A pulmonologist is a physician who diagnoses and treats medical conditions that affect the respiratory system.

A primary care physician may refer someone to a pulmonologist if they show signs of having a respiratory health condition. This includes infections such as pneumonia and chronic conditions such as chronic obstructive pulmonary disease (COPD) and asthma.

This article covers what pulmonologists do, what conditions they treat, and more.

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A person may visit a pulmonologist if they have a medical condition that affects the respiratory system.

A pulmonologist is a medical doctor who specializes in the respiratory system. This system includes all organs, airways, and muscles that bring oxygen into and expel carbon dioxide out of the body.

Specifically, the respiratory system includes the:

  • nasal cavity
  • mouth
  • throat, or pharynx
  • voice box, or larynx
  • trachea
  • lungs
  • bronchi
  • bronchioles
  • alveoli

Pulmonologists diagnose and treat respiratory conditions that result from:

  • infections
  • inflammation
  • structural irregularities
  • tumors
  • autoimmune conditions

Certain respiratory conditions, including COPD and interstitial lung disease, can also affect the cardiovascular system. Symptoms such as chest pain and difficulty breathing occur in both cardiovascular and respiratory conditions.

For this reason, pulmonologists often work closely with cardiologists when diagnosing and treating certain conditions.

Pulmonologists also coordinate people’s treatment plans with interdisciplinary healthcare teams comprising specialists, nurses, pathologists, and respiratory therapists.

Pulmonology is a subspecialty of internal medicine or pediatrics specifically dedicated to studying the respiratory system and treating respiratory conditions.

Pulmonologists can further specialize in their practice by only treating specific conditions or focusing on certain patient demographics.

Subspecialties within pulmonology include:

  • critical care medicine
  • sleep-disordered breathing
  • interstitial lung disease
  • obstructive lung disease
  • interventional pulmonology
  • neuromuscular disease
  • lung transplantation

Pulmonologists perform various tests and procedures to diagnose and monitor a number of respiratory conditions. These procedures include:

Imaging tests

Pulmonologists use imaging tests to examine different structures in the lungs and chest. These tests will reveal any structural irregularities causing a person’s respiratory symptoms.

For example, pulmonologists may use the following imaging tests:

  • Chest X-rays. These take images of the lungs. Pulmonologists use chest X-rays to monitor overall lung health, looking for infections such as pneumonia or lung masses such as cancer.
  • Chest CT scans. These provide more detailed X-ray images of the chest and lungs. Pulmonologists can detect signs of emphysema, lung cancer, and pleural effusion using chest CT scans. Pulmonologists also use the scan results to plan their next steps.
  • Chest ultrasound. These use soundwaves to produce images of the structures inside the chest and the pleural space, which is the area between the lungs and the chest wall.

Pulmonary function tests

Pulmonary function tests measure different aspects of respiratory health, including lung volume, oxygen absorption, and inflammation in the lungs. Pulmonologists use the results of these tests to help them diagnose respiratory conditions and monitor the effects of current treatments.

Some pulmonary function tests include:

  • Spirometry. This is the most common type of pulmonary function test. It measures lung capacity and the rate for airflow in and out of the lungs.
  • Lung volume tests. These measure the volume of air in the lungs when a person inhales and exhales.
  • Pulse oximetry. This measures oxygen levels in the blood.
  • Arterial blood gas test. This estimates the levels of oxygen and carbon dioxide in the blood.
  • Fractional exhaled nitric oxide test. This measures the nitric oxide content in a person’s breath. Having high nitric oxide levels usually indicates asthmatic inflammation in the lungs.

Sleep studies

Pulmonologists who specialize in sleep-disordered breathing conditions may conduct sleep studies to diagnose obstructive sleep apnea.

A sleep study, or polysomnogram, records a person’s brain and muscle activity — as well as their eye movement, heart rate, and breathing rate — while they sleep.


A pulmonologist may perform a biopsy to remove a sample of tissue from the lung or the pleura, which is the membrane surrounding the lungs. Biopsies of the lung and pleura may reveal signs of inflammation, infection, or cancer.

Pulmonologists can treat a wide range of medical conditions that affect the respiratory system. These range from infections and chronic immune conditions to cancer and progressive conditions.

Pulmonologists often treat the following:

  • Asthma. This is a chronic condition in which inflammation restricts the airways and causes wheezing, shortness of breath, and coughing.
  • Bronchitis. This refers to inflammation and swelling of the bronchial tubes due to viral or bacterial infections and exposure to irritants, such as dust, chemical fumes, or cigarette smoke.
  • COPD. This includes progressive conditions such as emphysema and chronic bronchitis, which damage or block the airways and air sacs in the lungs. Although smoking is the leading cause of COPD, up to 25% of people with this condition do not have a history of smoking, according to the National Heart, Lung, and Blood Institute.
  • Cystic fibrosis. This is an inherited condition wherein the body produces thick, sticky mucus that can clog the lungs, airways, and pancreas. People with cystic fibrosis have a higher risk of developing persistent lung infections.
  • Emphysema. This is a part of COPD. This condition damages the walls of the air sacs in the lungs, which can cause the air sacs to collapse or stretch beyond their normal capacity.
  • Interstitial lung disease. This refers to a group of conditions that cause scarring, or fibrosis, of the lungs. Fibrosis makes the lungs less elastic, which makes it difficult to breathe.
  • Obstructive sleep apnea. This occurs when a person repeatedly stops breathing for at least 10 seconds during the night. People with sleep apnea may also experience chronic snoring, daytime fatigue, and difficulty concentrating. It can also lead to other complications, such as depression, high blood pressure, or heart attack.
  • Occupational lung disease. This refers to several respiratory issues that occur as a result of long-term exposure to irritating or toxic substances in a work environment. Substances that can cause occupational lung disease include asbestos, crystalline silica, mold, and chemical fumes.
  • Pulmonary hypertension. This condition causes abnormally high blood pressure in the arteries that supply the lungs. Pulmonary hypertension typically develops as a result of other underlying conditions, such as blood clots in the lungs, emphysema, heart failure, or liver disease.
  • Tuberculosis (TB). This occurs when Mycobacterium tuberculosis bacteria get into the lungs. TB can cause persistent coughing, chest pain, and coughing up bloody phlegm. Although infection rates are relatively low in most developed countries, TB is one of the top 10 causes of death worldwide, according to the World Health Organization (WHO).

Pulmonologists must complete the following education requirements:

  • a 4-year undergraduate degree
  • a 4-year medical school degree
  • a 3-year residency in internal medicine
  • a 2- or 3-year fellowship in pulmonology
  • specialized training in critical care or sleep medicine

Pulmonologists must pass board certification exams after completing their fellowship and any additional training. They can officially begin their practice once they receive their certifications.

A pulmonologist is a medical doctor who specializes in diagnosing and treating respiratory conditions, including emphysema, bronchitis, and TB, among others.

A primary care physician may refer someone to a pulmonologist if they have persistent or worsening respiratory symptoms, such as difficulty breathing, chest pain, or a cough that lasts for longer than 3 weeks.