Old hatha yoga books suggest that breathing is the essence of hatha yoga training. It is much more fundamental than learning or mastering most difficult yoga poses or asanas.
Which breathing or respiration matters most? The breathing process is going on 24/7 and the body requires O2 all the time. Hence, it is necessary to have a closer look at our unconscious or basal breathing.
Classical manuscripts on Hatha Yoga (Gheranda Samhita, Hatha Yoga Pradipika, and Shiva Samhita) were written about 5-7 centuries ago. What do they say about breathing? According to these ancient hatha yoga manuscripts, the goal of hatha yog is to “suspend”, “hold”, “restrain”, and “calm” our breathing.
Unfortunately, modern yoga gurus, leaders and instructors teach and express opposite views in regard to involuntary or basal breathing patterns. Contemporary yoga leaders and practitioners believe in toxic waste nature of CO2 gas. They also promote the deep breathing myth claiming that our basal or unconscious breathing should be deep or large (for better health).
There are now dozens of proven benefits of carbon dioxide for the human body. It is vital for our health. If it gets 4 times below the medical norm, we can die in minutes due to spasms of blood vessels and severe tissue hypoxia in the brain and heart.
Elevated carbon dioxide content or mild arterial hypercapnia is the central factor that explains exceptionally slow respiration rates in some hatha yoga gurus (only about 3 breaths per minute at rest or during sleep) and exceptionally high body oxygen levels.
Normal and sick people often take more than 20 breaths per minute at rest depending on their health state. Faster breathing decreases body CO2 causing constriction of blood vessels (CO2 is the most potent tested vasodilator) and the suppressed Bohr effect (less oxygen is released in body tissues and vital organs at low CO2 levels). Furthermore, tiny normal diaphragmatic breathing is sufficient for 98% saturation of the arterial blood with oxygen. Overbreathing cannot provide more oxygen for us. It only reduces alveolar and arterial CO2 (if there are no problems with lungs).
Hence, slow unconscious breathing pattern provides people with higher cellular oxygenation.
Other confirmed properties of CO2 include: sedative or calmative effects on nerve cells, bronchodilation (dilation of airways), suppression of inflammation, abilities to heal lungs and other tissues, strong muscle relaxant, powerful antioxidant abilities (suppression of free radicals), regulator of hundreds of chemical reactions.
In agreement with old traditional yoga books and teaching, it was found that with slower breathing, breathing retraining students start to sleep much less (down to 2-3 hours without any voluntary limitations, if they get up to 2-3 min for the body oxygen test) if they manage to slow down their breathing down to 3-4 breaths per minute at rest. They start to crave physical exercise naturally, have exceptionally strong immune systems, can digest wider varieties of foods, and so forth.
These discoveries were made by the leading Soviet physiologist Dr. Konstantin Buteyko, MD, PhD who created the legendary Buteyko breathing technique. Dr. Buteyko studied the effects of breathing retraining in thousands of patients. He also analyzed effects of yoga asanas and found that many of yoga poses can only be performed while holding one’s breath. Hence, a challenging yoga practice naturally involves many breath holds and short transitions between them.
The main yoga breath work (hatha yoga pranayama) requires gradual increase in durations of all phases of the breathing cycle also leading to accumulation of carbon dioxide.
Best yoga gurus, when they do pranayama, have only 1 deep breath for every 2-3 minutes. They breathing may seem deep, but they reduce their minute ventilation and raise their arterial CO2, thus retraining their breathing center located in the brain to increased CO2 levels.
Hence, their basal breathing pattern later, after this breath work, becomes slower and lighter. This is possible since any medical textbook claims that breathing is regulated not by oxygen want, but by arterial CO2 levels.
Hence, slow breathing is the key to health and, if you manage to achieve it, you will be in excellent health.