As far as I know, it is Mr. Ma Litang who created and popularized the six-character formula of health preservation. As early as 1984, it was introduced into China Qigong. The pronunciation of these six words is the pronunciation of this word. You can search Ma Litang's six-character formula on Baidu. There is a video of Ma Lao's daughter doing a demonstration on it, which is slightly different from that introduced in Ma Lao Qigong magazine. You can go and have a look.