Asthma vs COPD: How They Differ in Smokers
Key takeaways
Asthma and COPD both make breathing harder and share symptoms such as cough and shortness of breath. Canadian sources describe asthma as a life-long condition that people can manage with treatment, and COPD as a disease with no cure where smoking is the leading cause.
Many people who smoke ask whether a wheeze or a lingering cough points to asthma or to COPD. The two conditions overlap in how they feel, which is why the differences in cause, course and testing are worth laying out. The Canadian sources below describe each one in its own terms, and they do not always address the same questions, so some rows in the table are shorter than others.
Side-by-side comparison
| Asthma | COPD | |
|---|---|---|
| What it is | A chronic (life-long) condition that makes it harder to breathe (Lung Health Foundation) | A chronic disease characterized by shortness of breath, cough and sputum production (PHAC) |
| Typical symptoms | Coughing, shortness of breath, chest tightness and wheezing (PHAC) | Shortness of breath, a long-lasting cough and wheezing (Lung Health Foundation, PHAC) |
| Main causes and risk factors | Family history of allergy and allergic disorders, and exposure to tobacco smoke, including before birth (PHAC) | Smoking, described as the number one cause (Lung Health Foundation, Health Canada) |
| Can it be cured? | Cannot be cured, and for some people it goes away (Lung Health Foundation) | No cure (Health Canada) |
| Testing | Spirometry is the most common lung function test (Lung Health Foundation) | Spirometry is called the gold standard way to diagnose it (Lung Health Foundation) |
Causes and the role of smoking
The Public Health Agency of Canada says cigarette smoking is the principal underlying cause of COPD. The Lung Health Foundation uses nearly the same wording and calls smoking the number one cause. Health Canada adds that quitting smoking is the single most effective intervention for COPD.
Asthma has a different pattern. The Lung Health Foundation notes that asthma and allergies often run in families, and that each person has their own set of triggers. PHAC lists a family history of allergy and exposure to tobacco smoke, including before birth, as risk factors. Smoking is therefore tied to both conditions in these sources, but it is named as the leading cause only for COPD.
Symptoms that overlap
Cough, shortness of breath and wheezing show up in both lists. That overlap is the reason a symptom alone cannot tell you which condition you have. For a closer look at the COPD side, see COPD symptoms. If you have had a cough for weeks or months, the Lung Health Foundation lists a cough lasting three months or more among COPD symptoms, and it is worth raising with a doctor.
Can either one be reversed?
The sources use careful language here. The Lung Health Foundation says asthma cannot be cured, adds that for some people it goes away and never comes back, and says that with proper treatment people with asthma can lead active lives. Health Canada says there is no cure for COPD, and describes emphysema, one form of COPD, as gradual and irreversible damage of lung tissue. See emphysema and chronic bronchitis for those two forms, and COPD stages and smoking for how the disease is staged.
How doctors tell them apart
The Lung Health Foundation calls spirometry the gold standard way to diagnose COPD and the most common lung function test. Spirometry measures how well your lungs are working. The sources we read do not lay out the specific results that separate one condition from the other, so that decision is left to your doctor. If you are curious what smoking does to lung tissue more broadly, smokers’ lungs covers it, and the lung diseases overview places both conditions among the others.
Having both
The Lung Health Foundation says asthma may be a risk factor for the development of COPD. None of the pages we read states how many people have both conditions at once, so we do not give a figure.
What to do next
If you smoke and notice breathlessness, wheezing or a lasting cough, speak to a doctor or pharmacist, or call 811 where it is available for health advice. This page is general information from the sources listed, not personal medical advice.
What we could not confirm
- How common it is to have asthma and COPD together.
- Specific spirometry results that separate asthma from COPD.
- How much asthma raises the later risk of COPD.
- A comparison of the two conditions on HealthLinkBC, whose page content we could not read in full.
Health information is general and educational. It does not replace advice from a doctor, pharmacist or nurse. Read the full disclaimer.
Frequently asked questions
Is COPD the same as asthma?
No. Canadian health sources describe them as separate conditions with different main causes. The Lung Health Foundation says smoking is the number one cause of COPD, while asthma is linked to family history, allergies and triggers that differ from person to person.
Can asthma turn into COPD?
The Lung Health Foundation says asthma may be a risk factor for developing COPD. It does not say asthma becomes COPD, and it does not give a number for the risk.
Which one can be cured?
The Lung Health Foundation says asthma cannot be cured, although for some people it goes away. Health Canada says there is no cure for COPD. Treatment is the focus for both.
How do doctors check for each one?
The Lung Health Foundation calls spirometry the gold standard way to diagnose COPD and the most common lung function test for asthma. A doctor decides which tests you need.
Sources
- Asthma — Lung Health Foundation. Accessed November 13, 2026.
- COPD — Lung Health Foundation. Accessed November 13, 2026.
- Asthma — Public Health Agency of Canada. Accessed November 13, 2026.
- Chronic obstructive pulmonary disease (COPD) — Public Health Agency of Canada. Accessed November 13, 2026.
- Tobacco and chronic obstructive pulmonary disease — Health Canada. Accessed November 13, 2026.