Breathing myths

Beware of false knowledge; it is more dangerous than ignorance.
George Bernard Shaw, Irish playwright, 1856-1950

These are the common breathing myths (about ‘good breathing’) that do the rounds.

Myth 1:       Deep breathing is good for you
Myth 2:       The more oxygen we take in, the better
Myth 3:       Carbon dioxide is a poisonous waste gas
Myth 4:       Most people need to breathe more

Myth Busting

 Myth 1: Deep breathing is good for you

It is a myth that ‘deep’ breathing, that is, meaning ‘big, large-volume’ breathing as it usually does, is good for you. This belief may well qualify as public health enemy number one! The three big flaws in the advice to breathe deeply are that people tend to increase their breath size far above normal, dump out too much carbon dioxide and worst of all, believe that it is good for them to do so. This is a recipe for hypoxia – reduced oxygen in your cells. (When carbon dioxide drops too far, blood vessels narrow and restrict blood flow to vital organs and oxygen uptake by your cells goes down (Bohr effect).

The truth then is that the more you breathe, the lower the oxygen level in your brain and body tissues. This is why you can get dizzy/hypoxic blowing up balloons and practising deep breathing in a fitness class. Is it any wonder there are so many bad breathers and so much breathing-related illness in the western world today, where deep breathing is so widely promoted as a health practice. Using the diaphragm to breathe is good – but you have to get the volume right!   Remember – deep breathing is NOT good for you.

Myth 2:   The more oxygen we take in, the better

We normally breathe in far more oxygen than we need or can use. With normal breathing, a healthy person’s blood is already 97-99% saturated with oxygen. People with healthy lungs can in fact lower their breathing rate quite a lot, or breathe air that is lower in oxygen (like at altitude) for quite a while before they notice any difference. A study published in the New England Journal of Medicine in January 20091 in which researchers sampled blood oxygen levels in themselves and other climbers just below the summit of Mt Everest, showed oxygen levels that were previously thought to be incompatible with life yet these people were moving around and talking fluently.2 One researcher’s blood oxygen was less than half that which would normally result in admission to intensive care. These findings suggest that the lack of oxygen is less critical than the body’s ability to deliver and efficiently use the oxygen – which is dependant on heart function and carbon dioxide levels amongst other factors. This also ties in with findings that giving oxygen and aggressively ventilating patients in some critical health care situations may have harmful outcomes, and that CPR (cardiopulmonary resuscitation) guidelines overestimated the need for ventilation by two to four fold. First aid courses now teach a heart compression to breaths given ratio of 30:2 rather than the previous CPR standard of 15:2, and an even earlier one of 5:2.

Myth 3:   Carbon dioxide is a poisonous waste gas

There is another common instruction: “Take deep breaths and blow off your ‘stale’ carbon dioxide”. We may be exhorted to fully and forcefully exhale, to expel more of this ‘poison’. Carbon dioxide is in fact a clear, tasteless, odourless gas that is absolutely necessary to sustain life. It is a vital part of all organic life on this planet. Like oxygen, we need the right amount – too much or too little is a problem. If carbon dioxide drops too low it is fatal. The body has built in protective mechanisms to prevent this, (sleep) apnoea being one of them.

In the atmosphere, even with man-induced ‘global warming’, carbon dioxide still remains a trace gas at just 0.038% of the atmospheric gases. Healthy people maintain a level between 5.5 and 6.5% in their lungs. CPR again provides an example – many people have been successfully resuscitated using the rescuer’s expired air. If what came out of our lungs was so poisonous how could CPR save lives? There have also been several studies done by emergency medicine professionals showing that the cardiac arrest patients with the lowest lung carbon dioxide levels had the least chance of survival.

Myth 4: Most people need to breathe more

False again. Research shows ‘normal’ – relatively healthy – people are now breathing significantly more air per minute (minute volume) than in previous generations.  The average adult in the 21st Century is breathing around 12L/minute when the physiological norm is 5L/minute. (Why? The short answer – stress increases breathing.)  Even higher minute volumes are characteristic of many lifestyle diseases.

A better belief system

Just because the bulk of the population believe something does not make it fact! Popular beliefs are often based on blind faith or ideology (or even profit) rather than robust science. History is littered with examples of beliefs taken as fact that have been proven to be fiction. Just think flat earth and the sun revolving around the earth. Other cultures place more emphasis on correct breathing than western culture does. Healers in the Hindu, Buddhist, Native American and Hawaiian traditions connect many illnesses with incorrect breathing. How different from the western world’s ‘deep breathing’ mantra are the words of the Chinese philosopher, Lao Tzu (circa 400BC) “The perfect man breathes as if he is not breathing ”


Don’t worry – its quite doable to change the way you breathe for the better, through breathing retraining . First you get informed, then undo the faulty habits you have and then replace them step-by-step with silent, efficient, gentle and comfortable breathing.

Better health – for every breath you take

1. Grocott, PM, Martin, DS, Levett, DZH, McMorrow, R, Windsor, J, Montgomery, HE, (2009).Arterial Blood Gases and Oxygen Content in Climbers on Mount Everest. NEJM 360:140-149
2.Laurence, Jeremy, Health Editor. “The doctor who dropped his trousers on top of the world” The Independent; Thursday 8th January 2009.



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