In his book Autobiography of a Yogi, Paramahansa Yogananda describes the ability of various yoga practitioners to extend the capacities of the body far beyond what we consider to be normal, including prolonging the life span dramatically. One example he described was of Babaji, a yogi who reportedly lived and acted in the world for hundreds of years. This example was not an isolated case, as other yogis have been reported to extend life span or cure disease. Sri Aurobindo related a tale about his brother who at one point was desperately ill. A wandering yogi chanted mantras over a glass of water and was able to cure the sick man of the fever. Sri Aurobindo related this to remark on how he came to understand the power of yoga to effect change in the world, and helped shift him from his political focus to take up the spiritual direction to which he dedicated the balance of his lifetime.
Modern science itself has seen remarkable achievements in terms of extending the normal lifespan of humanity. Just a few hundred years ago, most people in Europe died by their 40’s. Today the average life span is approximately 80 years. Advances in understanding of the needs of the body, nutrition, hygiene, basic principles of managing sewage, along with advances in vaccines, pharmaceuticals, surgery and management of diet and lifestyle all contribute to this lengthening lifespan. Theoretically, these external measures can still add numerous years to the life.
As the next evolutionary phase becomes operational, it will provide new power and knowledge to the very cells of the body to help them adjust and respond to pressures and thus, remain integrated and coherent as a unified body that can withstand far more pressure without breakdown than we can currently bear.
Sri Aurobindo notes: “The change of the consciousness is the necessary thing and without it there can be no physical siddhi. But the fullness of the supramental change is not possible, if the body remains as it is, a slave of death, disease, decay, pain, unconsciousness and all the other results of the ignorance. If these are to remain the descent of the supramental is hardly necessary — for a change of consciousness which would bring mental-spiritual union with the Divine, the overmind is sufficient, even the Higher Mind is sufficient. The supramental descent is necessary for a dynamic action of the Truth in mind, vital and body. This would imply as a final result the disappearance of the unconsciousness of the body; it would no longer be subject to decay and disease. That would mean that it would not be subject to the ordinary processes by which death comes. If a change of body had to be made, it would have to be by the will of the inhabitant. This (not an obligation to live 3000 years, for that too would be a bondage) would be the essence of physical immortality. Still, if one wanted to live 1000 years or more, then supposing one had the complete siddhi, it should not be impossible.”
“There can be no immortality of the body without supramentalisation; the potentiality is there in the yogic force and yogis can live for 200 or 300 years or more, but there can be no real principle of it without the supramental.”
“Even Science believes that one day death may be conquered by physical means and its reasonings are perfectly sound. There is no reason why the supramental Force should not do it. Forms on earth do not last (they do in other planes) because these forms are too rigid to grow expressing the progress of the spirit. If they become plastic enough to do that there is no reason why they should not last.”
Sri Aurobindo, Integral Yoga: Sri Aurobindo’s Teaching and Method of Practice, Chapter 8, The Triple Transformation: Psychic, Spiritual and Supramental, The Supramental Transformation, pp. 229-237