Dealing with the heat radiation that comes from the sun is a matter of gaining the ability to absorb and utilize the energy without being overwhelmed by its force. Turning then to the issue of how to deal with cold, we have an entirely different scenario, in that we have a reduction in the energy available to us to absorb heat. Cold represents a lack of force, rather than an active force in its own right.
Nevertheless, it is useful, and important, to be able to determine how the body can effectively respond to cold. The normal reaction is an attempt to shrink in and close off the body from the impact of the cold, and in particular, to protect the body core. Obviously shelter, clothing and external heat generation are mechanisms we utilize, but this is not the answer to the question raised by the disciple to which the Mother responded.
The famous escape artist Harry Houdini reported that he systematically trained his body to bear the cold by bathing in ice and eventually he used this capability as part of his career. In this case, he habituated the body to respond to cold and accept it rather than try to escape it or protect against it through external means.
The Tibetan tradition describes a practice known by the name of tummo, which is a form of meditation practice which utilizes pranayama and visualisation. Advanced practitioners are able to withstand extreme cold, and Western scientists, studying the phenomena, have validated the increase in body heat by skilled practitioners of this method.
The great Tibetan yogi, Milarepa, is said to have utilized ttummo as part of his spiritual practice. It is noted that he spent long periods of time in the Himalayan mountains meditating without apparently suffering the cold of the caves he was frequenting.
A well-known French traveler, author and Tibetan Buddhist practitioner, Madame Alexandra David-Neel, described her initiation and development in the practice of tummo, and her subsequent ability to withstand extreme cold.
We thus see several different techniques, one through habituation, the other through active generation of internal heat, used by people seeking to mitigate the impact of cold on the body. In neither case, is the individual burdened by feeling like he is suffering from the cold.
A disciple asks: “Can one do the same thing when it is cold?”
The Mother answers: “Yes, I think so. I think one can always do the same thing in all cases.”
“The sun is a very powerful symbol in the organisation of Nature. So it is not altogether the same thing; it possesses in itself an extraordinary condensation of energy. Cold seems to me a more negative thing: it is an absence of something. But in any case, if one knows how to enter the rhythm of the movements of Nature, one avoids many discomforts. What makes men suffer, what disturbs the balance of the body is a narrowness, it is always a narrowness. It happens because one is shut up in limits, and so there is, as Sri Aurobindo writes here, a force which presses too strongly for these limits — it upsets everything.”
Sri Aurobindo and the Mother, The Hidden Forces of Life, Ch. 4 Cosmic and Universal Forces, pp. 92-93
Sri Aurobindo Studies 