of the terms used to describe this symptom. A quick rundown of some of these terms include:

  • Dyspnea refers to the sensation of shortness of breath
  • Tachypnea refers to rapid breathing with or without a feeling of being shortness of breath
  • Bradypnea means a slow rate of breathing

A normal respiratory rate in adults is considered to be between 12 and 18 breaths per minute while at rest for adults and varies with children depending on age.

Respiratory rate is considered by some to be the "forgotten" vital sign, and can sometimes give your doctor more information than either your blood pressure or your pulse with regard to the severity of illness.

It's important to note that you may feel short of breath with a normal respiratory rate, or instead, could have an abnormal respiratory rate but not notice any difficulty breathing.


In 85 percent of people, conditions related to the heart and lungs are responsible for shortness of breath. Though most of us think of our lungs first if we feel short of breath, heart conditions need to be carefully considered.

A study that looked at people who had shortness of breath as their only symptom of heart disease had a greater chance of dying than those who had typical chest pain.

Some of the more common causes include:

  • Asthma
  • COPD
  • Heart attacks
  • Pulmonary embolism, a blood clot that breaks off from another blood clot (deep vein thrombosis) in the legs or pelvis and travels to the lungs
  • Infections such as bronchitis and pneumonia
  • Congestive heart failure
  • Pneumothorax, a collapse of a lung

Other common causes include:

  • Smoking
  • Anemia: With anemia, you may also note fatigue, pale skin, and lightheadedness
  • Thyroid conditions: Both hyperthyroidism and hypothyroidism may cause breathlessness

Less common but important causes of shortness of breath may include:

  • Benign and malignant tumors, including lung cancer: In the past, a persistent cough or coughing up blood were the most common symptoms of lung cancer. The most common cause of lung cancer at this time, lung adenocarcinoma, often causes shortness of breath as the first sign. Keep in mind that the majority of people diagnosed with lung cancer today are non-smokers (they either never smoked or quit sometime in the past).
  • Anxiety and panic attacks (learn more about the shortness of breath and chest pain related to panic attacks)
  • Objects inhaled accidentally into the lungs
  • Heart valve problems
  • Acid reflux
  • Allergic reactions (anaphylaxis)
  • Neurological diseases such as multiple sclerosis
  • Other lung diseases such as sarcoidosis and bronchiectasis
  • Lack of regular exercise: Before dismissing shortness of breath as being due to inactivity, talk to your doctor.


It’s important to make an appointment to see your doctor if you develop shortness of breath, even if you think there is a clear reason to explain your symptoms.

Contact your doctor or call 911 immediately if you have chest pain, feel lightheaded or if your symptoms worsen rapidly.

When you visit your doctor, she will take a careful history and do a physical exam. Some of the questions she may ask include:

  • When did you first experience shortness of breath and how did it first begin?
  • Do your symptoms occur at rest or only with activity? If you only feel short of breath with activity, which activities seem to cause your symptoms?
  • Do you feel more winded when you are sitting up or lying down?
  • Do you have any other symptoms, such as chest pain, a cough, wheezing, fever, leg pain, unexplained weight loss or fatigue?
  • Do you have a personal or family history of any heart or lung problems?
  • Have you ever smoked? If so, for how long?
  • Have you traveled recently by car or by plane?


The tests your doctor will recommend will depend on your particular symptoms and physical findings, but may commonly include:

  • Pulse oximetry, a test performed by putting a clamp on your finger or earlobe to estimate the amount of oxygen in your blood
  • An electrocardiogram (EKG) to look for signs of a heart attack or irregular heart rhythms
  • A chest x-ray to look for infections or growths in your lungs (keep in mind that plain chest x-rays can miss lung cancer in the early stages)
  • Blood work to look for anemia and other causes
  • Pulmonary function tests to look for asthma or emphysema and other lung conditions

Other tests may include:

  • A CT scan of your chest
  • A stress test
  • An echocardiogram. This is an ultrasound of your heart to look for problems with your heart valves, how strong your heart is and if you have any damaged areas in your heart.
  • A bronchoscopy. A bronchoscopy is a flexible tube that is placed through your mouth and down into your bronchi to look for tumors or a foreign body.

Dyspnea and COPD: For those who have COPD, dyspnea is very common and the degree of dyspnea you have can give a lot of information as to the severity of your illness or an exacerbation. To do this, doctors often use what is called the modified medical research council dyspnea scale.


The treatment of your shortness of breath will depend on the cause, but the most important first step is to make sure you are getting enough air to supply your tissues with the oxygen they need. In emergency medicine, this is referred to as the ABC's with A standing for airway, B standing for breathing, and C representing circulation.

When It Is an Emergency

Sometimes it can be hard to know how serious your shortness of breath is, and that's when it's important to go with your intuition. In fact, sometimes the most severe shortness of breath can be something benign, like hyperventilation or a panic attack, but the mildest symptoms could be related to very serious causes.

If you are questioning calling 911 at all, go ahead and do so. If you didn't need the help, that's okay. But if you do, you don't want to wait too long.

Call 9-1-1 For These Symptoms

Symptoms that suggest shortness of breath may be serious, however, include:

  • chest pain
  • a bluish tinge to your fingers and lips (cyanosis)
  • swelling or a feeling of fullness in your throat and lips
  • inability to talk due to difficulty breathing
  • a rapid increase in your symptoms

Don't try to drive yourself to urgent care or an emergency room, and it's better to call 911 than have a friend drive you. Finally, don't be fooled if your symptoms seem to be suddenly improving. A decreased level of consciousness or the movement of a foreign body lodged in an airway can make symptoms appear to improve transiently.

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