The Science of Pranayama: Understanding the Respiratory System

One of the mystical aspects of our yoga practice is the understanding of Pranayama. Pranayama is made up of 2 words, Prana and Ayama. "Prana" is the essence or energy of life, and "ayama" means to expand or control. So literally, Pranayama means the practice to expand/control the energy of life.

Prana manifests itself differently on different levels. On a physical level, Prana manifests itself into energy, which we absorb through different parts of our body in order to give us energy to live.

Different sources of Prana as energy that we take in order to live are Prana as food and water, Prana as sunlight, and most importantly Prana as breath. Why is Prana as breath so important? Simply because we can survive without food for 2 weeks, without water for 1 week, but we cannot survive without breathing for more than 3 minutes.

Breath is an important yet invisible part of our daily lives. A gentle deep breath can instantly calm our senses, emotions, and reintroduce as sense of awareness into our everyday activities. It can help control, anger, anxiety and nervousness, and bring into our lives a sense of grounding and stability. This fact alone makes the art and science of breathing a very important aspect to study. An understanding of how the respiratory system works helps us to clearly understand the working of the breath on a physical level, and greatly enhances and improves our pranayama practice.

In this article, we will study the physiology and anatomy of our Chest cavity and its physical working in the body.
Before we begin to understand the anatomy of the respiratory system, let us understand the purpose of breathing. Why do we breathe? The simple answer is - “All for the cells"
The purpose of breathing is to provide energy to our cells. Trillions of them, which tirelessly work day and night nonstop to sustain the body. Compare the cells in our body to the thousands of homes, offices, factories in a city. The central energy grid must continuously provide energy to these homes, offices and factories in form of electricity, water and gas in order for the homes to function properly. By being aware that external physical breathing is only an instrument for inner cellular breathing, we establish a deeper intimate relationship with ourselves, which is of respect and harmony.



Chest cavity

A thin dome shaped muscle called the diaphragm divides our chest cavity and abdomen. It forms the floor for the respiratory organs and roof for the organs of digestion.
The respiratory structure consists of a rib cage, which surrounds the lungs and the heart. Our body consists of two lungs, one on the right and one on the left. The right lung consists of three chambers, whereas the right lung comprises of two chambers. This is because the left lung must accommodate space for heart.
The ribcage is made up of bones, cartilage and muscles. The lungs do not have an independent capacity to expand or contract. They are connected to the walls and the floor of the rib cage with muscles. The lungs expand and contract with the expansion and contraction of the muscles.

Abdomen and Pelvis

This contains our organs of digestion, excretions and reproduction.


There are two main group of muscles, which help us to breathe.
1. Primary Respiratory Muscles
2. Secondary Respiratory Muscles.
Primary Respiratory Muscles:Our primary Respiratory muscles consist of Intercostal Muscles, 4 layers of Abdominal Muscles and Diaphragm .These are large and strong muscles which are located in the mid rib cage and the abdomen area of the body and do bulk of the work during respiration.
Secondary Respiratory Muscles: Our Secondary Respiratory Muscles consist of Scalene, Sternocleidomastoid, Trapezius and Pectorals Minor muscles. These muscles are located higher up in the torso and play a helping hand in the process of breathing.






The primary Muscles of Respiration are required to do 80% of the work and the Secondary muscles of Respiration are required to do 20 % of the work. This is good breathing.
The main muscle responsible for almost 75% of the effort during the process of breathing is the Diaphragm.
During inhalation, the intercostal muscles (11 pairs that occupy spaces between 12 pairs of ribs) fan outwards, The Diaphragm moves downwards and the abdomen moves forward. This allows for expansion in the chest. In this moment, the pressure in the atmosphere exceeds the pressure, which is inside our chest. As a result, air rushes inside our lungs to balance the pressure. During exhalation the diaphragm relaxes and moves back to its original positions, thus again balancing the pressure inside the lungs and the atmosphere. This process repeats all day for about 21600 times.
In our next article, we will study the working of the lungs, and how it helps in the process of breathing.