The body is made up of the five elements-earth, water, fire, air and space with each body system related to a particular element, i.e. the skeletal system is related to earth, the circulatory and immune systems to water, the respiratory system to air, the digestive system to fire, and the central nervous system to space.
The body is experienced through hearing, smelling, tasting, seeing, feeling and thinking. But, primarily the body is known through feeling. The body is a feeling-object unfolding as sensation in Awareness. The body as a concept is built up within the thinking mind and is conditioned through memory, reaction and compensation.
When we feel separate, we live conceptually as the body, which has defined boundaries. Through active inquiry we come to realize that the body is a projection in us.
The body is a percept, not a concept. Sensing the body dissolves its objective solidity as the earth element, revealing the other elements of water, fire, air and space each of which, in turn, dissolves into its prior cause until the body dissolves totally into its non-objectivenature as Awareness. Body sensing purifies the objectified body of its conditioned nature to reveal its true radiant transparency.
Hatha Yoga is the science of inquiring into the substance and reality of the physical body. Asana, supported by pranayama and visualization, is one tool we use to investigate the reality of the physical body.
2. The energy body - Pranamaya Kosha
Prana (with a capital 'P') is the life force that animates the universe and gives life to the physical body. Prana is not separate from Awareness, which is the source of prana as well as the body. Prana is therefore a projection of Awareness.
Prana as the enlivening principle of the body is divided into five functions, or airs, as described in the Chandogya Upanishad (II.13.6).
Apana governs and regulates the eliminative system. Its field of activity is from the navel to the soles of the feet and it is represented by the element of earth. Its nature is heavy and it is related to exhalation, which has a downward feeling of movement to it as well as an upward movement in the diaphragm.
The energy body is regulated through asana, pranayama. Each asana and pranayama is related to and influences a particular vayu. Through pranayama we open to the subtle body, which brings a sense of transparency to subtle layers of conditioning and the reactive mind2.
Samana governs and regulates the digestive system. Its field of activity is from the heart to the navel and is represented by the element of water. Its nature is cool and it is related to circular movement in the abdomen.
Prana (with a small 'p') governs and regulates the respiratory and cardiovascular systems. It field of activity is from the mouth to the heart and it is represented by the element of fire. Its nature is light and it is related to inhalation, which has an upward feeling of movement to it as well as a downward movement in the diaphragm.
Udana governs and regulates eating, drinking and speaking. Its field of activity is the throat and it is represented by the element of air, which moves throughout the body.
Vyana governs and regulates prana into the limbs. Its field of activity is throughout the body and is represented by the element of space. Its nature is spaciousness throughout the body.
3. The body of feeling and emotion - Manomaya Kosha