Midday-Midnight Law

Chinese people believe that each of the twelve organ-meridian-function complex has a period of two hours during which its activity becomes maximum. Chinese took therapeutic advantage of this. Thus the liver has maximum activity from 1 A.M. to 3 A.M. and so any type of physiological, embryological or anatomical entities which occur during this period are grouped under liver . For e.g. Liver type of migraine.

This law can be used for diagnosis also. If a meridian is deficient, it should be treated during the period of maximum activity. If the meridian has excess, it should be treated after the period of maximum activity.

An exploratory study of the relationship between the midday-midnight law and electrical conduction properties of corresponding acupuncture points.Lee MS, Shin BC, Jeong DM.
Center for Integrative Medicine, Institute of Medical Science, Wonkwang University, Korea. drmslee@gmail.com

The midday-midnight law is a well-known empirical law in Oriental medicine stating that the circadian rhythm of internal organs influences their paired organs according to the time of day. However, there has been little research to test the purported relationship between the time of day and organ function. The purpose of this preliminary study was to investigate whether the midday-midnight law applies to the meridian activity and the electrical conduction properties of the acupuncture points. We used the digital readout instrument (MERIDIAN) to measure electrical conduction properties at 12 acupuncture points corresponding to the 12 meridians at four times: 12:00, 14:00, 22:00, and 24:00 hours. There were no significant differences in the electrical current values measured at the four times in any meridian. However, the mean current values of 12 acupuncture points changed significantly over time (P < 0.0001). The mean current values were significantly higher at 14:00 (P < 0.001), 22:00, and 24:00 hours (P < 0.001) than at 12:00 hours. The highest current value occurred at 22:00 hours and was significantly higher than 24:00 hours (P < 0.05). Although these do not conclusively support the traditional midday-midnight theory, our data suggest the existence of some type of daily variability in electrical current.

PMID: 16617688 [PubMed - indexed for MEDLINE]