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Breathlessness – a problem and a solution?

Breathing is often misunderstood in sports training, which is odd given it’s something universal to all athletes. Everyone wants to maximise their oxygen uptake, but despite what many people think, funneling larger volumes of air via our mouth is not the way to do it. If you’re feeling breathless or wheezy, either during or after exercise, then you may be experiencing exercise-induced bronchoconstriction (EIB), where your upper airways tighten and restrict air flow. You may be told it’s due to fitness but if you disagree, it’s worth checking if the way you’re breathing is a factor.

Ineffective breathing affects around 1 in 10 of the general population, but is higher amongst athletes and those suffering from asthma or anxiety. The incidence of EIB in athletes ranges from 10-50% depending on the sport and intensity. At the Athens Olympics, 21% of the UK team displayed asthma symptoms. Whilst there can be underlying health issues at play, for the majority the cause is over-breathing. With the mouth open, air reaches the lungs at ambient temperature so if it’s cold it’s a shock to the system. Temperature difference, and the loss of moisture through the mouth, causes a swelling of the upper airways. Your respiratory muscles work harder, tiring them out, and your breathing suffers further.

There are three aspects to breathing that can be used to identify ineffective breathing patterns: biomechanics and biochemistry, which I’ll explore in more detail here, and psychophysiology i.e. behaviours and symptoms. When working with a Yoga Sports Coach™, we look at the biomechanics of movement and breath in each athlete, for example observing whether they nose breathe, and if the diaphragm is being used. Recent research shows that diaphragm breathers tend to score well on a functional movement screening test, showing the benefit to postural stability that good breathing can bring.

A YSS prescription is often to encourage nasal breathing on the grounds of the cleansing benefits, and effects on the nervous system. What’s not explained as much is that nitric oxide is produced in the nasal cavity during nasal breathing and when inhaled into the lungs enhances blood flow to the well-ventilated areas thereby improving oxygen delivery. It also has a dilating influence on the airways so can reduce the symptoms of EIB. An elite triathlete was able to inhibit EIB by adapting to nasal breathing during exercise.

Whilst nose breathing at rest is well accepted by athletes, the approaches of exercising and sleeping with a closed mouth are more controversial. My interest in this approach began with reading John Douillard’s book Body, Mind and Sport (2001), and I began nasal breathing during easy and up-to-threshold runs during my training. Whilst my performance dipped initially, and I found myself needing to slow down, with practice it became comfortable and I was able to run faster at a lower heart rate. For recreational runners, nasal breathing can be successful for improving health, without sacrificing performance, as long as the athlete accepts a period of adaptation.

The scientific view on nasal breathing in elite sports is divided. Anecdotally, there are many cases of successful implementation of nose breathing at all levels of workload. Improved running economy and VO2 max have been recorded for exercise at lower intensities. However at maximal aerobic workload, one study showed a reduced VO2 max with nose breathing and another concluding that for higher intensity exercise, mouth breathing could be more efficient. Amongst athletes and coaches it’s the ultimate ‘marmite’ factor – you either love it or hate it!

Similarly, taping the mouth shut at night has its fans and critics. Nocturnal mouth breathing and sleep apnea are relatively common among athletes and can stress your body overnight when it should be a time for recovery. Considering you are asleep for around 8 hours a night, ensuring nose breathing for at least a third of your 24 hour day, is more productive than focusing just on the time you are training. It’s recommended that all suspected mouth breathers tape their mouth closed at night. This could be you if you wake up with a dry mouth and have sleepy periods in the day.

So after checking the biomechanics, what else can we measure to assess the effectiveness of breathing for sport? Testing the biochemistry of breathing is difficult without lab equipment, however there is an indicative measurement we can use that looks at the sensitivity of the body to rising CO2. It’s simply a short breath-hold after a normal exhale, until a desire to breathe is felt. The score is indicative of ineffective breathing if below 25 seconds. This test is known as the controlled pause, or Body Oxygen Level Test (BOLT) score. A low score is likely to be associated with early breathlessness during exercise and habitual mouth-breathing.

If someone is biomechanically breathing well, but still scoring low on CO2 sensitivity it could ultimately be a genetic factor, however CO2 tolerance is trainable. Two approaches to improve your BOLT score include slow, reduced breathing to the point of slight air hunger, and intermittent high CO2, low O2 training (IHHT). To the uninitiated IHHT are breath-holds performed during exercise which effectively simulate training at high altitude. It’s not for the faint-hearted but studies show an extra release of red blood cells from the spleen during the first strong breath-hold, and increased erythropoietin (EPO), both of which improve oxygen carrying capacity. Running economy in swimmers was shown to increase by 6% in reduced breath training. Repeated sprintability improved by around 33% over 4 weeks IHHT in elite rugby players. So whilst being breathless involuntarily is a disadvantage; voluntary breathlessness could be the solution! Increased tolerance to CO2 is a benefit, therefore delaying the onset of breathlessness.

As a competitive freediver (swimming long distances in the pool on one breath), I experimented with a range of breath-holding techniques which not only trained my CO2 tolerance, allowing for longer dives and a reduced risk of blackout, but also my ability to relax into perceived discomfort and therefore boost mental toughness.

The breath, and lack of it, is an undervalued and understudied resource in sports. With research groups led by scientists such as Xavier Woorons, and passionate practitioners such as Patrick McKeown, Brian McKenzie and Laird Hamilton, it appears that the use of functional and performance breath training will continue to move into the mainstream. On the US-equivalent to Dragon’s Den this year, a $500,000 investment went to a mouth-taping company based on the expected benefits for athletes. It seems it may pay to shut your mouth!

Holder of 5 National Records in freediving, Rebecca Coales is also a Yoga Sports Coach™, teaching functional yoga techniques and restorative yoga for sport, and an Oxygen Advantage breathing and hypoxic training instructor. Join a free 10-day breath challenge to explore whether these techniques could work for you. Details at

1. Cochrane Review (2013) Breathing Exercises for dysfunctional breathing/hyperventilation in adults [link]

2. Rundell, K.W (2002) Exercise-induced bronchospasm in the elite athlete. Sports Medicine 32 (9) p. 583 [link]

3. McConnell, A (2011) Breathe Strong, Perform Better

4. Bradley, H (2014) Breathing pattern disorders and functional movement. Intl J Sports Physical Therapy 9 (1) p28 [Link]

5. Hostetter et al (2016) Triathlete adapts to breathing restricted to nasal passage without loss of VO2 max. J Sport Human Perf 4 (1) p. 1 [link]

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