Introduction

What is asthma?

Asthma is a chronic condition where the airways in the lungs become narrowed and inflamed, resulting in difficulty breathing. The airways are tubes that allow and carry air in and out of the lungs, but due to their restriction in asthma, this process becomes difficult.

Asthma can affect any individual of any age, but tends to start in childhood. Certain factors can trigger or worsen asthma symptoms. Some may include:

• Pollen
• Exercise
• Viral infections
• Cold air

Asthma is a condition that can be managed through a treatment and management plan but, unfortunately, there is no cure.¹

Symptoms

Asthma can be characterised by:

•  Wheezing
• Shortness of breath
•  Coughing
• Tight feeling in the chest

Symptoms can come and go, and their severity can change. They are usually experienced at night or early morning, but they can happen at any time.²

Wheezing in asthma

 Wheezing, a common symptom of asthma, is a high-pitched sound due to narrowed or restricted airways and is commonly experienced in asthma patients. However, it may not be present in all cases, but its absence does not disregard diagnosis.³

Understanding exercise and asthma

Exercise-induced asthma 

Exercise-induced bronchoconstriction (EIB) is a temporary narrowing of the airways, and it happens due to exercise and physical activity. While exercising, an increase in airflow occurs, which requires the airways to warm and humidify large amounts of air coming in. This warmth and humidification cause the restriction of the airways, potentially triggering symptoms. In some people, this can lead to inflammatory, vascular and neuronal responses, causing bronchial smooth muscle contraction.⁴ This is where smooth muscle around the airway in the lungs tightens, decreasing its diameter and causing the onset of symptoms. 

Distinction between EIB and chronic asthma 

Although EIB and chronic asthma share the same symptoms, shortness of breath and coughing, they have different causes. 

EIB is a narrowing of the airways that is temporary, resulting from intense exercise or activity and can last for up to fifteen minutes after the activity. Moreover, it causes asthma and triggers symptoms which are exercise-induced.⁷ This is the main trigger but can also respond due to other irritants like dust, pollution, and cold or dry air while exercising. 

Whereas, chronic asthma is a long-term condition of inflammation and narrowing of the airways usually triggered by allergens, like animal dander, pollen, dust, smoke and perfume. There can also be many other irritants and allergens. 

Both EIB and chronic asthma tend to have very similar symptoms of breathlessness, tight chest, coughing, and wheezing. However, EIB can also result in reduced energy levels and stamina as it is exercise-related, whereas chronic asthma is due to a reaction to allergens.⁶

Misconceptions about exercise in asthma patients 

There are some misconceptions about exercising in asthma patients. 

One of these is that exercising does not cause asthma, but triggers its symptoms. 

Another is that if you have asthma, it does not make you allergic to exercise. Again, the triggers of the condition such as weather and environment conditions, allergens and irritants ,contribute to the narrowing of the airway whilst exercising but does not mean that it makes exercising impossible for you. 

Finally, managing EIB does not always need specialised help. If you treat the asthma properly, it will treat the triggering in exercise.⁷ This may involve getting specialist advice or visiting your GP, but you can also monitor yourself. This may be using an inhaler, nebuliser to relieve symptoms, taking medications like short or long-acting beta-agonists, corticosteroids (which reduce airway swelling to help increase airflow) and mast cell stabilisers to reduce airway inflammation.⁸

Benefits of exercise for asthma patients

Exercising in asthma patients can help to improve symptoms, lung function and quality of life significantly.⁹

Respiratory muscle training and aerobic exercise combination can improve respiratory muscle strength and endurance, which can help patients, especially those with severe asthma, to breathe better whilst exercising and improve oxygen utilisation.^10,11

Moderate aerobic activity, high-intensity interval training and breathing exercises have been seen to benefit asthma patients. Moderate exercise training has been shown to reduce inflammation, EIB and bronchial hyperresponsiveness. There are benefits to asthma symptoms, medication use, anxiety and depression related symptoms, lung function, exercise capacity and sleep quality. 

