Asanas and cellular system - B.K.S. Iyengar

“If the karmendriya is tamed by yama, the Jnanendriya is tamed by niyama. But the cellular system must be attended to, because the physiological body is the medium linking the skeletal body and the mental body. Unless we discover these links by ourselves, within ourselves, we cannot study yoga properly. Changes in the personality take place when one gains control over the organs of action and the senses of perception. Here, a ‘jump forward’ takes place in the human system. If the cellular system is unhealthy, illness follows. So, the cells must be made healthy. Hence, the practice of asana is given as the third petal of yoga. Let me illustrate the intricacies involved by referring to a few of the asanas. 

When you do Utthita Trikonasana, you stretch both the legs downward towards the feet. Then you suck the energy of the feet upwards, connecting the joints of the legs in order to re-adjust the torso to feel oneness and concord between body, mind and self.

When you do Utthita Parsvakonasana, while bending one knee, you feel the cellular system encircling upwards from the lower legs. Here the energy and circulation moves upwards, whereas in Utthita Trikonasana you direct the energy to be firm on the feet. In Utthita Parsvakonasana you observe that the blood is flowing towards the knee from the bottom foot. Have you ever felt it? Observe Virabhadrasana I, here the blood circulates from the bottom of the knee towards the Pelvis. In Utthita Parsvakonasana, you feel the blood flowing upwards from the lower leg and backwards from the knee to the hip of the front leg. The moment you change to Virbhadrasana II, you feel the blood flowing on the back portion of the leg.

By correct performance with the range of asanas this way, the circulation of blood and the flow of energy in various directions in the leg increase and the entire leg gets cleansed. In Utthita Parsvakonasana, if you feel warmth in the outer leg but not in the inner leg, then the circulation is taking place only on the outside and not inside. When the circulation is balanced inside as well as outside, it means you are doing a healthy pose. This is cleanliness (sauca), which is implicit in asanas. Otherwise the blood does not reach from the flesh to the marrow; the inner leg cells do not receive nutrients and they die; only the outer cells get a supply and are kept healthy.
Varaha Upanisad speaks of ratna purita dhatu (the blood filled with jewels), a special constituent and essential ingredient of the blood in the body conveys that the quality of the blood should be brought to the level of a jewel. That is the effect of the asanas, which build up the cellular system as jewels, so that the body can take care of itself and the consciousness can attend to the higher aspects of life.
Take the example of AIDS. Scientific research has shown that the cellular system possesses its own intelligence and its own memory. It does not work with the dictates of the brain. It follows that yogic science works directly on the cells without the use of the brain. This is only possible if a thorough practice of asanas is maintained, continuously for the cells to look after themselves. That is why Patanjali advises not to discontinue practice. Even if one has experienced Samadhi, one may fall from that state of illumination. The cellular system needs discipline, toning, purification and sanctification through the practice of eight-petalled yoga.”


BKS Iyengar : Astadala Yogamala : Vol 1