The Relationship Between Meditative Concentration and Latent Tendencies

When there is meditative concentration (samādhi), one needs less sleep, and the body does not require too much sleep. This is because meditative concentration itself can reduce the activity of the six consciousnesses, lessening the consumption of the four great elements' nourishment. Meditative concentration can also cause the manas to engage in less grasping, reducing the activity of the physical body, lessening its pulling on and control of the body's entire nervous system. The brain's nervous system, the five internal organs and six viscera, and the whole body can then move and consume the four great elements less, so the body does not become fatigued, and the manas need not decide on sleep.

The deeper the meditative concentration, the less sleep is needed—so much so that one can entirely cease sleeping. This is because at that time the manas is very quiet, no longer inclined toward any kind of activity, and thus no longer excessively mobilizes the brain's nervous system; there is very little activity of the body faculty and very little activity of the conscious mind. The more concentrated the manas, the less it grasps, the less regulatory activity there is, the less the four great elements are consumed, and the less one needs sleep and food.

Some people, in their daily work, do a great deal of work yet have very few mental thoughts, so their consumption is low; they do not need to eat so much food, do not need so much sleep, and still remain full of energy. This shows that what consumes the energy of the four great elements the most is the mental activity of the manas, while the six consciousnesses themselves do not consume very much. Therefore, even though the workload of the six consciousnesses is not reduced in the slightest, when the manas has fewer thoughts, the amount of activity decreases, and the work no longer feels tiring.

From this we can see that the manas can grasp and understand the condition of the physical body at any time and place, and can regulate and direct it at any time and place. He discerns with great keenness; the mind consciousness does not even know the various conditions of the body, and still requires the manas to hint and alert it.