We all know that breathing techniques, called Pranayama, is very important in Yoga. So let’s focus on the components of the breathing process:
There is a common tendency to refer to breathing and respiration as the same thing. This is wrong. Breathing is a mechanical process, while respiration is a chemical process. Respiration refers to the process of carrying the inhaled oxygen to each cell of the body that needs it. Its by-product is carbon dioxide.
On average, an adult at rest inhales and exhales about 16 times every minute. Each time, about 500-700ml of air is taken in, and about the same amount is exhaled. However, not the whole of the amount we inhale is oxygen. In fact, only about 20% of it is oxygen. About 79% of it is nitrogen, while the rest is a mixture of carbon dioxide, helium, argon, and other gases. Almost as much nitrogen is exhaled as is inhaled each time. The only difference is that exhaled air contains only 16% oxygen and 4% carbon dioxide, which means that about one-fifth of the oxygen we take in is changed to carbon dioxide during respiration. Part of the aim of deep breathing exercises and posture movements in Yoga is to increase the amount of oxygen compared to that of carbon dioxide in the blood, which will circulate all over the body.
Oxygenation refers to the injection or addition of oxygen into any organism, and this includes the human body. In our case, oxygenation occurs in the blood cells, which in turn carries the oxygen throughout the body.
Now why is oxygen important? All living tissues and cells need energy in order to live. For us humans, we get this energy from the food we eat. After digestion, the energy is stored in the molecules of glucose, fructose, amino acids, and other substances. But it cannot just stay there; that energy must be released in order to be used. Energy can be released from those molecules through a chemical process that requires oxygen for it to take place. This is why oxygen, and eventually breath, is of paramount importance to our lives.
The nervous system is responsible for the regulation of breathing. It controls the contractions of muscles used in breathing. This starts from a cluster of cells in the brain stem called the respiratory centre. These cells send impulses to the different muscles involved in inhalation, which in turn takes in air. As for exhalation, it simply happens once inhalation stops. No force is necessary for exhalation; simply stop inhaling and exhalation will follow, thus completing the breathing cycle. That is why the cells of the respiratory centre can be compared to the pacemaker tissue of the heart, which acts without outside help.
However, like the heartbeat, some outside factors can influence the regularity of breathing. These can either be voluntary or involuntary. A few examples of voluntary factors are the control you exert over breathing when you are talking, singing, whistling, or when holding your breath when a certain smell offends you. Involuntary factors, on the other hand, are emotions such as fear, anger and excitement, as well as sudden changes in temperature.
The knowledge of regularity of breathing, particularly the voluntary and involuntary factors that affect it, is important in Yoga. This is because Yogic Breathing Exercises aim at changing unhealthy involuntary breathing habits voluntarily, then developing healthier habits afterwards.