How do environmental factors cause asthma?
Taken from the book Close Your Mouth by Patrick McKeown
Our lifestyle has a significant effect on the way we breathe. While modern living has many benefits, it is also responsible for the negative influences of processed foods, over-eating, poor exercise habits, stress, and higher temperatures in the home. Jobs in the modern economy tend to be office- or service-based, entailing very little physical activity and many hours of talking. Ironically, in an attempt to be healthier, we are also subjected to the erroneous beliefs surrounding breathing that are found in sports classes, stress counselling and western yoga – namely that ‘big breathing’ is beneficial. All these aspects of modern life encourage over-breathing – a condition that perpetuates and exacerbates symptoms of asthma, and contributes to a host of other common complaints.
Our modern Western lifestyle has a profound influence on our breathing:
IT INCREASES IT.
Throughout this book I will use a number of different terms to describe the habit of breathing too much, such as: heavy breathing, over-breathing, chronic hyperventilation, or big breathing. Essentially, they all mean the same thing – breathing too much. It is this simple habit which is the root cause of respiratory conditions like asthma, rhinitis and snoring.
What is over-breathing?
The health industry and media have made us acutely aware of the detrimental habit of over-eating; we all know the dangers of eating in excess of our body’s requirements. Doing so is likely to lead to weight gain and a number of associated health conditions.
Similarly, over-breathing means taking in a volume of air greater than you require. In most cases, people are unaware that they have developed a habit of over-breathing as the signs are often subtle or hidden, but if you suffer from asthma it is highly likely that you exhibit some of the characteristics listed below:
- Breathing through the mouth
- Audible breathing during rest
- Regular sighs
- Regular sniffing
- Irregular breathing
- Holding of the breath (apnoea)
- Taking large breaths prior to talking
- Regular yawning
- Breathing with movement of the upper chest
- Effortful breathing
- Heavy breathing at night
- Waking with a dry mouth
Normal Breathing Volume:
The number of breaths taken per minute during normal breathing should be about 10-12. The volume of each breath should be approximately 500ml. This provides a healthy volume of 5-6 litres of air per minute.
Asthma breathing volume:
A person with asthma typically takes between 15 and 20 breaths per minute. Each breath tends to be larger than normal with a volume between 700ml and 1 litre. This provides a total volume of 10-15 litres of air per minute – more than twice the normal amount of air required for a healthy individual.
For anyone with a habit of hyperventilation, heavy breathing volume does not just occur during a symptomatic period – it is chronic, meaning that it takes place every minute of every hour of every day.
People with asthma, chronic obstructive pulmonary disease (COPD) and other respiratory complaints generally breathe 2-3 times more air than required. To continue with the comparison with over-eating, this is the equivalent of eating 10 meals per day.
Why do we over-breathe?
The causes of over-breathing vary from individual to individual but are often due to environmental factors or lifestyle habits. Often, chronic hyperventilation is simply the result of a lifelong habit of breathing through the mouth. The following seven factors are more common in countries of increasing modernisation and affluence, which may help to explain why asthma and rhinitis are so prevalent in the Western world:
- Diet: Over-eating increases breathing volume due to the additional work that is required by the body to process and digest the extra food. Eating processed foods puts further pressure on the digestive system since these foods are generally acidic, thereby altering the pH of the blood. As the body strives to correct this imbalance, breathing increases in order to remove excess carbon dioxide (CO2).
- Talking: When we speak, we need to take in large breaths of air between each sentence. When we speak at length, over-breathing occurs, exacerbating asthma symptoms and putting a strain on the body. People who work in retail, telesales and teaching know all too well how tired and constricted they can feel following a day’s work.
- Stress: When we are under stress, the ‘fight or flight’ response is activated. We react the same way to modern day stresses as we did when coming face to face with a predator thousands of years ago. The difference is, when confronted by a physical danger, we had the option of fighting it or running away as fast as possible. In modern stressful situations, our breathing increases to prepare us for physical activity, but rarely do we perform the required physical exercise to burn off the adrenaline.
- Sedentary lifestyle: When we move our muscles we generate carbon dioxide, which helps to maintain body oxygenation. A lack of exercise results in lower production of CO2 and a larger breathing volume. Fifty years ago it is estimated that we performed four hours of physical exercise each day. Today, many people are lucky if they have half an hour of exercise daily.
- Big breathing: The widely-spread belief that it is beneficial to take big breaths is a major cause of over-breathing in the Western world. Stress counsellors, gym instructors, sports coaches, and media personnel who are misinformed about correct breathing volume often encourage the practice of taking deep breaths to bring more oxygen into the body. However, very often a deep breath is confused with a ‘big’ breath. A deep breath is what a baby takes naturally – a gentle, quiet inhalation using the diaphragm, as demonstrated by relaxed movements of the tummy. In contrast, a big breath is often taken in loudly through the mouth and generally involves upper chest movement, encouraging over-breathing.
- Asthma: The onset of asthma symptoms causes the airways to constrict, leading to a feeling of suffocation. In an attempt to ease this discomfort the body begins to over-breathe, resulting in an increase in breathing rate and volume. However, greater breathing volume causes greater constriction, maintaining a vicious cycle that can only be relieved with medication. The exercises in this book help to stop this cycle naturally, reducing the need for reliever medicines or steroids.
- Higher temperatures: Modern homes and workplaces are generally well-insulated but not always well ventilated. Stuffy central-heated rooms make it difficult for our bodies to regulate body temperature through the skin, therefore encouraging us to revert to the primitive method of heavier breathing.
Over-breathing and genetic predisposition
Asthma is not a modern condition – reports of asthma symptoms date back to the ancient Egyptians – although until the second half of the twentieth century, asthma and its related symptoms only appeared to affect a small percentage of the population.
Modern living has resulted in a profound change to our breathing; the incidence of self-reported asthma increased by 74% in the US between 1980 and 1996.(19) The effects of over-breathing vary from person to person depending on genetic predisposition, but anyone who is susceptible to asthma is certain to experience an increase in symptoms if they develop a habit of hyperventilation.
In simple terms: if you carry the ‘asthma gene’ and you over-breathe, you will develop asthma. On the other hand, if you carry the ‘asthma gene’ but breathe a correct volume of air, you will not develop asthma.