Shortness of breath, also called breathlessness or dyspnea, is the feeling that breathing is difficult, uncomfortable or that you cannot get enough air. It may start suddenly or develop gradually. Because breathlessness can have many causes, new, severe or worsening symptoms should be medically assessed.
Common causes
Shortness of breath can be caused by conditions affecting the lungs, heart, blood, muscles or nervous system. Possible causes include:
- Asthma
- COPD and emphysema
- respiratory infections such as pneumonia or acute bronchitis
- heart disease or heart failure
- anemia
- anxiety or panic
- reduced physical fitness or obesity
Sudden breathlessness can also occur with serious emergencies such as a pulmonary embolism, heart attack, collapsed lung, severe allergic reaction or choking.
When to seek emergency help
Use your local emergency medical service immediately if breathing difficulty is severe, begins suddenly and seriously interferes with breathing or speaking, or occurs with blue or gray lips or skin, severe chest pain, confusion, fainting, choking, swelling of the face or throat, or coughing up a significant amount of blood.
Do not wait to see whether severe breathing difficulty improves on its own.
When to arrange medical assessment
Contact a healthcare professional for unexplained breathlessness, especially when it is new, worsening or occurs with mild activity or at rest. Assessment is also important if breathlessness wakes you at night, becomes worse when lying flat, occurs with wheezing, fever, persistent cough, ankle swelling or a clear change from your usual breathing pattern.
How shortness of breath is evaluated
A clinician will ask when the symptoms began, what triggers them and whether other symptoms are present. Assessment may include examination of the heart and lungs and measurement of blood oxygen saturation.
Depending on the suspected cause, tests may include blood tests, an electrocardiogram (ECG), chest X ray, CT imaging, echocardiography, exercise testing or lung function tests.
Treatment
Treatment depends on the cause rather than the sensation of breathlessness itself. Examples include inhaled medicines for asthma or COPD, treatment of an infection when appropriate, medicines for heart disease, anticoagulants for a pulmonary embolism, or treatment of anemia. Oxygen may be needed when blood oxygen levels are too low and should be used according to medical guidance.
Living with long term breathlessness
If breathlessness is related to a diagnosed chronic condition, follow the treatment and action plan provided by your healthcare team. Pulmonary or cardiac rehabilitation, appropriate physical activity, pacing and professionally taught breathing techniques can help some people maintain function and quality of life.
A significant change from your normal breathing should not automatically be attributed to anxiety, aging or poor fitness without appropriate assessment.
Related topics
Sources
- MedlinePlus: Breathing Difficulty
- MedlinePlus: Breathing Problems
- National Heart, Lung, and Blood Institute: Lung Diseases
Last reviewed: 4 September 2026. This page provides general health information and does not replace individual medical advice.