Dyspnea (Shortness of Breath): Meaning, Types and Causes

What dyspnea means

The word comes from Greek: dys (difficult or bad) and pnoia (breathing). The American Thoracic Society defines dyspnea as "a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity". In plain terms, it is how breathing feels to you, which is why two people with the same oxygen level can feel very different.

People describe dyspnea in three main ways, which hint at the cause:

• Air hunger ("I can't get enough air"): common in heart failure, pulmonary embolism and severe lung disease.
• Work or effort ("breathing is hard work"): typical of COPD, asthma and muscle weakness.
• Chest tightness: classic for asthma and bronchospasm.

For a practical guide to causes and emergencies, see shortness of breath.

Types of dyspnea

Causes of dyspnea

Lung causes

• Asthma: episodes of wheeze, cough and chest tightness, often at night or with triggers.
• COPD: slowly worsening breathlessness and cough in current or former smokers.
• Pneumonia and other chest infections: fever, cough and sputum.
• Pulmonary embolism: a clot in the lung arteries causing sudden breathlessness, sometimes with chest pain or a swollen leg.
• Pneumothorax: a collapsed lung, with sudden one-sided chest pain.
• Interstitial lung disease: scarring of the lungs, with a dry cough and crackles.
• Pleural effusion: fluid around the lung.
• Lung cancer.

Heart causes

• Heart failure: breathlessness on exertion, orthopnea, PND and ankle swelling.
• Heart attack and angina: breathlessness can be the main symptom, especially in women, older adults and people with diabetes.
• Heart valve disease, such as aortic stenosis.
• Arrhythmias such as atrial fibrillation.
• Fluid around the heart (pericardial effusion).

Other causes

• Anemia: fewer red cells carry less oxygen.
• Anaphylaxis: throat and airway swelling with hives and low blood pressure.
• Anxiety and panic attacks: rapid breathing, tingling and a sense of being unable to take a satisfying breath. Physical causes should be ruled out first.
• Obesity and deconditioning.
• Pregnancy, especially later stages.
• Neuromuscular diseases affecting the breathing muscles.
• Metabolic acidosis, such as diabetic ketoacidosis, which causes deep, rapid breathing.
• High altitude.

How doctors grade dyspnea

The modified Medical Research Council (mMRC) scale grades breathlessness in daily life:

• Grade 0: breathless only with strenuous exercise
• Grade 1: breathless when hurrying on the level or walking up a slight hill
• Grade 2: walks slower than people of the same age, or has to stop for breath at own pace
• Grade 3: stops for breath after about 100 meters (110 yards) or a few minutes on the level
• Grade 4: too breathless to leave the house, or breathless when dressing

In heart disease, doctors use the NYHA classes I to IV, from no limitation to symptoms at rest. The Borg scale (0 to 10) rates breathlessness during exercise tests.

How dyspnea is assessed

The doctor will ask how quickly it started, what brings it on, whether it is worse lying flat, and about cough, chest pain, wheeze, leg swelling, smoking and work exposures. They will check your breathing rate, oxygen saturation, pulse, blood pressure and listen to your heart and lungs. Tests depend on the likely cause:

• Pulse oximetry and blood gases for oxygen and carbon dioxide levels
• Chest X-ray
• ECG and echocardiogram
• Blood tests: blood count for anemia, BNP for heart failure, D-dimer for clots, and troponin for heart damage
• Spirometry and full lung function tests for asthma and COPD
• CT scan of the chest, including CT pulmonary angiography for suspected clots
• Exercise testing when the cause remains unclear

Treatment

Treatment depends on the cause: inhalers for asthma and COPD, antibiotics for bacterial pneumonia, blood thinners for pulmonary embolism, diuretics and heart medicines for heart failure, iron or other treatment for anemia, and epinephrine for anaphylaxis. Oxygen is given when blood oxygen is low.

For long-term breathlessness, pulmonary rehabilitation (supervised exercise and education) improves symptoms and quality of life in COPD and other lung diseases. Helpful techniques include pursed-lip breathing (in through the nose, out slowly through pursed lips), leaning forward with arms supported, pacing activities and using a handheld fan directed at the face.

Frequently asked questions

What does dyspnea mean?

Dyspnea is the medical term for shortness of breath. It describes an uncomfortable sensation of breathing, such as not getting enough air, chest tightness or breathing feeling like hard work. Doctors use it in notes, for example "dyspnea on exertion", meaning breathlessness during activity.

What is the difference between dyspnea and shortness of breath?

There is no real difference. Dyspnea is the medical word, and shortness of breath or breathlessness is the everyday phrase. Some doctors also use tachypnea for fast breathing and hypoxia for low oxygen, which are measurable signs rather than feelings.

What is dyspnea on exertion?

It means getting breathless with physical activity, such as climbing stairs or walking briskly, but not at rest. Some breathlessness during hard exercise is normal. New or worsening exertional dyspnea, especially if you are more breathless than before, can be an early sign of heart or lung disease or anemia.

What is orthopnea?

Orthopnea is breathlessness when lying flat that improves when sitting up. People often need several pillows or sleep in a chair. It is a classic sign of heart failure because fluid shifts into the lungs when lying down. It can also occur with severe COPD or weak breathing muscles.

Can anxiety cause dyspnea?

Yes. Anxiety and panic attacks often cause a feeling of not getting enough air, fast breathing, chest tightness, tingling and dizziness. Because serious heart and lung problems can feel similar, new breathlessness should be checked by a doctor before it is put down to anxiety.