Respiratory Health: The Complete Guide

How your lungs work, what harms them, how asthma, COPD and chest infections are recognized and managed, and the practical steps, from quitting smoking to checking the air quality, that protect your breathing. Written for adults looking after their own lungs and for parents and caregivers of children and older relatives.

Key numbers at a glance

How your lungs and airways work

Every breath travels through your nose or mouth, down the windpipe, and into two main airways that divide again and again into smaller branches, like an upside-down tree. The smallest branches end in tiny air sacs called alveoli, wrapped in a mesh of fine blood vessels. There, oxygen passes into your blood and carbon dioxide, the waste gas your body makes, passes out to be breathed away. The total surface for this exchange is huge, which is how a pair of organs inside your chest can supply every cell in your body.

Breathing is driven mainly by the diaphragm, a dome-shaped muscle beneath the lungs, helped by muscles between the ribs. You rarely think about it because your brain adjusts your breathing automatically, responding mostly to the level of carbon dioxide in your blood. That is why you breathe faster when you exercise, and also why anxiety, which changes breathing patterns, can make you feel short of breath even when your lungs are healthy.

Because the lungs are open to the outside world, they have layers of defense. Hairs and mucus in the nose trap larger particles. The airways are lined with sticky mucus and tiny hair-like structures called cilia, which sweep trapped dust and germs upward so they can be swallowed or coughed out. Coughing clears what the cilia cannot, and immune cells patrol the air sacs. Tobacco smoke damages the cilia, which is one reason smokers cough more and get more chest infections.

Why lung health matters and what harms it

Lung function grows through childhood, peaks in early adulthood and then declines slowly with age. Your lungs also have a great deal of spare capacity, which is both a strength and a trap: they can lose a large share of their function before you notice anything during ordinary daily life. By the time someone with COPD becomes breathless climbing stairs, the damage has usually been building for years. Protecting your lungs is therefore about the long term, and the earlier you start, the more you keep.

The biggest single cause of lung damage in the US is smoking, which causes most cases of COPD and most lung cancers. Other important harms include secondhand smoke, outdoor air pollution and wildfire smoke, indoor sources such as radon, mold and some cooking and heating fuels, workplace dusts, fumes and chemicals, and repeated or severe infections, particularly in early childhood. Genetics play a part too, including a rare inherited condition called alpha-1 antitrypsin deficiency that can cause COPD in people who have never smoked.

Healthy lungs matter far beyond breathing. Long-term lung disease limits activity, which affects muscles, the heart, mood and independence. Low oxygen levels put strain on the heart. Lung and heart problems often occur together and share symptoms, so new breathlessness is always worth investigating rather than assuming it is your lungs or your fitness. Looking after your lungs and your heart is, in practice, the same project.

Asthma

Asthma is a long-term condition in which the airways are inflamed and oversensitive. When they meet a trigger, the muscles around them tighten, the lining swells and extra mucus is produced, narrowing the passages air must travel through. That causes the classic symptoms: wheezing, coughing, chest tightness and shortness of breath, often worse at night, early in the morning or with exercise. Asthma affects children and adults, and it can start at any age.

The goal of asthma care is good control, which means few or no symptoms, no limits on normal activity, and no attacks. Many people accept far worse than that because they have grown used to it. A useful sign that asthma is not well controlled is needing your quick-relief inhaler more than two days a week. Waking at night with symptoms, missing work or school, or needing an urgent care visit are also signals to see your doctor and review your treatment.

Controller and quick-relief medicines

Asthma medicines fall into two groups. Quick-relief, or rescue, inhalers contain a short-acting bronchodilator such as albuterol, which relaxes the airway muscles within minutes but does nothing about the underlying inflammation. Controller medicines, most often an inhaled corticosteroid, reduce that inflammation over time and are taken as prescribed even when you feel well. One of the most common dangerous patterns is relying on the rescue inhaler while skipping the controller. Some people are prescribed a single combination inhaler used as both controller and reliever; follow the plan your doctor gives you.

Inhaler technique matters as much as the medicine. Many people do not get the full dose into their lungs because of timing, speed of breathing or not holding their breath afterward. A spacer or valved holding chamber used with a metered-dose inhaler helps more of the medicine reach the airways. Ask your doctor, nurse or pharmacist to watch you use your inhaler at each visit.

