Causes, symptoms, and diagnosis of shortness of breath

Shortness of breath It happens when you breathe faster than usual. Normal breathing rate may vary with age and activity. For most adults, it is usually 12 to 20 breaths per minute at rest.

hyperventilation Describes rapid, deep breathing, while tachypnea refers to rapid, shallow breathing.

This article looks at potential causes of shortness of breath, as well as medical conditions that may occur.


Shortness of breath may be accompanied by other symptoms, such as:

  • Dyspnea: shortness of breath and a feeling of not being able to get enough air
  • Cyanosis: blue fingers and lips
  • Contraction: Breathe into the chest muscles

Shortness of breath may also not have any obvious symptoms. This is common when it is related to the following conditions:

  • metabolic imbalance
  • Central Nervous System Conditions

shortness of breath and difficulty breathing

Some people with shortness of breath may experience shortness of breath. Others may not notice any breathing difficulties at all.

dyspnea means feel Short of breath.

Dyspnea can occur at normal, high, or low respiratory rates. It can also occur in shallow breathing mode or deep breathing mode.

Causes of shortness of breath

Shortness of breath has physiological and pathological causes.

This video has been medically reviewed by Sanja Jelic, MD.

physiological reasons

Physiological causes refer to the normal ability of the body to correct abnormal conditions. Shortness of breath itself is not an abnormal physical response. Rather, it’s a normal response to something abnormal happening in the body.

Shortness of breath can be caused by three main physiological processes:

  • Imbalance between breathing gases: low oxygen levels in the blood called hypoxemia. An increase in the amount of carbon dioxide in the blood is called hypercapnia. Both conditions can cause shortness of breath.
  • Acid-base imbalance: When the body senses that the blood is too acidic, it pushes carbon dioxide out of the lungs to remove acid from the body. It can also cause shortness of breath.
  • Fever: When you have a fever, your breathing becomes faster as your body tries to release heat.
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In these examples, shortness of breath is not abnormal. Rather, it’s how the body compensates for the abnormality.

Pathological cause

The pathological cause is not an effort to restore balance in the body. Instead, the opposite is true.

For example, you may experience shallow, rapid breathing due to anxiety or fear. It’s not something your body does to restore balance.


Shortness of breath occurs when your body tries to correct an abnormal situation, such as an imbalance of carbon dioxide and oxygen. It can also be a reaction to external things, such as anxiety or fear.

Conditions that can cause shortness of breath

A wide range of medical conditions can cause shortness of breath. These may include:

  • Lung-related disease: Lung disease may lower oxygen levels or raise carbon dioxide levels. Take quick breaths to try to bring these levels back to normal. These conditions include chronic obstructive pulmonary disease (COPD), asthma, pneumonia, pulmonary fibrosis, collapsed lung, pulmonary embolism, and the like.
  • Heart-related diseases: Conditions such as heart failure, anemia, or an underactive thyroid can cause cardiovascular changes that can lead to shortness of breath.
  • Hyperventilation: This can be due to pain, anxiety, or other conditions.
  • Metabolic acidosis: When blood acid levels are too high, the breathing rate increases to expel carbon dioxide.Some reasons for this include diabetic ketoacidosislactic acidosis, and liver encephalopathy.
  • CNS-related disorders: Shortness of breath can be caused by abnormalities in the brain, such as a brain tumor.
  • Use of certain drugs: Drugs such as aspirin, stimulants, and marijuana can cause rapid, shallow breathing.

In hospitalized patients, shortness of breath may be a sign that pneumonia is developing. This symptom usually occurs before other obvious signs of pneumonia.

shortness of breath and lung cancer

Lung cancer can cause shortness of breath in several different ways. Lung damage disrupts the normal exchange of oxygen and carbon dioxide. Scarring, such as from lung cancer surgery, can also lead to a decrease in the ability to take in oxygen.

Anemia from chemotherapy can worsen shortness of breath. When there are fewer red blood cells that carry oxygen, breathing becomes faster in an attempt to correct the situation.

Diagnosing shortness of breath

Diagnosis of shortness of breath varies by age, other medical problems, current medications, and other symptoms. Some diagnostic tools may include:

  • Oximetry: A “clip” can be placed on your finger to estimate the amount of oxygen in your blood.
  • Arterial blood gases (ABG): These measure oxygen levels, carbon dioxide levels, and blood pH. pH helps to look for problems with the body’s metabolic processes. If the pH is low, tests can be done to look for causes such as high levels of acid in the blood and liver problems.
  • Chest X-ray: X-rays can quickly find some causes of shortness of breath, such as a collapsed lung.
  • Computed tomography (CT) scan of the chest: This can be used to look for lung disease or tumors.
  • Pulmonary function tests: These tests are useful when looking for conditions such as COPD and asthma.
  • Glucose: When your body produces too much blood acid called ketones, a blood sugar test is usually done to rule out or confirm diabetic ketoacidosis.
  • Electrolytes: Sodium and potassium levels can help assess some causes of shortness of breath.
  • Hemoglobin: A complete blood count and hemoglobin test can be done to look for evidence of anemia and infection.
  • Electrocardiogram (EKG): An EKG can look for evidence of a heart attack or abnormal heart rhythm.
  • VQ scan: This test measures how air moves in and out of your lungs. It also measures blood flow to the lungs. This is usually done if the blood clot has the potential to block one of the arteries that carry blood to the lungs.
  • Magnetic resonance imaging (MRI) of the brain: If no obvious cause of shortness of breath is found, MRI of the brain may be helpful. This can help rule out brain abnormalities, such as tumors.
  • Toxicology Screening: Many drugs can cause shortness of breath, including prescription, over-the-counter, and illegal drugs. In an emergency, if the cause of shortness of breath is unknown, toxicology screening is usually done.


Doctors can use a variety of diagnostic tools to find the cause of shortness of breath. These may include various imaging scans and blood tests.

How to treat shortness of breath

Treatment of shortness of breath depends on finding and correcting the underlying cause.


Shortness of breath describes abnormally rapid breathing. This is different from dyspnea, which makes you feel like you’re not getting enough air.

You may experience shortness of breath because your body is trying to correct an abnormality that is going on in your body. It can also be caused by external factors, such as fear or anxiety.