School of Yoga explains Breath Control – prāṇāyāma physiology

            prāṇāyāma  physiology

Breathing is not just the source of life; it is also the source of health and happiness;

• The incoming breath is the source of oxygen which is carried by the blood to all organs. This rejuvenates tissues and optimises the oxidation process within the body.
• The outgoing breath removes carbon dioxide and water vapour, removing toxins and keeping the mucous balance in the lungs. 
• The pace of breathing changes with stress levels. When confronted with danger, our breathing becomes rapid and shallow to compensate for enhanced awareness and increased demand for oxygen from muscles involved in the response. 
• Finally, the balance in breathing between left and right nostrils determines the balance between left and right brain activity which affects analytical and creativity capability and output of the person. 

Yes, breathing is a critical aspect of life and living and prāṇāyāma is the science of regulating it.

School of Yoga explains – Breathing action…

• We breathe without noticing it. It is an involuntary action, performed without us being conscious of it.
• During breathing-in, we expand the chest so that the lungs admit air from the atmosphere.
• The diaphragm which forms the base of the thoracic cavity moves down.
• Consequently, this causes negative pressure within the lungs, leading to air being drawn through the mouth and nostrils into the wind pipe to reach the lungs.
• Similarly, during exhalation, the abdominal muscles contract, squeezing the abdominal viscera against the diaphragm.
• When the diaphragm is pushed up, lungs get compressed which forces air which is now filled with carbon dioxide and water vapour out of the body through the nostrils.

School of Yoga explains – Lung Capacity

In normal sedentary breathing, lungs do not get completely filled or emptied in each respiratory cycle. In fact, lungs have enormous reserve capacity and some of these aspects are;

• In each normal cycle of inhalation and exhalation, about 500 ml. of air is moved.
• During exhalation, a further measure of one litre (1000 ml) of air can be forced out.
• The lungs are not fully emptied even at this stage and still hold about 1200 ml. of air. This is called residual volume and this is air that cannot be forced out of the lungs.
• The greatest volume of air that can be taken in is called aspiratory capacity and this is about 3500 ml.
• After such an inhalation, the lungs hold nearly five litres (5000 ml) of air, and this is called total lung capacity. It is the addition of residual volume (1200 mi) and aspiratory volume (3500 ml).
• The maximum amount of air that a person can draw out after taking a deep breath is called vital capacity and it gives information about the strength of the respiratory muscles, the ability of the lungs and size of the thoracic cage.

School of Yoga explains – Breathing physiology:

Atmospheric air entering the lungs contains roughly 79% nitrogen, 20% oxygen, and traces of carbon dioxide. Out of these, only oxygen is used by the body. In exchange, the body gives up carbon dioxide and water vapour. 

The wind pipe (trachea) divides into two bronchi. Each bronchus enters the lung on its side and divides itself into several branches called bronchioles. The bronchioles further divide and sub-divide themselves into fine terminal branches, and these terminate into respiratory bronchioles that hold minute air sacks called alveoli. Alveoli have a very thin lining surrounded by thin-walled capillaries that facilitate exchange of gases. Though each alveolus is a very small microscopic structure, the number of alveoli in the lungs is enormous, providing an area of almost 50 square meters for exchange of gases.

The process of exchange of gases in the alveoli to and from the blood surrounding it is called diffusion. Oxygen moves from the air to the blood and is absorbed by the haemoglobin in the blood while carbon dioxide and water vapor diffuse from the blood to the alveolar air.

Absorption of oxygen and elimination of carbon dioxide and water vapor is the essence of respiration. This process goes on continuously in us as long as we live, without requiring our attention. The body changes various elements of respiration to suit the requirements of the body and these changes are governed by the nervous system.

School of Yoga explains – need for breathing!

Every living tissue and cell requires a constant supply of energy to live. This energy is stored in the molecules of substances such as glucose, fructose, fatty acids, and amino acids which are the end products of the process of digestion of food which we eat. Energy is released by the body through a process called oxidation a process that uses oxygen. So, when there is no oxygen, the process of release of energy comes to a halt and results in the death of that tissue.

It will be observed that in any fight/flight situation, such as while taking a long or high jump, or lifting a heavy weight etc., we automatically stop the breath. Breathing is also stopped when there is a sudden shock and when there is complete absorption of the mind in something interesting. This occurs because of intensity of focus. Also, while we are resting, breathing automatically slows down, but when there is physical activity and increased need of oxygen, breathing automatically becomes faster and deeper. Therefore, there is a definite linkage between breathing and the psychosomatic functioning of the body.
Disciplining the breathing process means increased absorption of oxygen & greater efficiency of the lungs.

Internal Links: Dharma (conditioning), Stress and Situational Awareness, Prana, Asana overview 1, Asana Overview 2, Asana Focus or gazing, Hatha Yoga Pradeepika 

External Links: Prana, Chakra, Pancha Tattva, Pancha Prana, Pancha Kosha, Nadi, respiration

Points to Ponder on breathing:

• Do you practice any form of aerobic breathing?
• What is your experience?
• Do you prepare yourself before starting exercises?
• What are the benefits you have experienced?
• Comment on breathing and health.
• Breathing and balanced thinking.
• What changes to your breathing have you have observed when you are stressed.