Your asthma action plan

Everyone with asthma should have a written asthma action plan, worked out with their doctor. It lists your daily medicines, how to recognize when your asthma is getting worse, what to do about it, and when to get emergency help. Many plans use green, yellow and red zones based on symptoms or peak flow readings. Keep copies at home, at work and, for children, at school and with anyone who cares for them, and update it after any attack or change in treatment.

Triggers and allergies

Common triggers include colds and flu, tobacco smoke, pollen, dust mites, mold, pet dander, cold air, exercise, strong smells, and air pollution. Some people react to medicines such as aspirin and other NSAIDs or beta blockers. Hay fever, seasonal allergic rhinitis, often makes asthma harder to control, and treating it well, usually with a daily corticosteroid nasal spray started before the pollen season, can help both. Exercise is good for people with asthma; if it triggers symptoms, that usually means your treatment needs adjusting, not that you should stop.

COPD

Chronic obstructive pulmonary disease, COPD, is a long-term lung disease in which the airways are narrowed and the air sacs are damaged, so air cannot flow out of the lungs easily. It includes the conditions once called emphysema and chronic bronchitis. Most COPD is caused by smoking, though long-term exposure to dust, fumes, air pollution and secondhand smoke, and the inherited condition alpha-1 antitrypsin deficiency, also contribute. It usually appears from middle age onward and develops slowly.

Early symptoms are easy to put down to age or being out of shape: breathlessness on exertion, a daily cough, often with mucus, frequent chest infections and wheezing. Many people have COPD for years before it is diagnosed. The diagnosis is made with spirometry, a simple breathing test in which you blow hard and fast into a tube to measure how much air you can push out and how quickly. Anyone with a smoking history and ongoing breathlessness or cough should ask about it.

COPD damage is not reversible, but its course can be changed a great deal. Quitting smoking is by far the most important step at any stage, slowing the decline in lung function. Inhaled medicines widen the airways and reduce flare-ups, and some people need oxygen therapy. Vaccinations are especially important because chest infections are a common trigger for flare-ups, and staying active keeps the muscles you breathe and move with stronger.

Pulmonary rehabilitation

Pulmonary rehabilitation is a supervised program of exercise, breathing techniques and education, usually run over several weeks. It improves breathlessness, exercise capacity and quality of life for many people with COPD, and it is one of the most effective treatments available, yet it is underused. Breathlessness makes people avoid activity, which weakens their muscles so that the same tasks become harder, and rehabilitation breaks that cycle. Medicare covers pulmonary rehabilitation for people with moderate to very severe COPD who have a referral from their doctor. Ask whether it is right for you.

Breathing techniques and flare-ups

Pursed-lip breathing, breathing in through the nose and out slowly through pursed lips, can slow your breathing and help keep the airways open longer. Leaning forward with your arms supported can ease breathlessness. These techniques help with everyday breathlessness, but they never replace your medicines or emergency treatment. A written COPD action plan tells you how to recognize a flare-up, such as more breathlessness or a change in the color or amount of mucus, and what to do, including when to start any standby medicines your doctor has prescribed.

Chest infections and the vaccines that prevent them

Most coughs and colds are caused by viruses and get better on their own. A chest cold, or acute bronchitis, causes a cough that usually improves within three weeks, though a cough after a viral infection can linger for several weeks. Antibiotics do not help viral infections and can cause side effects, so rest, fluids and acetaminophen (Tylenol) or ibuprofen for fever and aches, if they are safe for you, are usually the right approach. Honey can soothe a cough in adults and children over one year old, but never give honey to a baby under one.

Pneumonia is an infection of the lung tissue itself, caused by bacteria, viruses or occasionally fungi. It typically causes a cough with mucus, fever, chills, breathlessness and chest pain on breathing in, and it can be serious, particularly for babies, older adults and people with long-term conditions. In older adults, new confusion may be the main or only sign. Bacterial pneumonia is treated with antibiotics, which should be taken exactly as prescribed; contact your doctor if you are not improving within a few days.

