The Relationship between Meditative Concentration and Underlying 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 reduce the manas's grasping, decrease the activity of the physical body, and lessen the stirring and control of the entire nervous system, so that the brain and nervous system, the five internal organs and six viscera, and the whole body all move and consume the four great elements less; the body then does not fatigue, and the manas need not decide on sleep.

The deeper the meditative concentration, the less sleep is needed—to the point where one can completely cease sleeping. Because at that time the manas is very quiet, no longer wishing to engage in any activity, it no longer excessively mobilizes the brain and 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 it regulates and controls, the less it consumes of the four great elements, and the less it needs sleep and food.

Some people, in their daily work, do a great deal of work yet have very few mental thoughts; they consume less, 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's mental thoughts decrease, the amount of activity diminishes, and the work no longer feels tiring.

It can be seen that the manas can grasp and understand the condition of the physical body anytime and anywhere, and can regulate, control, and direct it anytime and anywhere. He discerns with great keenness; the mind consciousness does not even know the various conditions of the body, and still requires the manas's hints and alerts.