Asthma affects people all over the world and of all ages – in Canada, it is the third-most common chronic disease. It affects more than 3.8 million people. Tragically, 317 Canadians are diagnosed with asthma every day, and every week roughly 4 Canadians die from an asthma attack. But, with proper asthma management, people can live healthy and active lives.

What is Asthma?

Asthma is a chronic, long-term disease of the airways, the tubes that carry air into our lungs. It causes inflammation and narrowing of the bronchial tubes that leads to airflow limitation.

The airways of our lungs are surrounded by muscles and contain mucus glands. These muscles are normally relaxed but if you have asthma, they are often sensitive and inflamed.

When people with asthma encounter triggers, these muscles react by tightening even more, the lining of the airways swell and the airways can fill up with mucus. This makes breathing very difficult and leads to asthma symptoms or an asthma attack.

Asthma is caused by two types of triggers (a trigger is anything that irritates your airways):

  • Allergic, caused by inflammatory triggers such as dust mites, pollens, moulds, pet dander, viral infections
  • Non-allergic, triggered by smoke, exercise, cold air, certain air pollutants, intense emotions

Asthma Symptoms

Asthma can be different for everyone. Asthma symptoms can also vary over time, with few or no symptoms when asthma is well-controlled. The most common symptoms include:

Regular coughing often occurs at night or early in the morning, although it can happen at any time of day. Coughing is a major feature of asthma, especially in children. Sometimes, persistent coughing can be the only sign of asthma.
    Wheezing is a breathing with difficulty and with a whistling sound coming from your airways.
  Shortness of breath gives you the feeling that you cannot breathe well enough. You may even find it difficult to eat, sleep or speak.
    Chest tightness is an unpleasant feeling of heaviness or pressure in the chest. It can make breathing more difficult.
    Increased mucous production is characterized by high levels of a thick fluid accumulated in your airways.


These symptoms can occur slowly over hours or days, or they can come on as sudden, recurring attacks after which the symptoms can persist for some time before disappearing. If left untreated, asthma can cause permanent structural changes in your airways called – “airway remodelling,” – which is why it is important to get asthma under control and keep treating it over the long term.

What Causes Asthma?

Nobody can say for sure what causes asthma. However, researchers have determined that the following risk factors can lead to asthma development:

  • Family history/genetics: Children of mothers with asthma are 3 times more likely to suffer from asthma, and 2.5 times more likely if the father has asthma. More than 30 genes have been linked to asthma so far, and gene-gene interactions, gene-environment interactions and epigenetic modifications also play a part. Genetic differences also play a role in differences in response to treatment.
  • Allergies: People are more likely to have asthma if they have certain types of allergies, such ones which can affect the eyes and nose. However, not everyone who has allergies will get asthma and not everyone who has asthma is affected by allergies. Respiratory allergies as well as some types of asthma are related to an antibody called immunoglobulin E (IgE), which the immune system produces in response to allergens. To protect the body, the IgE causes allergic reactions that can affect the eyes, nose, throat, lungs and skin.
  • Premature birth: Children born before 37 weeks are at increased risk of developing asthma later.
  • Lung infections: Babies or little children may be at risk of developing asthma later if they had certain lung infections at a very early age.
  • Occupational exposures: There are more than 200 substances including gases, dust particles and chemical fumes and vapours that can cause asthma in the workplace. This type of asthma known as occupational asthma is a common cause of adult onset asthma.
  • Hormones: Some women can develop adult onset asthma during or after menopause.
  • Environment: Smoking, exhaust fumes and airborne particulate matter can be linked to causing asthma.
  • Obesity: Extra weight around the chest might squeeze the lungs and make it more difficult to inhale. Fat tissue produces inflammatory substances that might influence the lungs and affect asthma.

Diagnosis and Lung Tests 

Symptoms observed upon physical exam, medical, and family history may support a diagnosis of asthma. Other lung conditions have similar symptoms, which your healthcare practitioner may have to rule out. It is important to explain all of your concerns and to ask any questions you may have. Something you think is not important may be useful in pinpointing the problem.