Vaccines prevent many of the infections that cause serious chest illness. A flu vaccine is recommended every year for everyone 6 months and older. Pneumococcal vaccination, which protects against a common cause of bacterial pneumonia, is recommended for adults 50 and older and for younger people with certain medical conditions. RSV vaccination is recommended for some older adults and during pregnancy to protect newborns, and infants can receive protective antibodies. COVID-19 and whooping cough vaccines also protect the lungs. Recommendations change, so ask your doctor or pharmacist which vaccines you need.

Symptoms that need checking, and lung cancer

Breathlessness that is new or getting worse is an important symptom and is often wrongly put down to being out of shape or getting older. It can come from the lungs, the heart, anemia, a blood clot, being overweight or anxiety, among other causes. Breathlessness that comes on suddenly always needs urgent assessment. Breathlessness when lying flat or that wakes you at night can be a sign of heart failure, and breathlessness with one-sided calf pain or swelling can be a sign of a blood clot in the lung.

A cough that lasts more than three weeks should be checked by your doctor. Common causes include asthma, postnasal drip, acid reflux, a lingering infection and some blood pressure medicines called ACE inhibitors, which can cause a dry cough. A persistent cough is also one of the most common symptoms of lung cancer. Coughing up blood, in any amount, always needs prompt medical assessment.

Lung cancer is the leading cause of cancer death in the US, largely because it is often found late, when symptoms such as pain have developed. Symptoms to report include a cough that does not go away or gets worse, coughing up blood, chest or shoulder pain, hoarseness, unexplained weight loss, tiredness, and repeated chest infections. Smoking is the largest risk factor, and radon is the leading cause among people who have never smoked.

Lung cancer screening

The US Preventive Services Task Force recommends a yearly low-dose CT scan for adults aged 50 to 80 who have a 20 pack-year smoking history and either smoke now or quit within the past 15 years. A pack-year is the number of packs smoked per day multiplied by the number of years; one pack a day for 20 years, or two packs a day for 10, both make 20. Screening finds cancers earlier, when treatment is more likely to work, but it can also find harmless spots that lead to more tests, so it is a decision to talk through with your doctor. Medicare and most private plans cover screening for people who qualify, though the age range can differ slightly by plan.

Smoking, vaping and quitting

Tobacco smoke paralyzes and destroys the cilia that clean your airways, inflames the airway lining, breaks down the walls of the air sacs and causes mutations that lead to cancer. Secondhand smoke harms the lungs of everyone nearby, and there is no safe level of exposure. Children living with smokers have more asthma attacks, ear infections and chest infections. Making your home and car completely smoke-free protects them even if you are not ready to quit.

Quitting brings benefits at any age, and it is never too late. Coughing and shortness of breath tend to improve in the months after quitting, the risk of lung cancer falls steadily over the years, and in COPD quitting slows the loss of lung function more than any medicine. The most effective approach combines counseling with FDA-approved quit medicines: nicotine replacement in the form of patches, gum or lozenges, varenicline and bupropion. Using medicine and support together gives you a much better chance of success than willpower alone, and most people need several attempts, so a relapse is a reason to try again rather than give up.

E-cigarettes are not FDA-approved as quit aids, and the long-term effects of breathing in their aerosol are still being studied. They are not safe for young people, pregnant people, or adults who do not already use tobacco. If you smoke and are considering switching, talk to your doctor about the approved options first, and if you do switch, aim to stop smoking completely rather than doing both.

• Call 1-800-QUIT-NOW for free coaching and help making a quit plan
• Ask your doctor or pharmacist which quit medicines suit you, and use them for the full recommended course
• Set a quit date, tell the people around you, and remove cigarettes from your home and car
• Plan for your trigger situations, such as coffee, alcohol, stress or driving
• Talk to your doctor before using quit medicines if you are pregnant or take medicines such as clozapine or theophylline, whose levels can change when you stop smoking

The air you breathe

Outdoor air pollution, particularly fine particle pollution and ozone, is linked to worse asthma and COPD and to heart problems. The Air Quality Index, or AQI, published at AirNow, turns pollution levels into a single number and color for your area. Values above 100 are unhealthy for sensitive groups, which include people with lung or heart disease, children, older adults and people who are active outdoors. On those days, sensitive groups should shorten or move strenuous outdoor activity indoors, and as the number climbs higher, everyone should cut back.

