Help Prevent Exercise Induced Asthma

The Oxygen Advantage® By Patrick McKeown

Based on the fact that a number of clinical trials have shown that asthma symptoms and the need for asthma medication significantly reduces following the employment of reduced breathing exercises, there is no doubt that overbreathing is a significant contributor to asthma [7,9,10].

The first step to addressing chronic overbreathing is to make the switch from mouth to nasal breathing. While nasal breathing is important for everyone, for people prone to asthma it is vital. When breathing volume is greater than normal, there is a tendency to open the mouth in order to allow more air enter the lungs. People diagnosed with asthma often feel they are not taking in enough air while breathing through the nose, which causes them to breathe through the mouth [11,12].

A study at the Mater Hospital in Brisbane found that when the breathing volume of adults with asthma decreased from 14 litres to 9.6 litres per minute, their symptoms reduced by 70 percent, the need for rescue medication decreased by 90 percent, and the need for preventer steroid medication decreased by 50 percent [7]. The study found a direct relationship between the reduction of breathing volume and improvement to asthma. The closer breathing volume reduced toward normal, the greater was the reduction of asthma symptoms such as coughing, wheezing, chest tightness, and breathlessness. Furthermore, the trial’s control group – who were taught the hospital’s in-house asthma management program – made zero progress. The reason for this was solely due to the fact that there was no change to their breathing volume [7]. Further studies compounded these findings by showing that people with asthma who practiced reducing their breathing volume had far better asthma control with a significantly reduced need for preventive steroid and rescue medication within 3 to 6 months [9,10].

Mouth breathing influences asthma in a number of ways:

  • Air taken in through the mouth is not filtered of airborne particles, including germs and bacteria [13];
  • The mouth is simply not as effective as the nose in conditioning air to the correct temperature and humidity prior to entering the lungs [13];
  • Because the mouth provides a larger space to breathe through than the nose, breathing volume will be higher, causing too much carbon dioxide to be expelled from the lungs. Carbon dioxide is a natural “opener” of the smooth muscle in the airways. The loss of carbon dioxide therefore causes asthma airways to narrow even more;
  • Unlike nasal breathing, mouth breathing does not allow us to benefit from nasal nitric oxide, which supports the lung’s defensive capabilities [14,15,16].

Taking all these factors into consideration, it is not surprising that mouth breathing causes a reduction in lung function in people with mild asthma, and plays a significant role in the exacerbation of asthma symptoms [17].

Not only is it important to breathe through the nose during rest, it is also beneficial to nasal breathe during physical exercise. In a paper published in the American Review of Respiratory Disease, researchers studied the beneficial effects of nasal breathing on exercise-induced asthma. The study observed that most subjects with asthma spontaneously breathed with their mouths open when instructed to breathe “naturally.” The authors found that mouth breathing during exercise caused the airways to narrow even further. In contrast, when subjects were asked to breathe only through their nose during exercise, exercise-induced asthma did not occur at all. The paper concluded that “the nasopharynx and the oropharynx play important roles in the phenomenon of exercise-induced bronchoconstriction [18].” In simple terms, the effects of breathing through the nose are integral to reducing or avoiding exercise-induced asthma completely [19].

The fact that elite athletes with asthma often favor swimming above other forms of exercise is not a coincidence. During swimming, the face is immersed underwater, reducing the amount of air taken into the lungs and increasing the athlete’s tolerance for carbon dioxide. Although the swimmer may draw his or her breath in through the mouth, the protective effects of reduced breathing are still evident. A child or adult with asthma may also prefer swimming because the water exerts a gentle pressure on the chest and abdomen, further restricting breathing volume and improving athletic performance.

The difference between land-based exercise and swimming in terms of breathing pattern and volume is significant for people with asthma [20]. On land, your breathing pattern during exercise is not restricted the way it is in water, meaning that you can very easily overbreathe, resulting in constricted airways, a reduction in the amount of CO2 in your blood, and a lower BOLT score. For an individual with asthma, overbreathing during rest leads to overbreathing during exercise, which in turn leads to exercise-induced asthma. However, exercising in water naturally causes you to restrict your breathing and lower your breathing volume toward normal, providing a much safer and more productive environment for people with asthma to exercise [20].

One study showed that in a group of athletes, narrowing of the airways affected 55 percent of football athletes and 50 percent of basketball athletes, but 0 percent of water polo athletes [2]. With such a glaring disparity, what factors could possibly explain the difference? The answer, as you have probably guessed by now, is simple. Water polo training involves breath holding and swimming underwater, resulting in a higher tolerance to carbon dioxide, increased amounts of nitric oxide and a reduced breathing volume. With a more normal breathing volume, asthma tendencies don’t appear.

However, if you have asthma and do not wish to take up swimming, there is a simpler way! The Oxygen Advantage® approach incorporates all of the beneficial aspects of swimming and more. Although the act of swimming has its merits, it is well documented that spending time in chlorinated pools is not ideal for asthma, as the chlorine can cause damage to lung tissue [21-24].  Furthermore, while swimming reduces breathing volume, it is still important to address poor breathing habits outside of the pool. Many swimmers remain habitual mouth breathers and continue to employ poor breathing habits that reduce their athletic performance and maintain their asthma.


