The LA (bla) is a physical element related to a person's vital force which makes the link with the external world. It is luminous and it moves in the body in a lunar monthly cycle. When it is unimpaired, it says within the body and includes the protective forces of the individual.

Although it is attached to the human body, the LA can also have an external substratum to which the person's life is thereon tied. It could be a hill, a mountain, a tree, a lake or even stone like a life turquoise. It such a case, the individual LA connects with the LhA or local deity. Among other reasons, this is why in Tibet men have always maintained a harmonious relationship with their environment: since the vital energy is bound to the external LA forces, defiling or destructing their abode is tantamount to endangering the individual's life itself.

When the life forces weaken or when one faints or collapses, the LA can break away from the body and roam the external world. It can then also be lured and taken away by damsi (devils) -- this is considered as a case of possession -- or attacked whit black magic practises -- this is seen as spell throwing. In such a case, the person is exhausted, affected by illness, and if appropriate practises are not performed to end this situation, it is said one cannot survive more than six months. After death, the LA can linger on somewhere -- for example at the grave; it cannot incarnate again, but it can visit the living.

According to the Kalachakra Teaching, the movement of LA occurs in the left part of the body in men, and in the right part in women. At the first day of the lunar month, the LA is located at the soles of the feet, and during the lunar month, it proceeds in the shape of a bright letter throughout the body, until it returns to its initial location.

It is considered the the LA is predominantly found in specific body locations at different periods of the day, and it is thus said that: "at dawn the LA dwells in the bladder, at sunrise in the neck, in the morning it is at the lips and nape, at noon it is in the chest and ribs, in the afternoon it is in the abdomen, in the evening it is in the heart, at sunset in the back, and from nightfall to sunrise in the whole of the body".

According to Tibetan Medicine, it is very important to avoid wounding, bleeding, cauterizing or otherwise operating a body part whilw it is the location of LA, as this could shorten and even destroy life. It is therefore recommended to respect tho monthly cycle of LA according to the lunar calendar, so as to avoid loss of vital energy even in the course of minor operations.