Only a healthcare provider can diagnose asthma. Conditions such as pneumonia, cystic fibrosis, heart disease, and chronic obstructive pulmonary disease (COPD) have to be ruled out before your doctor can be certain that you have asthma.

To confirm the diagnosis, your healthcare provider may ask you to do breathing tests. They check how well your lungs perform and how asthma affects your breathing. These lung function tests include spirometry breathing tests and peak flow breathing tests.

What is spirometry?

Spirometry is a type of pulmonary function test (PFT) used to diagnose lung conditions like asthma and COPD. A spirometer measures the amount of air you can breathe out in one second and the total volume of air you can exhale in one forced breath.

How is a spirometry test performed?

  1. You will sit upright
  2. You will be given a clip to place on your nose
  3. You will be given a plastic mouthpiece connected to a spirometer
  4. You will place the mouthpiece in your mouth and create a tight seal with your lips
  5. You will take a deep breath in and then blow out as hard and fast as you can until you can’t blow out any more
  6. You will do the test several times, until the best result is recorded
  7. You will take some puffs of a bronchodilator medication
  8. After 15 minutes, you will do the test again, to see if the medication helps your breathing. If your results are much better after taking the medication, you may have asthma.

Your healthcare provider will explain your results.

*Infants and small children under 5 to 6 years old usually cannot do the spirometry test.

How to prepare for spirometry tests?

Your healthcare provider will give you detailed instructions prior to the test. Generally, you will be asked to refrain from using certain  inhalers for a period of time prior to the test. If you are a smoker, you will be asked to refrain from smoking for a period of time prior to the test. For support to quit smoking, visit You can quit smoking. We can help.

What is a peak flow meter?

A Peak Flow Meter estimates the Peak Expiratory Flow Rate, which is a measure of the fastest speed at which you can exhale the air from your lungs, after inhaling a big breath. The measurement relates to how well the air is moving through your airways, so if asthma is present with airway inflammation or bronchoconstriction, the peak flow levels will be lower. Three peak flows are measured in succession and the best reading is recorded.

Using the Asthma Monitor for these measurements allows you to monitor your asthma on a day to day basis and will help determine the effectiveness of prescribed anti-inflammatory (controller) medications.

If you are diagnosed with asthma, a healthcare practitioner will

Create a customized treatment plan known as an Asthma Action Plan that fits your particular needs, lifestyle and triggers, as well as  the frequency and intensity of your symptoms.
If necessary, refer you to other healthcare professionals – individuals who can help you with specific aspects of asthma treatment and  management.
   Prescribe you asthma medicines to minimize your symptoms.
   Recommend that you visit regularly so that your symptoms can be monitored and your treatment adjusted if necessary.

Preparing for Your Appointment

You can get the most out of your time with your healthcare provider by planning carefully before you go.

Things you can do to prepare for your appointments include bringing:

  • A list of your most recent symptoms, including notes about whether they’ve changed since your last visit
  • A record of your recent peak flow meter readings or symptom diary records
  • Your Asthma Action Plan so that you and your doctor can develop a plan. If you already have one, then bring it in case it needs to be modified
  • Your inhaler(s) to review your technique
  • A list of any questions you have, e.g. What makes my asthma worse? Is it okay to keep playing a sport? What should I do if I have an asthma attack?

Can Asthma Be Cured?

Despite advances in understanding the disease, and the availability of more efficacious medications, asthma is still a major cause of morbidity. This is often a result of under-diagnosis, under-treatment, lack of public understanding and knowledge about the disease, and inadequate asthma supervision.

There is still much research that needs to be done to fully understand how to prevent, treat and cure asthma. Even though most people with asthma do not die as a result of the disease, they may spend part of their daily lives coping with the symptoms. But, with proper management, people with asthma can live healthy and active lives.

Have Questions?

If you have questions and think that you may have asthma, you can contact our free Asthma & Allergy HelpLine call-back service. Email or call 1-866-787-4050 to be connected with a Certified Respiratory Educator who can provide you with personalized support.

*Please note that we are currently experiencing a greater volume of calls due to COVID-19, so you may experience longer than normal wait times for a response.

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The Asthma Canada team, including our Certified Respiratory Educators work tirelessly to provide our community with the very latest, evidence-based asthma education and support services.

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