Exercise as it relates to Disease/Benefits of nasal breathing compared to oral breathing in regards to exercise-induced Asthma

This wiki page is a critical appraisal of a published research article relating to exercise-induced asthma and nasal breathing versus oral breathing. This appraisal is part of an assignment with the University of Canberra, Unit; Health Disease & Exercise.

Mangala PK, Menon MPS. (1981) Effect of nasal and oral breathing on exercise-induced asthma. Clinical Allergy. Vol 2 pp 433-439

What is the background to this research?
Asthma is a chronic inflammation of the airways involving bronchoconstriction (a tightening of the smooth muscle around the bronchiole and narrowing of the airway), mucous secretion and airway remodelling. Exercise-induced asthma (EIA) is characterised as the above symptoms when brought on by exercise as the increased volume of air irritates the airway. Nasal breathing throughout exercise is one suggested method of alleviating exercise induced asthma and the basis of this study. Research in to whether nasal breathing can in fact reduce EIA is critical as it is a deterrent to many people undertaking physical activity through fear of triggering their EIA symptoms. This study compares nasal breathing to mouth breathing during vigorous exercise to record how each style of respiration affects the airways. EIA in this study is defined as a 20% or greater decrease in Forced Expiratory Volume (FEV) from baseline measures. Despite the associated benefits, nasal breathing is not commonly practiced throughout vigorous physical activity due to a lack of awareness of the benefits coupled with a reduced capacity to dump carbon dioxide. This results in a phenomenon described as air hunger and causes a switch to oral breathing.

Where is the research from?
This research by P.K. Mangala and M.P.S. Menon comes form the University of Delhi, India. This is important information to consider due to the air temperature and humidity at the time of the study of between 32-35°C and 50-70% humidity. This air temperature is ideal for people with EIA in reducing bronchoconstriction whilst lower or higher temperatures can negatively effect EIA. Similarly the humidity of 50-70% at the time of the study has been shown to be ideal for EIA as opposed to dry air. Mangala has done limited research relating to exercise induced asthma with just one other study on EIA and Aspirin. Menon has been involved in several published studies relating to asthma. It is worth mentioning that one of the referenced articles in this study was Mangalas’ own thesis and is not available online for review.

What kind of research was this?
This research was a case control experimental study. Designed to replicate two breathing phenomenon in a controlled environment to discover the effects of each on both asthma sufferers with and without EIA and non asthma sufferers. The variable, method of respiration was manipulated to determine its effect on other variables like FEV post exercise in all groups.

What did the research involve?

 * An initial study was undertaken to detect the prevalence of EIA that enabled participants to be selected and placed in one of three groups
 * Non asthmatics, asthmatics with EIA, asthmatics with no EIA


 * FEV, heart rate (HR) and blood pressure baseline readings were recorded
 * A 6 minute maximum intensity run was completed by each individual. Once with a clipped nose and once with a taped mouth in a randomised sequence.
 * FEV was tested at the end of the run and 5, 10, 15, 20 and 30 minutes post run.
 * A greater than 20% decrease in FEV post exercise was recorded as EIA
 * The results of FEV, HR and blood pressure post oral breathing and nasal breathing exercise were compared

What were the basic results?
The important findings of this study were the improvement of EIA symptoms in asthmatics with EIA when they performed nasal breathing instead of mouth breathing during exercise. This was also the case for the non-asthmatic group. The researchers optimistically interpreted that in all three groups, mouth breathing caused a greater decrease in FEV however then went on to say that in asthmatics with no EIA there was not significant changes in FEV. The second statement is supported by Table 2 and Fig 2.

What conclusions can we take from this research?
The observation of wheezing that was present after mouth breathing and not present after nasal breathing in the asthmatic EIA group is a subjective observation that can also be altered. The wheeze also wasn’t recorded for any of the other groups and therefor has little relevance to the results of the study. The researchers could have been more transparent about the insignificant changes for the asthmatics with no EIA and perhaps mentioned that more study could be done on this group in cooler or dryer conditions to observe if nasal breathing becomes more relevant in less ideal conditions.

The findings in HR and blood pressure differ to some more recent research that also measures HR, blood pressure and FEV during both nasal and oral breathing exercise. The more recent research found that HR did in-fact differ during maximum effort exercise bouts of nasal breathing and oral breathing. It’s worth noting that HR and respiration rate both stayed lower when nasal breathing whilst performance was the same. This may be advantageous information to those affected by EIA.

The study by Mangala and Menon doesn’t mention how HR was recorded. It also refers to HR recordings in table 2 however table 2 only reports on FEV. The observation about HR not differing between nasal breathing and mouth breathing may be unreliable.

Practical advice

 * Complexity and unpredictability of real world implications include, pollen or pollution affecting air quality, emotional state of the individual, fitness level, temperature and humidity; other factors that contribute as EIA triggers.
 * Asthma sufferers at risk of EIA should always seek medical advice before attempting any form of vigorous activity that could trigger EIA and if medication has been prescribed by a medical professional it should be administered as instructed.
 * The research considered, suggests that nasal breathing throughout exercise should be investigated as an aid to those who experience EIA. A good base of aerobic fitness is also beneficial in reducing EIA symptoms. Exercise should be monitored, intensity should be gradually increased over time and always undertaken with supervision for asthma sufferers with EIA.
 * Nasal breathing as a means to improve performance should be considered by athletes who experience EIA.

Further information
The National Asthma Council of Australia have a very informative and up to date handbook available online for anyone wanting more information on asthma and EIA as well as links to medical support, action plans and support groups.