So if I’m understanding your question right, you’re basically asking about one of the many broad psychological and physical subjects which the concept of Yin-Yang symbolize in traditional Chinese culture. While this is kind of out of my field (I study gender and sexuality propaganda during the Republic of China/early PRC), it is relevant, and I’ll try to do my best to give an understanding of how Chinese scholars, particularly Daoists, viewed sexuality and it’s relation to human health.

So quickly, in case you’re unaware, Yin (阴)is the dark and by extension the feminine aspect of Chinese cosmology. It can symbolize many things, such as physical things like the moon or women, or it can symbolize concepts such as femininity or sinister actions. Yang (阳) on the other hand, is the light. It symbolizes physical concepts like the sun or men, and concepts such as masculinity or good nature. Naturally, as you can see, this doctrine is inherently sexist, and it plays a big role in sexuality in pre-modern (and post-modern) China.

Okay so, let’s talk about sex and moderation! Why was too much sex viewed as such an awful thing, while in the same respect too little sex was equally as rough for one’s health. Simply, because the Yin-yang is about self-moderation. Although, as I’ll discuss later there are also physical health concerns the ancient Chinese were aware of about the dangers of too much sex. Self-moderation and self-criticisms are key aspects in Confucian philosophy that are pervasive themes throughout Chinese history, but I won’t discuss the latter too much here, what we’re interested in is Self-moderation.

Too much sex was thought of as draining on a person’s yang (that ‘light,’ or good element). If one should lose their way, they will naturally become a worse person. It is important to understand that Daoists, unlike Confucians, believed that humans must become in tune with nature, that human nature is ‘good,’ and can be tamed through simplicity in lifestyle, while Confucians believed humans must maintain rigorous ritual in order to combat their ‘evil’ nature ( you can read more here- http://afe.easia.columbia.edu/special/china_1000bce_daoism.htm). So sex is a big part of human desire, perhaps the biggest, and it needs to be disciplined.

So the literature. Did these literati actually thing people could drop dead from sexual hedonism? Probably not. But it was a moral story for rulers. If a ruler spent too much of his time entertaining concubines and drinking wine, instead of ruling, the system that China was built on, those Confucian ritual relations in which the emperor is at the top, would (and sometimes did) fall apart. So think of these more as moral stories to attract attention against a person having too much sex.

Now, as I said before, chinese scholars understood the practical dangers of too much sex as well. Too much sex, as you’re aware, with so many people, can lead to veneral disease and other nasty things, especially in the pre-modern medicinal world! So there was a practical element to all this boring (or interesting!) cosmological beliefs. So yeah, too much (unprotected) sex can make you drop dead... eventually.

I found a neat article here on JSTOR if you’re interested in further reading or can access it: https://www.jstor.org/stable/3811786?seq=5#metadata_info_tab_contents

I hope this helps. Let me know if you have any more questions!