Wildfire smoke can affect air quality hundreds of miles from a fire. When smoke is heavy, stay indoors with windows and doors closed, run air conditioning on recirculate if you have it, and consider a portable air cleaner with a HEPA filter for the room you spend most time in. A well-fitted N95 respirator gives much better protection outdoors than a cloth or surgical mask. People with asthma or COPD should keep their medicines on hand and follow their action plan.

Indoor air matters just as much, because most people spend most of their time inside. Smoke from tobacco, wood stoves and fireplaces, fumes from cooking, especially on gas stoves without ventilation, dampness and mold, and some cleaning and hobby products all affect the lungs. Using a range hood that vents outside, opening a window while cooking, running a bathroom fan after showering, and fixing leaks quickly all help.

Radon and carbon monoxide

Radon is an invisible, odorless radioactive gas that seeps into homes from the ground, and it is the second leading cause of lung cancer in the US after smoking. The only way to know your level is to test, using an inexpensive kit or a professional. The EPA recommends fixing your home if the level is 4 picocuries per liter (pCi/L) or more. Carbon monoxide, from faulty furnaces, generators, grills or car exhaust, can kill quickly; install carbon monoxide alarms near sleeping areas and never run a generator or grill indoors or in a garage.

At work

Many jobs expose workers to dusts, fumes, gases or chemicals that can harm the lungs, including silica in construction and stone work, asbestos in older buildings, and agents that can cause occupational asthma. Employers are required to control these hazards. Use the protective equipment provided, ask for training, and tell your doctor what you do for a living, especially if your symptoms improve on days off or vacations, which can be a clue that something at work is the cause.

How your lungs are checked, and talking to your doctor

Assessment usually starts with questions and an examination: what your symptoms are and when they happen, your smoking and work history, your home environment, and listening to your chest. A pulse oximeter clipped to your finger estimates the oxygen level in your blood. These devices are useful, but the FDA has warned that they can be less accurate in some situations, including in people with darker skin and with cold hands or nail polish, so a reading should never be the only reason to ignore symptoms that worry you.

Spirometry is the key test for diagnosing asthma and COPD, sometimes repeated after an inhaler to see whether airflow improves. Peak flow meters are simple handheld devices some people with asthma use at home to track their airways. Chest X-rays and CT scans show the structure of the lungs, allergy testing can identify triggers, and a sleep study may be suggested if loud snoring and daytime sleepiness point to sleep apnea.

You will get more from an appointment if you describe exactly what you can no longer do, such as walking up one flight of stairs without stopping, rather than giving a general rating. Note whether symptoms are worse at night, lying flat, with exercise, at work or in particular seasons. Bring all your inhalers and medicines, including over-the-counter products, and ask your doctor to check your inhaler technique and whether you need a written action plan or a referral to pulmonary rehabilitation.

Costs and access

Inhalers can be expensive, and cost is a common reason people skip controller medicines. If yours are hard to afford, tell your doctor or pharmacist; there may be a lower-cost generic or alternative, a different preferred drug on your plan, or a manufacturer assistance program. Preventive services such as recommended vaccines and lung cancer screening for people who qualify are generally covered without a copay under most plans and Medicare. Community health centers offer care on a sliding fee scale for people without insurance.

Children, pregnancy, older adults and other groups

Children's airways are small, so infections and inflammation narrow them quickly. Signs that a child is struggling to breathe include very fast breathing, the skin pulling in between or under the ribs or at the base of the throat with each breath, flaring nostrils, grunting, a bluish or gray color around the lips, and being unusually drowsy or limp. These need emergency care. Common conditions include croup, with its barking cough, bronchiolitis in babies, often caused by RSV, and asthma, which should have an action plan shared with school.

During pregnancy, keep taking your asthma medicines as prescribed. Poorly controlled asthma poses more risk to you and your baby than the medicines usually used to treat it, and pregnancy can change how asthma behaves, so review your plan with your doctor early. Quitting smoking is one of the most important things you can do for your baby's lungs, and the flu vaccine is recommended during pregnancy. Talk to your doctor or pharmacist before using any quit medicine while pregnant.

