What Sustains the Rūpa Body in the Four Dhyānas?

When one cultivates to the state of the fourth dhyana, what phenomena occur in the body? Originally, we rely on the mouth and nose for breathing, but now breathing ceases. Not only does breathing stop, but the beating of the heart and pulse also stops, and all phenomena of qi and blood circulation cease. What function do the heart and pulse serve? With each contraction and expansion of the heart, blood is transported throughout the body to nourish it. For the body to function normally, it requires qi and blood; qi drives the blood to circulate continuously throughout the body. Blood is the nutrient, the nourishment required by the body as a machine. Without nourishment, the machine cannot function. Under normal circumstances, the faster this bodily machine operates, the more nutrients it requires, and the more qi and blood it needs. This demands a more robust heart function to ensure the body's normal operation. These qi and blood represent the Four Great Elements required by the body, which are composed of the Four Great Elements.

When the dhyana is very deep, the body's operation slows down, the internal organs consume fewer nutrients, and less qi and blood are needed. When the body consumes nutrients at a minimal level, metabolism slows, and the Four Great Elements are no longer required in large quantities, breathing ceases, and the beating of the heart and pulse stops. However, a small amount of qi and blood is still necessary to sustain the existence and operation of the life form, except that it no longer relies on coarse nourishment from breathing, eating, and drinking. The body's pores absorb the subtle particles of the Four Great Elements from the surrounding air, which is sufficient. Waste from the body is also expelled through the pores. If a person in deep dhyana is placed in a sealed container, they will suffocate and die due to the lack of the Four Great Elements supplied by the air.
The material body is also composed of the Four Great Elements. The material body and the surrounding environment are interconnected and mutually influential; matter can also exchange particles of the Four Great Elements with one another. Therefore, the material Four Great Elements continuously radiate outward and have a mutual influence. In other words, external matter can transmit these material particles through every cell of the body, which are then absorbed and become part of the body's substance. Simultaneously, the body's substance also emits particles of the Four Great Elements outward. When this input and output reach a state of balance, the body functions normally. The material body can absorb the Four Great Elements from the external environment to sustain its operation; thus, the external material environment can influence the material body. Similarly, the body's Four Great Elements also radiate outward, so the body can influence the external material environment. Therefore, there is a certain connection between sentient beings' bodies, and they can influence each other. Let us tentatively call this phenomenon collective karma.

After beings in the desire realm enter the fourth dhyana, their bodies rely on the surrounding environment for nourishment. Beings in the form realm in dhyana also rely on subtle Four Great Elements for nourishment. Beings in the formless realm have no material body and thus do not require nourishment from the material Four Great Elements. Without dhyana, the body consumes a great amount of the Four Great Elements. The more bodily and mental activities there are, the more the Four Great Elements are consumed, and the more qi and blood are needed. People with many distracting thoughts consume more qi and blood and need to eat more than others. Those with fewer distracting thoughts consume less, and those with less bodily activity also consume less.

We should regard the material body as a machine; indeed, it is a machine. The operation of this machine consumes nourishment. For it to function normally, it must be supplied with sufficient nourishment. The faster the machine operates and the greater the workload, the more nourishment and energy it requires. The energy humans need comes from food and the material living environment; machines need lubricating oil to operate. If you want this machine to have a long lifespan, you must reduce its operation and workload. Because when the machine operates, there is wear and tear; it consumes the machine. The more it operates, the more it wears out, and the machine gradually becomes old, with various functions declining. It is the same for humans: the greater the physical activity, the more the human body, as a machine, wears out, and the shorter the lifespan will be.

In dhyana, a person has very few distracting thoughts or none at all, and the body is inactive. They need less nourishment, their internal organs are less active, and there is less wear and tear. People with dhyana generally have healthy material bodies and live long lives. Modern people do not understand this; they emphasize living well, eating well, and having fun, enjoying food without realizing that the more they eat and the higher the nutritional value, the greater the workload for their internal organs, the more severe the wear and tear, and thus the worse the body becomes and the harder it is to live long. Therefore, eating more and consuming high-nutrition foods makes it very difficult for the internal organs to digest and absorb, requiring a tremendous workload. The internal organs consume heavily, making longevity difficult. To live long, one must reduce bodily wear and tear, decrease workload and physical activity, and cultivate more dhyana to reduce distracting thoughts.

Dhyana calms the mind; both mental and physical activities are reduced, wear and tear are minimized, and thus lifespan is extended. After attaining the fourth dhyana, the length of life is determined by oneself. If one wishes to relinquish life early to go to another world, such as a heavenly realm, it is up to oneself. If one does not wish to relinquish life early or wishes to live for a thousand or ten thousand years, it is also up to oneself, because within the fourth dhyana, there are supernatural powers that allow free mastery over the body's stay or departure; the timing of life and death is self-determined. However, one is not yet completely free because the view of self has not been severed; one cannot escape the six realms of rebirth. Only the life and death of this present life are under one's control. Without the fourth dhyana, one is not free regarding life and death in this world. To relinquish life early, one must resort to suicide. Wishing to live an extra year, half a year, a day, or an hour is not up to you.

The body is merely an instrument for our cultivation. View it objectively, regulate it well, but do not cling to it or regard it as self or belonging to self. Then, we can use the body well for spiritual practice, at the very least preventing it from becoming a burden that drags us into endless cycles of birth and death.