    1. Rundell KW, Im J, Mayers LB, Wilber RL, Szmedra L, Schmitz HR. Self-reported symptoms and exercise-induced asthma in the elite athlete. Med Sci Sports Exerc.2001 Feb;33(2):208-13
    2. Sidiropoulou MP, Kokaridas DG, Giagazoglou PF, Karadonas MI, Fotiadou EG. Incidence of exercise-induced asthma in adolescent athletes under different training and environmental conditions. J Strength Cond Res.2012 Jun;(26(6)):1644-50
    3. Zinatulin S.N. HEALTHY BREATHING: Advanced Techniques. 1st ed. Dinamika Publishing House; 2003
    4. McArdle William, Katch Frank L, Katch Victor L. Pulmonary structure and function. In: (eds.) Exercise Physiology: Nutrition, Energy, and Human Performance . 1st ed. United States: Lippincott Williams & Wilkins; Seventh, North American Edition edition ; (November 13, 2009). p263
    5. Johnson BD, Scanlon PD, Beck KC, Regulation of ventilatory capacity during exercise in asthmatics, J Appl Physiol. 1995 Sep; 79(3): 892-901.
    6. Chalupa DC, Morrow PE, Oberdörster G, Utell MJ, Frampton MW, Ultrafine particle deposition in subjects with asthma Environmental Health Perspectives 2004 Jun; 112(8): p.879-882.
    7. Bowler SD, Green A, Mitchell CA, Buteyko breathing techniques in asthma: a blinded randomised controlled trial. Med J of Australia 1998; 169: 575-578.
    8. GINA. GINA Report, Global Strategy for Asthma Management and Prevention
    9. McHugh P, Aitcheson F, Duncan B, Houghton F.. Buteyko Breathing Technique for asthma: an effective intervention. The New Zealand Medical Journal.2003 Dec 12;116(1187)
    10. Cowie RL, Conley DP, Underwood MF, Reader PG.. A randomised controlled trial of the Buteyko technique as an adjunct to conventional management of asthma. Respiratory Medicine.2008 May;102(5);726-32
    11. Hallani M, Wheatley JR, Amis TC. Initiating oral breathing in response to nasal loading: asthmatics versus healthy subjects. European Respiratory Journal.2008;(Apr;31(4)):800-6
    12. A paper published in the medical Journal Chest which noted that “asthmatics may have an increased tendency to switch to oral (mouth) breathing, a factor that may contribute to the pathogenesis of their asthma.”See: Kairaitis K, Garlick SR, Wheatley JR, Amis TC. Route of breathing in patients with asthma. Chest.1999;(Dec;116(6)):1646-52
    13. Fried R. In: (eds.)Hyperventilation Syndrome: Research and Clinical Treatment (Johns Hopkins Series in Contemporary Medicine and Public Health). 1st ed. : The Johns Hopkins University Press ; December 1, 1986.
    14. Djupesland PG, Chatkin JM, Qian W, Haight JS. Nitric oxide in the nasal airway: a new dimension in otorhinolaryngology. Am J Otolaryngol.2001 Jan-Feb;(22(1)):19-32
    15. Scadding G. Nitric oxide in the airways. Curr Opin Otolaryngol Head Neck Surg.2007 Aug;(15(4)):258-63
    16. Vural C, Güngör A.. [Nitric oxide and the upper airways: recent discoveries]. Tidsskr Nor Laegeforen.2003 Jan;(10(1)):39-44
    17. Hallani M, Wheatley JR, Amis TC. Enforced mouth breathing decreases lung function in mild asthmatics. 6) Respirology.2008;(Jun;13(4)):553-8
    18. Shturman-Ellstein R, Zeballos RJ, Buckley JM, Souhrada JF. The beneficial effect of nasal breathing on exercise-induced bronchoconstriction. American Review Respiratory Disease.1978; (Jul;118(1)):65-73
    19. Researchers studied the effects of nasal breathing and oral breathing on exercise-induced asthma. Fifteen people were recruited for the study and asked to breathe only through their nose. The study found that ‘the post-exercise bronchoconstrictive response was markedly reduced as compared with the response obtained by oral (mouth) breathing during exercise, indicating a beneficial effect of nasal breathing’.See: Mangla PK, Menon MP. Effect of nasal and oral breathing on exercise-induced asthma. Clin Allergy.1981;(Sep;11(5)):433-9
    20. In the words of respiratory consultant Dr Peter Donnelly, which were published in the medical journal The Lancet, ‘In most land based forms of exercise, patterns of breathing are not constrained, ventilation increases proportionately throughout exercise and end tidal CO2 tensions are either normal or low. Therefore, there is no hypercapnic (increased carbon dioxide) stimulus for bronchodilation (airway opening) and asthmatics have no protection’.See: Donnelly Peter M. Exercise induced asthma: the protective role of Co2 during swimming. The Lancet.1991;(Jan 19;337(8734):):179-80
    21. Uyan ZS, Carraro S, Piacentini G, Baraldi E. Swimming pool, respiratory health, and childhood asthma: should we change our beliefs? Pediatr Pulmonol.2009 ;(Jan;44(1)):31-7
    22. Fjellbirkeland L, Gulsvik A, Walløe A . Swimming-induced asthma. Tidsskr Nor Laegeforen. 1995 Jun 30;(115(17)):2051-3
    23. Bernard A, Carbonnelle S, Michel O, et al . Lung hyperpermeability and asthma prevalence in schoolchildren: unexpected associations with the attendance at indoor chlorinated swimming pools. Occup Environ Med .June 2003;(60 (6)):385–94
    24. Nickmilder M, Bernard A.. Ecological association between childhood asthma and availability of indoor chlorinated swimming pools in Europe. Occup Environ Med.2007 Jan;(64(1)):37-46