What causes shortness of breath?

Many different medical disorders can cause shortness of breath. The most common causes are lung and heart conditions. Healthy breathing depends on these organs to transport oxygen to your body.

Feeling breathless may be acute, lasting just a few days or less. Other times, it is chronic, lasting longer than three to six months.

What causes ongoing shortness of breath?

Conditions that may cause chronic shortness of breath include:

  • Asthma: Narrowing of the airways caused by asthma can make it feel difficult to breathe.
  • Heart failure: During heart failure, blood can’t fill and empty the heart properly. This condition may cause fluid to accumulate in your lungs, making it feel difficult to breathe.
  • Lung disease: Damage to lung tissue from diseases such as tobacco smoking-related chronic obstructive pulmonary disease (COPD) can cause dyspnea. Tumors, such as lung cancer, can also cause shortness of breath.
  • Obesity: Being very overweight can strain your lungs and make it difficult to breathe.
  • Poor fitness: Being out of shape from inactivity or illness can cause breathlessness.

What causes acute dyspnea or shortness of breath?

Factors that may cause acute (goes away after a week or so) shortness of breath include:

  • Allergies: People often feel short of breath during an allergic reaction.
  • Anxiety: Anxiety can cause hyperventilation (rapid, heavy breathing).
  • Choking: A blockage in your throat can make it difficult for air to move in and out of your lungs. Inhaling food or an object into your lungs also blocks airflow.
  • Pulmonary embolism: This happens when you have a blood clot in your lungs. This condition is a medical emergency.
  • Heart attack: A blockage that stops blood flow to the heart can cause frightening breathlessness. If you notice this symptom along with other heart attack symptoms, call 911.
  • Infection: An infection like bronchitis or pneumonia may produce mucous that blocks airflow to parts of the lungs. This can interfere with oxygen diffusion to the blood.
  • Injury: A broken rib can make breathing painful and difficult. Bleeding and anemia can lower the number of red blood cells, which lessens the amount of oxygen carried in the blood.
  • Medication: Certain medicines can cause a tight feeling in the chest. Statins (medicines that reduce fats in the blood) and beta blockers given for hypertension in asthmatic individuals may cause this symptom.
  • Extreme temperatures. Being very hot or very cold can make you feel like you are having trouble breathing.

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