Bronchoconstriction: Causes and Treatment
(definition) is defined as the narrowing of the airways in the lungs (bronchi and
bronchioles). Air flow in air passages can get restricted due to 3 factors:
- a spasmodic state of the smooth muscles in bronchi and bronchioles
- an inflammation of the airways
- excessive production of mucus due to an allergic reaction or irritation caused
by mechanical friction of air (due to shear stress), overcooling or drying of
Bronchoconstriction is common in people with respiratory problems,
such as asthma, COPD, and cystic fibrosis.
Medical sources continue to misinform public about the true causes of
bronchoconstriction. Here are the facts.
Ventilation rates (chronic diseases)
| All references or
click below for abstracts
|| Medical textbooks
|| Results of 14 studies
||13 (+-2) L/min
|| Chalupa et al, 2004
|| Johnson et al, 1995
||14 (+-6) L/min
|| Bowler et al, 1998
||13 (+-4) L/min
|| Kassabian et al, 1982
|| McFadden, Lyons, 1968
||14 (+-2) L/min
|| Palange et al, 2001
||12 (+-2) L/min
|| Sinderby et al, 2001
|| Stulbarg et al, 2001
Fauroux et al, 2006
Browning et al, 1990
Ward et al, 1999
|CF and diabetes*
Ward et al, 1999
Dodd et al, 2006
McKone et al, 2005
||13 (+-2) L/min
|| Bell et al, 1996
|| Tepper et al, 1983
As a result of heavy breathing, all these people suffer from alveolar hypocapnia
(lack of CO2 in airways).
Cause of bronchoconstriction
It is a known physiological law that all smooth
muscles are highly sensitive to CO2 levels. Thus,
spasm in the smooth muscles of bronchi and bronchioles
is a normal physiological reaction to alveolar hyperventilation (Badier
et al, 1998; Clarke et al, 1982; Jamison et al, 1987; O'Cain et al, 1979;
While there are many chemicals that can cause either bronchoconstriction or
bronchodilation, CO2 plays the key role due to two factors: its high bronchodilatory
potency and additional negative systemic effects caused by alveolar hypocapnia (lack
of CO2). What are those?
Chronic hyperventilation (breathing more air than the
medical norm) also leads to cell hypoxia, generation of reactive oxygen species
(free radicals), and immunosuppression. (This can happen
with or without ventilation-perfusion mismatch: blood CO2 levels can be below
the norm or too high.)
As a result, overbreathing produces additional effects
that worsen conductivity of airways, such as immunosuppression,
frequent respiratory infections, excessive production of sputum (mucus)
and airway inflammation (see links to studies below).
Furthermore, overbreathing also leads to increased losses of water from the
mucosal layers of airways and overcooling of airways due to increased heat
losses. These effects also favor frequent respiratory infections.
Symptoms of bronchoconstriction
These effects cause further airway obstruction, difficulty
breathing, wheezing, coughing, and dyspnea (shortness of
breath) amplifying the effects of bronchoconstriction.
Causes and mechanism of bronchoconstriction
Consider medical evidence related to breathing parameters at rest in people with
bronchoconstriction (see the Table above). We see that
these patients breathe at rest (in stable conditions) much more
air than the medical norm. Over breathing leads to low CO2 in the airways
and causes other effects summarized here.
Bronchoconstriction can also happen due to an allergic reaction caused by the release of
histamine. This allergic reaction leads to edema and inflammation
of airways, as often happens in people with asthma, bronchitis, emphysema, and
other COPD-related conditions. However, chronic hyperventilation causes immune
dysfunction, and, therefore, it also promotes the appearance of allergies.
Since cell hypoxia promotes
chronic inflammation, people with these health conditions (asthma,
bronchitis, and so on), as well as people with cystic fibrosis,
tuberculosis, sarcoidosis, bronchiectasis,
bronchiolitis, and many other lung diseases, experience chronic spasm in
the smooth muscles of airways or bronchoconstriction, combined with other negative
effects caused by hypocapnia.
This YouTube video explains the cause of bronchoconstriction.
Note about coughing. Coughing through the mouth multiplies all these
negative effects of hyperventilation several fold. There are effective
breathing techniques how to suppress
Treatment of bronchoconstriction
Six most effective clinical controlled trials on asthma cannot be wrong. They achieved 90% reduction in main asthma medication that is used to produce ... bronchodilation. In other words, asthmatics can reduce their main symptom (spasm of airways) with a simple natural reduced breathing exercise based on increasing CO2 levels in the lungs and airways.
What are the origins of this technique? Over
170 Russian medical doctors found an effective way to deal with
bronchoconstriction. This medical treatment is based on restoration of normal
alveolar CO2 levels naturally or using will power. The Buteyko method is approved by the Russian Ministry
of Health and has been applied on more than 200,000 people with health problems
that involve bronchoconstriction (such as asthma, bronchitis, COPD, cystic
fibrosis and many others).
According to these Russian doctors, patients need to slow down their heavy
breathing and achieve more than 20 s
for the body-oxygen test to prevent symptoms of bronchoconstriction at rest. Nose
breathing during exercise is crucial since it prevents
However, I tested the Buteyko technique and compared it with other respiratory techniques. There are methods that are even better than the legendary Buteyko techinque to reduce constriction of airways and defeat common respiratory diseases, such as asthma, bronchitis, COPD, emphysema, cystic fibrosis, and others. You can find the names of these great methods right below here as your bonus content.
Lifestyle changes are also necessary to prevent
overbreathing due to sleep (supine sleep and mouth breathing), meals
(overeating), exercise, and other factors.
Badier M, Beaumont D, Orehek J, Attenuation of hyperventilation-induced
bronchospasm by terfenadine: a new antihistamine, J Allergy Clin Immunol.
Clarke PS, Jarrett RG, Hall GJ, The protective effect of ipratropium bromide
aerosol against bronchospasm induced by hyperventilation and the inhalation of
allergen, methacholine and histamine, Ann Allergy. 1982 Mar;48(3):180-3.
Jamison JP, Glover PJ, Wallace WF, Comparison of the effects of inhaled
ipratropium bromide and salbutamol on the bronchoconstrictor response to
hypocapnic hyperventilation in normal subjects, Thorax. 1987 Oct; 42(10):
....This suggests that bronchoconstriction in response to hypocapnic
hyperventilation in normal subjects is not mediated via a cholinergic reflex.
O'Cain CF, Hensley MJ, McFadden ER Jr, Ingram RH Jr, Pattern and mechanism of
airway response to hypocapnia in normal subjects, J Appl Physiol. 1979
We examined the bronchoconstriction produced by airway hypocapnia in normal
subjects... Pretreatment with a beta-sympathomimetic agent blocked the response,
whereas atropine pretreatment did not, suggesting that hypocapnia affects airway
smooth muscle directly, not via cholinergic efferents.
Reynolds AM, McEvoy RD, Tachykinins mediate hypocapnia-induced
bronchoconstriction in guinea pigs, J Appl Physiol. 1989
... We conclude that, in the guinea pig lung, HIBC [hypocapnia-induced
bronchoconstriction] is mediated by TKs [tachykinins] that are released
after the activation of bronchial axonal reflexes.
Sterling GM, The mechanism of bronchoconstriction due to hypocapnia in man,
Clinical Science 1968 Apr; 34(2): p. 277-285.
Straub NC, Section V, The Respiratory System, in Physiology,
edited by. Berne RM & Levy MN, 4th edition, Mosby, St. Louis, 1998.
* Upper illustration by Victor Lunn-Rockliffe
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