Definition

Few sensations are as frightening as not being able to get enough air. Shortness of breath — known medically as dyspnea — is often described as an intense tightening in the chest, air hunger, difficulty breathing, breathlessness or a feeling of suffocation.

Very strenuous exercise, extreme temperatures, obesity and higher altitude all can cause shortness of breath in a healthy person. Outside of these examples, shortness of breath is likely a sign of a medical problem.

If you have unexplained shortness of breath, especially if it comes on suddenly and is severe, see your doctor as soon as possible.

Causes

Most cases of shortness of breath are due to heart or lung conditions. Your heart and lungs are involved in transporting oxygen to your tissues and removing carbon dioxide, and problems with either of these processes affect your breathing.

Shortness of breath that comes on suddenly (called acute) has a limited number of causes, including:

• Anaphylaxis (a severe allergic reaction)
• Asthma
• Carbon monoxide poisoning
• Cardiac tamponade (excess fluid around the heart)
• COPD (chronic obstructive pulmonary disease) exacerbation — worsening of symptoms
• Coronavirus disease 2019 (COVID-19)
• Heart attack
• Heart arrhythmia (heart rhythm problems)
• Heart failure
• Pneumonia (and other pulmonary infections)
• Pneumothorax (collapsed lung)
• Pulmonary embolism (blood clot in an artery in the lung)
• Sudden blood loss
• Upper airway obstruction (blockage in the breathing passage)

In the case of shortness of breath that has lasted for weeks or longer (called chronic), the condition is most often due to:

• Asthma
• COPD (chronic obstructive pulmonary disease) exacerbation — worsening of symptoms
• Deconditioning
• Heart dysfunction
• Interstitial lung disease
• Obesity
• Pleural effusion (accumulation of fluid around the lungs)

A number of other health conditions also can make it hard to get enough air. These include:

Lung problems

• Croup (especially in young children)
• Lung cancer
• Pleurisy (inflammation of the membrane surrounding the lungs)
• Pulmonary edema (excess fluid in the lungs)
• Pulmonary fibrosis (scarred and damaged lungs)
• Pulmonary hypertension
• Sarcoidosis (collections of inflammatory cells in the body)
• Tuberculosis

Heart problems

• Cardiomyopathy (problem with the heart muscle)
• Heart failure
• Pericarditis (inflammation of the tissue around the heart)

Other problems

• Anemia
• Anxiety disorders
• Broken ribs
• Choking: First aid
• Epiglottitis (swelling of the "lid" of your windpipe)
• Foreign object inhaled: First aid
• Guillain-Barre syndrome
• Kyphoscoliosis (a chest wall deformity)
• Myasthenia gravis (a condition causing muscle weakness)

When to see a doctor

Seek emergency medical care

Call 911 or your local emergency number or have someone drive you to the emergency room if you experience severe shortness of breath that comes on suddenly and affects your ability to function. Seek emergency medical care if your shortness of breath is accompanied by chest pain, fainting, nausea, a bluish tinge to lips or nails, or a change in mental alertness — as these may be signs of a heart attack or pulmonary embolism.

Make a doctor's appointment

Make an appointment with your doctor if your shortness of breath is accompanied by:

• Swelling in your feet and ankles
• Trouble breathing when you lie flat
• High fever, chills and cough
• Wheezing
• Worsening of preexisting shortness of breath

Self-care

To help keep chronic shortness of breath from getting worse:

• Stop smoking. Quit smoking, or don't start. Smoking is the leading cause of COPD. If you have COPD, quitting can slow the progression of the disease and prevent complications.
• Avoid exposure to pollutants. As much as possible, avoid breathing allergens and environmental toxins, such as chemical fumes or secondhand smoke.
• Avoid extremes in temperature. Activity in very hot and humid or very cold conditions may magnify the dyspnea caused by chronic lung diseases.
• Have an action plan. If you have a medical condition that causes shortness of breath, discuss with your doctor what to do if your symptoms become worse.
• Keep elevation in mind. When traveling to areas with higher altitude, take time to adjust and avoid exertion until then.
• Exercise regularly. Exercise can help improve physical fitness and the ability to tolerate activity. Exercise — along with weight loss if you're overweight — may help decrease any contribution to shortness of breath from deconditioning. Talk to your doctor before starting an exercise program.
• Take your medications. Skipping medications for chronic lung and cardiac conditions can lead to poorer control of dyspnea.
• Regularly check your equipment. If you rely on supplemental oxygen, be sure your supply is adequate and the equipment works properly.