Static qigong, cross-legged sitting posture and blood redistribution

Static Qigong enables the cerebral cortex to enter the state of
relaxation and tranquilization from the state of catatonic excitement by regulating the mind, breathing and body, which reduces the excitability of the sympathetic nerve, slows down the adrenal and the secretary function of the adrenocortical hormone, while the excitability of the parasympathetic nerve can be raised. Thus, the capillaries are expanded to improve blood circulation. During one four-year's research, Shanghai Hypertension Research Institute repeatedly tested, from 2,114 cases, that Qigong exercises could increase the volume of blood flow of limbs and the cardiac index of the heart. Besides, the capacity of blood vessel of the fingertip could be raised to about 20%. Increasing the pulsating amplitude of rheoencephalogram could improve blood circulation of the brain.

The theory of Midnight-Noon-Ebb-Flow describes the sufficiency and deficiency of blood and Qi in acupoints similar to the ebb and flow of tide. Qigong practitioners advocate to training during the period of Zi or Wu in a day. Because from 11 p.m. to l a.m. (zi) is the time when Yang increases and Yin decreases. It's beneficial to Yang-Qi to train at this period. From 11 a. m. to 1 p.m. (wu) is the time when Yin increases and Yang decreases.

Qi is the commander of blood and blood is the mother of Qi. Qi propels blood forward. Therefore, where there is sufficient supply of blood, there is sufficiency of Qi. Take meditation for an example. After half an hour of leg-crossed posture, the color of the toenails and the skin of the lower limbs turn to dark brown. It indicates the blood circulation of the lower limbs slows down, and the blood flow is blocked to different degrees, but simultaneously, the blood supply to the trunk, upper limbs and head is more sufficient and the Qi is also cultured. Hence it suggests that one often takes leg-crossed sitting postures to keep fit and live longer.