In older adults, chest infections can show up as confusion, a fall or loss of appetite rather than fever and cough, and they can become serious quickly. Keeping vaccinations up to date, staying active, and asking for any new breathlessness to be checked all matter more with age. People with heart disease, diabetes, a weakened immune system, or conditions affecting swallowing or muscle strength are also at higher risk of serious chest infections and should get same-day advice for fever with breathlessness.

Myths and what the guidance actually says

Breathing problems attract a lot of folk wisdom, and some of it leads people to delay care or use treatments that do not help. The list below sets common beliefs against what US guidance supports. The thread running through all of them is that breathlessness and a lasting cough are symptoms to explain and treat, not just something to live with or work around.

• Myth: if your asthma is quiet, you can stop your controller. Guidance: controllers keep inflammation down, so take them as prescribed and discuss any change with your doctor.
• Myth: using the rescue inhaler often is fine as long as it works. Guidance: needing it more than two days a week is a sign your asthma is not well controlled.
• Myth: a smoker's cough is normal. Guidance: a cough lasting more than three weeks needs checking, whatever your smoking history.
• Myth: it is too late to quit once you have COPD. Guidance: quitting slows lung damage at any stage.
• Myth: antibiotics help a chest cold get better faster. Guidance: most chest colds are viral, and antibiotics do not help them.
• Myth: people with lung disease should avoid exercise. Guidance: staying active, ideally with pulmonary rehabilitation, improves breathlessness.
• Myth: vaping is harmless water vapor. Guidance: e-cigarette aerosol contains nicotine and other chemicals and is not safe for young people or nonsmokers.

A practical four-week plan

This plan focuses on the steps that make the most difference to most people, one week at a time. Adapt it to your own situation; if you have a lung condition, check any changes with your doctor first. Over the longer term, keep up yearly flu vaccination and your other recommended vaccines, review your action plan and inhaler technique at least once a year, retest for radon every few years or after major renovations, and ask each year whether you qualify for lung cancer screening.

• Week 1, take stock: write down any breathlessness, cough or wheeze and when it happens. If you have asthma or COPD, find your action plan or ask for one, and count how often you use your rescue inhaler. Book a visit for any cough lasting more than three weeks.
• Week 2, smoke and vaccines: if you smoke, set a quit date and call 1-800-QUIT-NOW. Make your home and car smoke-free. Check which vaccines are due for you and your family, and book them with your doctor or pharmacist.
• Week 3, your home: order a radon test kit, check that carbon monoxide alarms work, use a vented range hood or open a window while cooking, and deal with any damp or mold. Sign up for air quality alerts at AirNow.
• Week 4, move: build up regular activity, such as daily walks, at a pace that leaves you slightly breathless but able to talk. If lung disease limits you, ask your doctor about pulmonary rehabilitation, and practice pursed-lip breathing when you are calm.

Every guide in this topic

• The Evidence on Asthma, Without the Hype
• What the Guidance Really Says About COPD
• What the Guidance Really Says About Breathlessness
• Persistent Cough: What the Evidence Actually Says
• Smoking and the Lungs: Sorting the Evidence From the Noise
• Air Quality: What the Evidence Actually Says
• The Evidence on Pneumonia, Without the Hype
• Breathing Exercises: What Published Guidance Supports
• Hay Fever: What Published Guidance Supports
• Lung Cancer Awareness: What the Evidence Actually Says

Frequently asked questions

How do I know if my asthma is well controlled?

Well-controlled asthma means few or no symptoms, no limits on normal activity and no attacks. Needing your quick-relief inhaler more than two days a week, waking at night with symptoms, or missing work or school because of asthma are signs it is not well controlled. See your doctor to review your medicines, inhaler technique and action plan.

Is shortness of breath just a sign of being out of shape?

Sometimes, but it should not be assumed. New or worsening breathlessness can come from asthma, COPD, heart problems, anemia or a blood clot. See your doctor for breathlessness on mild exertion, when lying flat or that wakes you at night. Call 911 for sudden severe breathlessness, chest pain, blue or gray lips, or being unable to speak in full sentences.

When should I see a doctor about a cough?

