The heart holds the office of lord and sovereign.
The radiance of the spirits stems from it.
That translation is from Claude Larre and Elisabeth Rochat, The Secret of the Spiritual Orchid. Often called the Inner Classic of Chinese Medicine, this 2000 year old text is referenced occasionally in the modern teaching of Chinese Medicine. It is used more often when teaching esoterica because it isn't all that specific.
The expression translated above as "radiance of the spirits," is actually a common martial arts term--mingshen.
Mingshen is mentioned in the taijiquan classics as the fruition of practice. I think it is what I see in a young student's eyes when they are ready and eager to learn. It is also that quality you see in a great fighter's eyes which is capable of ending the fight before it has even started.
Mencius said: If a ruler has mingshen, when he and his army invade a country, its people will lay down their arms and join him. Now that sounds like either a really good reputation or very potent shamanic prowess.
Descriptions of mingshen in the martial arts deal with perception, consciousness, proprioception, and kinesthetic awareness. These descriptions often sound mystical. Mingshen is the ability to wield forces that seem to be outside your body, outside your opponent's body too. This "space power" gives liveliness and dimensionality to our movement, it is the main subject of the highest level martial arts.
You can't really be a "modern" person and not ask the questions with regard to pre-20th century ideas, "What should I keep and what should I discard?" "What can I use, and what will just hold me back?"
Everyone has to answer these questions for themselves. Are useless acts good for the heart? Does extraordinary martial prowess have any real utility?
Hardly any country in the world has done as much discarding in the 20th century as China has. But it hasn't always been honest or well considered discarding. Now they are looking through the trash to see what can be salvaged.