A person who exercises regularly, maintains a healthy weight and rarely falls ill may seem like the picture of good health. But when it comes to the lungs, appearance and fitness do not always tell the complete story.

Some respiratory diseases develop gradually, allowing the body to compensate for declining lung function for a considerable period. A person may remain active while slowly needing more breaks during exercise, struggling with stairs or noticing that a cough is taking longer to disappear. Such changes may be blamed on ageing, pollution, stress or being "out of shape".

This World Lung Day 2026, respiratory health experts are emphasising the importance of recognising changes in breathing and lung function rather than relying on outward appearance. The Forum of International Respiratory Societies (FIRS), which coordinates World Lung Day, has chosen "A Lifetime of Lung Health" as this year's theme, highlighting the need to protect respiratory health at every stage of life.

"Lung health cannot always be judged by appearance," said Dr Nikhil Modi, Senior Consultant, Respiratory Medicine, Indraprastha Apollo Hospitals, New Delhi. He explains why seemingly healthy people can have underlying lung disease and which symptoms should not be dismissed.

Why can lung disease go unnoticed?

"The lungs have a considerable reserve, so the body can compensate for reduced lung function for some time," Dr Modi said. "As a result, symptoms may initially appear only during strenuous activity and become more noticeable as the condition progresses."

This can make early respiratory disease particularly easy to overlook. Chronic obstructive pulmonary disease (COPD), for example, develops gradually and commonly causes breathlessness, chronic cough, mucus production and tiredness. WHO estimates that COPD caused 3.4 million deaths globally in 2023, making it the world's third leading cause of death.

Asthma can also affect people who otherwise appear healthy. WHO estimates that 363 million people had asthma in 2023, with symptoms including cough, wheezing, shortness of breath and chest tightness. Symptoms can come and go, sometimes becoming more noticeable during exercise or at night.

Lung disease is not only a smoker's problem

Smoking is a major risk factor, but it is not the only threat to lung health. "Smoking is an important risk factor, but it is not the only one," Dr Modi said. "Secondhand smoke, air pollution and exposure to dust or chemicals at work can also affect the lungs."

WHO identifies tobacco smoke, air pollution and occupational exposure to dust, fumes and chemicals among important risk factors for chronic respiratory diseases.

This is particularly relevant in India, where people can encounter multiple sources of exposure, including outdoor air pollution, household smoke and workplace pollutants. WHO estimates that air pollution contributes to around 7 million premature deaths globally each year, through conditions including COPD, lung cancer, respiratory infections, heart disease and stroke.

"Respiratory infections, allergies and certain underlying conditions may contribute to breathing problems," Dr Modi added.

These lung symptoms should not be ignored

Rather than judging lung health by body weight or fitness level, Dr Modi recommends paying attention to changes in breathing and exercise capacity.

Warning signs include:

  • Breathlessness during activities that were previously comfortable
  • A persistent or recurring cough
  • Wheezing or chest tightness
  • Excess mucus or repeated respiratory infections
  • An unexplained reduction in stamina
  • Coughing up blood

A particularly important clue is a gradual change in what a person can comfortably do. "Needing more breaks during exercise or avoiding activities because of breathlessness should not automatically be dismissed as poor fitness," Dr Modi said.

A persistent cough or breathlessness can have many causes, including infections, asthma, COPD, allergies, heart disease and other conditions. Therefore, these symptoms do not automatically indicate serious lung disease. However, persistent or recurrent symptoms warrant medical assessment rather than repeated self-treatment.

Coughing up blood, particularly when unexplained, requires prompt medical attention.

When should you get your lungs checked?

Persistent respiratory symptoms should be evaluated by a doctor, particularly when they interfere with daily activities or represent a change from a person's usual exercise capacity.

"A doctor may assess the pattern of symptoms, medical and occupational history, smoking or pollution exposure and oxygen levels," Dr Modi said. Depending on the clinical findings, investigations may include spirometry, chest imaging and other pulmonary function tests.

Spirometry is particularly important when COPD is suspected. WHO recommends confirming a suspected COPD diagnosis with spirometry, which measures how effectively the lungs move air.

The test can help determine whether symptoms are related to airflow obstruction. Other tests may be required depending on whether the doctor suspects a problem involving the airways, lung tissue, blood vessels or another part of the respiratory system.

How is lung disease treated?

There is no single treatment for all lung diseases. Management depends on the diagnosis, severity and underlying cause.

For conditions such as asthma and COPD, inhaled medicines may be prescribed. Bronchodilators help open narrowed airways, while inhaled corticosteroids may be used in conditions where airway inflammation needs to be controlled. WHO notes that inhaled medicines can effectively control asthma symptoms, while COPD treatment may include medicines, oxygen and pulmonary rehabilitation.

Some people with advanced lung disease may require long-term oxygen therapy or specialised procedures. In selected cases of end-stage lung disease, transplantation may be considered.

Treatment can also involve removing or reducing the trigger. For smokers, quitting tobacco is particularly important. Avoiding occupational dust and fumes and reducing exposure to polluted air can also form part of respiratory disease management.

How can you protect your lungs?

"Healthy lung habits are useful even when there are no symptoms," Dr Modi said.

He recommends:

  • Not smoking and avoiding second-hand smoke
  • Reducing exposure to dust, fumes and chemical irritants
  • Using appropriate protective equipment in high-risk workplaces
  • Staying physically active according to individual health and fitness levels
  • Not ignoring a cough or breathlessness that persists or repeatedly returns
  • Seeking medical evaluation when exercise tolerance changes without an obvious reason

WHO's integrated approach to lung health similarly emphasises prevention, early diagnosis, appropriate treatment and long-term disease management.

Lung disease does not always have an obvious outward appearance. Someone can look fit, maintain a healthy weight and continue exercising while an underlying respiratory condition develops gradually.

The more useful markers are changes in breathing, stamina and respiratory symptoms. Breathlessness that is new or worsening, a persistent cough, wheezing, repeated respiratory infections, unexplained mucus production or coughing up blood should not simply be attributed to ageing, pollution or poor fitness.

"Lung disease does not always have an obvious outward appearance," Dr Modi said. "The more useful measure is whether breathing, stamina or respiratory symptoms have changed." On World Lung Day 2026, the message is therefore simple: protect your lungs throughout life, know your normal breathing capacity and pay attention when it changes.



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