Asthma

InhalerPerhaps you’ve noticed that diseases like asthma are on the increase. One in ten Australians has asthma, and the national medical bill is between $600 million and $700 million a year. Around one in three asthmatics say that their asthma interferes with the quality of their lives. In addition, around 400 people a year die from this condition in Australia every year. So why is it on the increase? And what can be done about it? You’ve come to the right place to find answers to your questions.

How Asthma Is Diagnosed

Asthma is a condition in which the airways become hyper-responsive – causing them to narrow and obstruct. This happens in episodes and is reversible. In fact, the way asthma is diagnosed is through a lung function test that helps determine the degree of obstruction, and whether a broncho-dilator like Ventolin reverses the narrowing. If this is the case, then asthma is typically diagnosed. While lung function tests are very useful in determining the diagnosis and the degree of obstruction in the case of asthma, what most people do not know is that asthma is invariably accompanied by two other abnormal physiological values – values that are rarely measured: An image of an asthma-inflamed bronchial tube on a white background

 

  1. The level of carbon dioxide in the lungs (called alveolar CO2)
  2. The amount of air a person breathes (called minute volume)

Alveolar CO2 Level

Alveolar CO2 is the amount of carbon dioxide that is left in the alveoli sacks in the lungs after exhaling. Carbon dioxide is not just a ‘waste gas’ as most people suppose – it is in fact an important substance that acts much like a hormone in the human body. Because it is required for important bodily processes it needs to stay within certain parameters. CO2 levels in healthy adults is usually in the range of 4.7% to 6.0%. However the average CO2 level in mild asthmatics has consistently been found in clinical trials to be significantly lower than this – in the range of 3.7% to 4.4%.

Alveoli in lungs - blood saturating by oxygen
Alveoli in lungs – blood saturating by oxygen

Minute Volume

This is a fancy term for the amount of air that a person breathes in and out in the course of one minute. Minute volume for healthy people lies in the range of 5 to 7 litres. In other words, healthy people inhale and exhale between 5 and 7 litres of air a minute. A person breathing 12 times a minute, and with a normal breath size of half a litre will have a minute volume of 6 L/min (12 breaths x 0.5 L= 6 L). However, asthmatics have been found in multiple research studies to breathe on average 14 litres a minute, over twice this amount. This is easy to do and hard to detect. For example, a breathing rate of 20 per minute, and a breath size of 700 ml gives a minute volume of 14 L/min (20 breaths x 0.7 L = 14 L). Breathing more than is required is called hyperventilation, or over-breathing.

 

Over-Breathing

The reason this ‘over-breathing’ is easy to do and hard to detect is because air is invisible and almost weightless. It is over-breathing that causes the lowered level of carbon dioxide in the lungs, and hence in the blood. This is because the carbon dioxide level in the air is only 0.03%, whereas normal levels in the alveoli in the lungs are 5-6%. Extra breathing works towards equalising these pressures. Overtime, the breathing centre in the brain and carotid arteries adapt to a lower level of carbon dioxide. As rising carbon dioxide levels in the blood are the stimulus to breathe, this perpetuates the problem of over-breathing.

The Role of Carbon Dioxide in the Human Body

The loss of carbon dioxide has a profound effect on the physiology of the asthma sufferer. This is because a certain level of carbon dioxide is required for normal physiology. Carbon dioxide acts much like a hormone in the body. It acts to:

  • Relax smooth muscle
  • Dilate (or open) blood vessels
  • Dilate (or open) airways
  • Supress the production of histamine
  • Break the bond between oxygen and haemoglobin in the blood so that oxygen can enter cells. (This is known as the Bohr Effect – see below).

All of these actions of carbon dioxide in the human body become significant in the development of asthma. Lowered levels of carbon dioxide cause spasms of the airways – giving the sufferer the feeling of not being able to move air and out of the lungs. Lowered levels of histamine cause allergic type symptoms – so typical of what asthma sufferers experience. When oxygen bonds tightly to the haemoglobin and is not released for use by the body cells, the sufferer feels the effects of lowered oxygen, such as shortness of breath. Attempting to breathe more only exacerbates the problem, as more carbon dioxide is lost resulting in even tighter bonds between oxygen and haemoglobin. This causes progressive narrowing of the airways and can cause serious life-threatening airway constriction. This is what happens in a serious asthma attack.

Breathing Retraining

Breathing retraining works to normalise breathing – it raises the level of carbon dioxide in the lungs and blood so that the beneficial effects can be experienced: broncho-dilation (opening up the airways), suppression of histamine production (reducing mucous production and allergy-like symptoms), and normalising the release of oxygen to body cells. All of these effects work together to reduce the symptoms of asthma.

In addition, breathing retraining looks at the lifestyle factors that contribute to over-breathing, why over-breathing is on the rise, and how to make simple adjustments that will prevent the development of disordered breathing habits again.

Asthma sufferers often experience a marked improvement in their symptoms within 3-5 days of starting breathing retraining. A number of clinical trials have shown impressive results both in the short-term and long-term for asthmatics who use the Buteyko breathing re-training technique – up to 50% reduction in the use of steroid inhalers and over 90% reduction in the use of bronchodilator medication (such as Ventolin) with better symptom control.

Join the growing number of people using this method to take control over asthma through treating the cause and not just the symptoms!

 

The Bohr Effect

In 1903 a scientist by the name of Christian Bohr made an important discovery that unravelled some of the mysteries around breathing. He discovered that the level of carbon dioxide in the blood is important in allowing oxygen to be released by the haemoglobin. At higher levels of CO2 haemoglobin releases O2 more easily. This has been named the Bohr Effect. When the level of CO2 in the blood is lower, oxygen bonds more tightly to haemoglobin, causing the symptoms of lowered oxygen in body tissues. This is a suppression of the Bohr Effect.