See your doctor for a cough that lasts more than three weeks, and sooner for coughing up blood, unexplained weight loss, night sweats, chest pain, hoarseness that does not go away, or increasing breathlessness. Most coughs after a cold improve within three weeks, though some linger longer. A persistent cough is also a common symptom of lung cancer, so do not ignore it.

Do I qualify for lung cancer screening?

US guidelines recommend a yearly low-dose CT scan for adults aged 50 to 80 with a 20 pack-year smoking history who smoke now or quit within the past 15 years. Work out your pack-years by multiplying packs per day by years smoked. If you might qualify, ask your doctor to talk through the benefits and possible harms, and check your coverage.

Can COPD be reversed?

The lung damage in COPD cannot be reversed, but its course can be changed considerably. Quitting smoking slows the decline in lung function more than anything else. Inhaled medicines ease symptoms and reduce flare-ups, pulmonary rehabilitation improves breathlessness and quality of life, and vaccines help prevent infections that trigger flare-ups. Many people with COPD stay active for years.

Do I need antibiotics for a chest cold?

Usually not. Most chest colds, or acute bronchitis, are caused by viruses, and antibiotics do not help them. They can also cause side effects. Rest, fluids and over-the-counter pain relievers usually help. See your doctor if you have a high fever, breathlessness, symptoms lasting more than three weeks, or you have a long-term condition such as COPD or a weakened immune system.

Are e-cigarettes a good way to quit smoking?

E-cigarettes are not FDA-approved quit aids, and their long-term effects on the lungs are still being studied. The approved options, nicotine replacement, varenicline and bupropion, combined with counseling, are the best-supported approach. If you do switch to e-cigarettes, aim to stop smoking completely rather than using both. Call 1-800-QUIT-NOW for free help making a quit plan.

What should I do on days when air quality is poor?

Check the Air Quality Index at AirNow. When it is above 100, people with lung or heart disease, children, older adults and people active outdoors should cut back on strenuous outdoor activity. Stay indoors with windows closed during heavy wildfire smoke, consider a HEPA air cleaner, keep your medicines nearby, and follow your action plan if symptoms worsen.

Should I test my home for radon?

Yes. Radon is an invisible, odorless gas that is the second leading cause of lung cancer in the US and the leading cause among people who have never smoked. Any home can have high levels, whatever its age or location. Test kits are inexpensive. The EPA recommends fixing your home if the level is 4 pCi/L or more, which can usually be done.

Is it safe to use asthma inhalers during pregnancy?

Keep taking your asthma medicines as prescribed and do not stop them on your own. Poorly controlled asthma poses more risk to you and your baby than the medicines commonly used to treat it. Tell your doctor you are pregnant so your treatment and action plan can be reviewed, and get urgent care for any asthma attack during pregnancy.

When to speak to a doctor

See your doctor for a cough lasting more than three weeks, new or worsening breathlessness, wheezing, needing your rescue inhaler more than two days a week, waking at night with symptoms, or a change in the color or amount of mucus with COPD. Coughing up blood always needs prompt assessment. Get same-day care for fever with breathlessness, new confusion in an older adult, or breathlessness with one-sided calf pain or swelling. Call 911 if a rescue inhaler is not helping, for severe breathlessness or inability to speak in full sentences, blue or gray lips or fingernails, chest pain, a child who is struggling to breathe, grunting or limp, or suspected carbon monoxide poisoning. For questions about a chemical or fume exposure, call Poison Control at 1-800-222-1222.

Where this comes from

• National Heart, Lung, and Blood Institute — 2020 Focused Updates to the Asthma Management Guidelines
• National Heart, Lung, and Blood Institute — COPD
• US Preventive Services Task Force — Lung Cancer: Screening
• US Preventive Services Task Force — Tobacco Smoking Cessation in Adults, Including Pregnant Persons: Interventions
• CDC — How to Quit Smoking
• CDC — Chest Cold (Acute Bronchitis)
• CDC — Pneumococcal Vaccine Recommendations
• CDC — Who Needs a Flu Vaccine
• AirNow — Air Quality Index (AQI) Basics
• EPA — A Citizen's Guide to Radon

How this page was put together

Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.