Overall, exercise improves clinical condition, quality of life and airway inflammation.¹² Aerobic and breathing exercises are commonly used; however, high-intensity interval training has shown great results too.¹³

Safe exercise practices for asthma patients 

Pre-exercise 

• Managing symptoms: working with your healthcare provider to manage symptoms before starting an exercise program is important. Follow instructions on taking asthma medications, e.g. reliever inhaler
• Perform a gentle warm-up before starting any exercise routine. This should be related to age and health status, so it is good to check with your provider for confirmation
• Check weather and environmental conditions to avoid triggers and allergens, e.g if pollen levels are high, it is best to stay indoors
• Use a cover for your mouth and nose to protect the airways from cold and dry air¹⁴

Choice of exercise

Certain activities and sports are better than others.

Swimming is often a good choice because it's done in a warm and humid environment. However, if your asthma makes you sensitive to chlorine, it would be better to pick a different activity, e.g. baseball or golf (activities with a short burst of activity/exercise).

Other activities to try include yoga, walking, hiking, and leisure biking.¹⁵

Monitoring symptoms

Watching, monitoring and even keeping a record of symptoms is great when exercising. This can help you see when, where and how often you are experiencing symptoms and when you may feel overexhausted to your normal or less severe symptoms.

Using a peak flow meter is a helpful hand tool to monitor your asthma, as it measures how fast an individual blows air out. An individual with asthma or narrowed/inflamed airways, the peak flow (measurement) will be low. A very low measurement may indicate need of extra medicine or needing to rest during exercise.

Working with or asking a healthcare provider for any support, advice or plan is beneficial. It can also help in scenarios, like at school recess or other activities, where there may be confusion on whether an individual with asthma can partake in an activity, as it may be too demanding.¹⁶

When exercise may be contraindicated

Despite exercise being a positive factor and support for symptomatic individuals, it is important to remember that there can be times when resting is better. You should not exert stern pressure to continue exercising if symptoms are worsening, as the aim of exercising is to relieve symptoms and allow you to maintain the normality of still being able to exercise in everyday life. However, as exercise can cause inflammation to the airways, it is important to listen to your body and symptoms and rest when needed.

Also, in the state of acute exacerbations, which is the sudden onset and progression of asthma symptoms, exercise can be contraindicated. This is also known as a ‘flare-up’. The inflamed airways cause an increased production of mucus (phlegm), which is a sticky substance, making it difficult to cough up and worsening the symptoms.

Also, other causes are viral or respiratory infections. Again, this is due to inflammation and narrowing of the airways. Moreover, exercising on top of this can cause further stress to the airways.¹⁷

Exercising is not to exacerbate or worsen conditions but to help as a management and support. Overall, it is crucial to keep your healthcare provider in the loop to understand your asthma and have a management plan and understanding in place. You do not want to make symptoms worse and suffer complications like an asthma attack.

Summary

To conclude, asthma is a respiratory condition involving inflammation and restriction of the airways, caused by certain allergens and irritants, resulting in difficulty in breathing and possible wheezing. When this becomes long-term, it is known as ‘chronic asthma’. EIB, on the other hand, is an exercise-induced type of asthma – a temporary reaction to exercise, especially severe exercise. However, the conditions, environment and irritants play a role towards this flare-up. 

Exercising moderately and creating a management plan with your healthcare provider is still very important to help relieve asthma symptoms, as exercising helps to strengthen respiratory muscles, and more so over time. These strengthened muscles help to improve breathing, allowing better and smoother airflow. Despite the benefits and importance of exercise, it is vital not to exhaust the body with excessive physical activity. 

Furthermore, if you experience your asthma symptoms worsening or a sudden onset and progression of symptoms arise, or if you have a viral or respiratory infection or other health condition, it is better to rest and not exercise. You do not want to worsen symptoms and experience complications like an asthma attack.