The physiological cause of asthma is a lack of air getting into and out of the lungs due to triggers that cause an inflammation in the airways, a build up of mucus in the airways, or a contraction in the smooth muscle in the airways. The typical symptoms of asthma include; shortness of breath, tightness in the chest, and wheezing
Who has asthma?
In 2005 the World Health Organization (WHO) estimated that 1 billion people globally suffered from chronic respiratory diseases (CRD), of which asthma was the most prevalent. The WHO estimated that 300 million people globally had asthma in 2005 and this number is increasing. In relatively wealthy countries (USA, Canada, UK, Australia, New Zealand) it is estimated that 1 in 5/6 people suffer from asthma.
The 'exact' cause of asthma is still unknown, however there is significant information gathered about what triggers this condition and its symptoms. Factors which are currently being investigated and studied in relation to the cause of asthma include: “diet, climate, pollution, immunisation rates, economic condition, community health care standards, antibiotic use early in childhood, and the timing and number of respiratory infections in early life”.
What is asthma?
When we take a breath in (inhale or inspire), the air travels down hollow tubes to reach the lungs and then back out these tubes to be exhaled or expired. These tubes are the trachea, bronchi and bronchioles, as seen in this image
In individuals who have asthma, these tubes become narrower. The individual may feel that they have trouble getting air into the lungs and the natural response is to try and inhale harder. The problem is in fact, with getting the air out of the lungs.
What causes the airways to become narrower?
The following three factors cause the airways of people with asthma to narrow:
1. Inflammation – the lining of the airways becomes swollen inside reducing the area available for air to travel
2. Mucus – the lining of the airways produces excess thick, sticky mucus which obstructs the airways
3. Muscle contraction – involuntary muscles surrounding the airways contract which also reduces the area available for air to travel
Why do the airways become narrower?
Airways become narrower due to various triggers. The triggers can be allergens, illness, environmental factors (cigarette smoke) and emotional factors (anxiety). Some examples are listed below.
- Colds and flu
- Cigarette smoke and air pollution – irritates the lining of the airways
- Exercise - exercise induced asthma (EIA) is thought to be caused by the cool air which is breathed in while exercising, causing the lining of the airways to become dry and resulting in the airways tightening
- Cats and other pets
- Allergies to house dust mites (found in carpets and bedding), pollen and some foods
- Weather changes
- Some plants
- Strong emotions such as anxiety
Symptoms of asthma:
The major symptoms of asthma are:
1. Shortness of breath – Airways narrow when triggered. An example could be if a person ran up some stairs without warming up. This could trigger the airways to narrow just when more oxygen is needed causing the individual to feel short of breath.
2. Tightness in the chest – this is a heavy, tight feeling in or across the chest. It can often be an indication that stale air is trapped in the chest, unable to escape due to the narrowing of the airways.
3. Coughing – this is a mechanism of getting rid of unwanted or foreign material from the lungs e.g. mucus. In asthmatics, coughing can be a reflex reaction to the inflammation and obstruction in the airways, this type of cough does not produce any mucus and is not particularly helpful as the airways are blocked due to inflammation and tight muscles, not an object that can be removed through coughing.
4. Wheezing – if the airways are narrowed, when air is expelled it can make a whistling or wheezing sound. Wheezing is one of the typical symptoms of asthma that differentiates a person suffering from asthma from a person suffering from heart disease.
5. Feeling tired – a lack of oxygen and increase in carbon dioxide levels can cause the individual to feel tired.
There is no apparent cure for asthma but various types of medication can be used to treat it. Most of these treatments work by helping to stop the breathing tubes from overreacting to triggers and narrowing. The medication can come in a number of forms such as inhalers (most common), tablets or liquid form.
The 2 main types of medication for asthma are:
- Anti-inflammatory drugs - This is the most important type of therapy for most people with asthma because these drugs prevent asthma attacks on an ongoing basis. Steroids, also called "corticosteroids," are an important type of anti-inflammatory medication for people suffering from asthma. These drugs reduce swelling and mucus production in the airways. As a result, airways are less sensitive and less likely to react to triggers.
- Bronchodilators - These medications relieve the symptoms of asthma by relaxing the muscle bands that tighten around the airways. This action rapidly opens the airways, letting more air come in and out of the lungs. As a result, breathing improves. Bronchodilators also help clear mucus from the lungs. As the airways open, the mucus moves more freely and can be coughed out more easily.
The medication can be used in the following 3 ways:
- Preventers - are inhalers that are taken daily by the individual and help to prevent the airways from narrowing and assists with making the tubes less irritable. These inhalers are usually brown, dark red or orange
- Relievers - treat and relieve the symptoms by encouraging the muscles surrounding the airways to relax if a specific trigger causes a reaction or tightening of the airways. These inhalers are usually blue
- Symptom-controller - these are taken twice a day to encourage the muscles surrounding the airways to remain relaxed. It is known as a long-acting reliever as it lasts for approximately 12 hours. These inhalers are typically green.
Some children do grow out of asthma by the time they are teenagers. If asthma develops in an adult it tends to remain. One big influence on the severity of asthma is smoking as it irritates the airways causing them to narrow.
What to do during an asthma attack?
Be prepared! When you conduct your consultation with new clients you should find out whether they have asthma or not. If your client is asthmatic then you’ll need to ensure they always bring their inhaler with them to training sessions. When a client coughs and wheezes due to asthma then give them their reliever medication two to three times over a few minutes. If this does not control the symptoms, take them to the doctor or to a hospital emergency department.
Call an ambulance in an emergency
Don’t delay - call an ambulance immediately when your client:
- Finds it very difficult to breathe.
- Is unable to talk or is turning blue.
- While waiting for the ambulance, you should hand your client their reliever medication every one to two minutes.
Ways to keep asthma under control
Here are some ways you can help your clients to keep their asthma under control;
- work out what triggers asthma and avoid those triggers – this may include not exercising outdoors on cold mornings or during ‘rush hours’ when traffic is heavy and the air is polluted
- get to know your clients symptoms and don’t ignore them
- encourage the use of a peak flow meter (an apparatus to measure how fast you can blow air out) to monitor symptoms and medicate appropriately
- understand how asthma medicines work and take your preventer medicine daily and at regular times
- help clients that smoke to give up or reduce their smoking
Asthma should not discourage an individual from exercising. They will just need to be vigilant in monitoring and responding to their own signs and symptoms.
It is recommended people with asthma exercise in a warm moist environment, especially if they have EIA. EIA is often referred to as exercise induced bronchospasm and occurs due to cold or dry air irritating the airways. As air is taken in more quickly during exercise than normal, the body doesn’t have time to warm the air before it reaches the airways triggering asthma.
To avoid EIA it is important that a full warm up is undertaken and that the individual has their medication handy e.g. their reliever. If EIA occurs, then encourage the individual to breathe through their nose (warming the air) and to relax to let the air flow out slowly.