Dry Cough Causes and Home Remedies for Dry Cough
Chronic (persistent) dry cough is a respiratory symptom of chronic hyperventilation and low body O2. Commonly causes of dry cough include health problems such as with asthma, bronchitis, COPD, cystic fibrosis, numerous lung conditions and during respiratory infections. It often gets worse during sleep or at night, on exertion, and after meals.
During normal breathing at rest the air travels though the nasal cavities at a speed of 8 km/h. When we cough through the mouth, the air rushes out through the airways at 120-160 km/h. This causes mechanical stress (irritation) and sudden CO2 losses with the following effects of alveolar hypocapnia (low CO2 levels in airways): bronchospasm (constriction of airways); irritable state of the cough receptors; and greatly increased mechanical friction in airways due to strong air flow. Later, due to reset in the breathing center, overbreathing and irritation of airways become chronic.
First of all, hundreds of scientific publications have proven that hyperventilation causes reduced body-oxygen content due to alveolar hypocapnia (low CO2 levels in the lungs). Furthermore, decades of medical research have proven that low CO2 over-excites nerve cells making them irritable. This effect (over-excitement of nerve cells) also takes place with the nerve cells that control the urge-to-cough reflex that usually appears due to some additional irritation (or trigger) in the chest or upper airways.
Bouts of coughing cause (see references below):
- irritable state of cough receptors in the tracheobronchial tree and larynx due to hypocapnia (low CO2 in these nerve cells)
- constriction of airways due to hypocapnia (since CO2 is a bronchodilator)
- chronic respiratory infections and inflammation due to suppression of the immune system caused by cell hypoxia and other effects caused by hyperventilation.
Coughing through the mouth creates a huge air pressure graduate that can easily damage or even rupture alveoli, our tiny air sacks, which make gas exchange in the lungs possible. Coughing is particularly dangerous for people with bronchitis or emphysema. Hence, due to purely mechanical effects, coughing causes:
1) damage and rupture of tiny and fragile air sacks (alveoli) due to very large pressure gradient and sudden change in air pressure in the tissues of the lungs (lungs tissue is very weak and is easily damaged due to mechanical over stimulation caused by coughing)
2) mechanical irritation of the constricted and inflamed airways due to large movements of air and excessive friction due to sudden changes in pressure.
Hence, the more you cough (especially through the mouth), the more CO2 you remove, and the worse your symptoms become.
Natural Home Remedies for Dry Cough
Over 180 Russian medical doctors (practicing the Buteyko breathing method) developed simple breathing techniques to reduce coughing and eventually eliminate and get rid of all types of coughing symptoms, including dry persistent cough.
These doctors also discovered that this symptom usually disappears when the patients slow down their automatic breathing and get over 20 s for the body-oxygen test.
- Stop Coughing At Night - Another breathing technique and exercise to get rid of chronic or persistent coughing and fall asleep faster.
Reference pages: Breathing norms and the DIY body oxygen test:
- Breathing norms: Parameters, graph, and description of the normal breathing pattern
- Body-oxygen test (CP test) : How to measure your own breathing and body oxygenation (two in one) using a simple DIY test
References: pages about CO2 effect:
- Vasodilation: CO2 expands arteries and arterioles facilitating perfusion (or blood supply) to all vital organs
- The Bohr effect: How and why oxygen is released by red blood cells in body tissues
- Nerve stabilization: Carbon dioxide has powerful calmative and sedative effects on brain neurons and nerve cells
J Assoc Physicians India. 2000 Mar;48(3):343-5.
The role of cough and hyperventilation in perpetuating airway inflammation in asthma.
Singh V, Chowdhary R, Chowdhary N.
Department of Pulmonary Medicine, SMS Medical College, Jaipur-302 016, India.
Air flowing through a pipe exerts frictional stress on the walls of the pipe. Frictional stress of more than 40 N/m2 (velocity equivalent of air 113 m/s) is known to cause acute endothelial damage in blood vessels. The frictional stress in airways during coughing may be much greater, however, since the velocity of air may be as high as speed of sound in air. We suggest that high levels of frictional stress perpetuate airway inflammation in airways which are already inflamed and vulnerable to frictional stress-induced trauma in patients with asthma. Activities associated with rapid ventilation and higher frictional stress (e.g. exercise, hyperventilation, coughing, sneezing and laughing) cause asthma to worsen whilst activities that reduce frictional stress (Yoga 'Pranayama', breathing a helium-oxygen mixture and nasal continuous positive airway pressure) are beneficial. Therefore control of cough may have anti-inflammatory benefits in patients with asthma.
Jpn J Physiol. 1991;41(6):879-91.
Influence of central respiratory activity on the cough response in anesthetized dogs.
Suzuki H, Kondo T, Yamabayashi H, Kobayashi I, Ohta Y.
Department of Medicine, Tokai University School of Medicine, Isehara, Japan.
Cough responses evoked by mechanical stimulation of the tracheobronchial mucosa in anesthetized and tracheostomized dogs were studied... Coughing could be evoked when the dog was made apneic either by hyperventilation or by the Hering-Breuer reflex...
Handb Exp Pharmacol. 2009;(187):263-76.
Clinical cough I: the urge-to-cough: a respiratory sensation.
Department of Physiological Sciences, Box 100144, HSC, University of Florida, Gainesville, FL 32610, USA.
Cough is generated by a brainstem neural network. Chemical and mechanical stimulation of the airway can elicit a reflex cough and can elicit a cognitive sensation, the urge-to-cough. The sensation of an urge-to-cough is a respiratory-related sensation. The role of the respiratory sensation of an urge-to-cough is to engage behavioral modulation of cough motor action. Respiratory sensations are elicited by a combination of modalities: central neural, chemical, and mechanical. Stimulation of respiratory afferents or changes in respiratory pattern resulting in a cognitive awareness of breathing are mediated by central neural processes that are the cognitive neural basis for respiratory sensations, including the urge-to-cough. It is proposed that the urge-to-cough is a component of the cough motivation-to-action system. The urge-to-cough is induced by stimuli that motivate subjects to protect their airway by coughing...
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