Does Utilizing Manas for Buddha-Recitation and Contemplating Issues Induce Fatigue?

When reciting the Buddha's name, simply recite without engaging the intellect to ponder the various virtues of the Buddha or questions about how to recite effectively to achieve results. This consumes relatively little mental effort and energy. If the duration of recitation is not too long and one eats normally, fatigue is unlikely to be felt. However, when initially learning to recite with the manas (mental faculty), due to lack of proficiency, it requires some mental exertion and may feel more tiring. Once the recitation gradually enters the state of samadhi, with deeper meditative concentration, good circulation of qi and blood, and sufficient nourishment and energy, the feeling of fatigue disappears. Instead, the physical body becomes light and at ease, and the spirit feels joyful. In the state of samadhi, energy consumption is extremely low.

Using the manas to contemplate issues differs from reciting the Buddha's name. Contemplating problems requires mental exertion, consuming more mental effort and energy. Without an ample supply of energy, fatigue sets in. During Chan meditation, the primary activity is the investigation and deliberation of the manas, which requires mobilizing the nervous system. With higher energy consumption, it feels very tiring. Therefore, those who practice Chan meditation tend to eat more, just as people who use their brains heavily consume more food and need to rest periodically; otherwise, they feel exhausted. However, if one enters very deep meditative concentration, where qi and blood are abundant, energy can be replenished adequately, making fatigue less likely. Shallow meditative concentration, on the other hand, easily leads to tiredness. If Chan meditation reaches a deep state of samadhi, where qi and blood circulate well, and the body and mind are light, at ease, and joyful, then fatigue is no longer felt.

Using the manas for deliberation consumes more energy, while using the consciousness (mano-vijnana) to think about problems consumes less. This is because the deliberation of the manas requires engaging the brain's nervous system, which consumes energy and thus causes fatigue. The entire nervous system is mobilized by the manas; the consciousness cannot mobilize it. Therefore, thinking with the consciousness is relatively effortless. Even if the mind is very scattered, thinking about everything, it does not feel particularly tiring. Many people prefer to use the consciousness and are unwilling to engage in deep contemplation and investigation.