The Three Treasures

They represent the three states of condensation of Qi.

Essence - Jing : It is the most material and in tradition it is compared to the Earth within the macrocosmos and in the body's microcosm it is equated with the Kidneys. It is the root of the body.
Energy - Qi : It rises above the earth and its manifestation in the physical world is visible through the body. It is equated with the human being or the Stomach and Spleen.
Spirit - Shen : Understood as the set of the five mental-spiritual activities of the human being, it is the most subtle and is compared to the Heaven and the Heart.

There is a relationship of interdependence among the three.

The illness and the three treasures

Qi is the most susceptible to being affected by daily changes in life, from one second to the next there can be significant variations.

To a certain extent, change is the natural state of Qi.
We can see the ease of change of Qi in the pulse.
Being exposed to an emotion, a flavor or a dominant organ for a long time is what causes illness, it is "unnatural". See: the causes of the illness

When a situation is maintained for a long time we say it begins to take root in the body, it affects Jing and manifests in Shen.

Thus, an emotional stress sustained for a long time weakens the Jing and disturbs the spirit.
The poor diet or eating the same thing always (little variety of ingredients, colors or flavors), for a long time, also weakens the essence.
Being exposed to a certain climate for a long time ends up exhausting the essence in the same way.
The weakness of the essence ends up affecting the mental-spiritual abilities and the person becomes agitated, life does not flow.

The three treasures must maintain a certain balance between natural change and order in life.

This is the way to maintain health:

Feed the body without rigidity.
Keep the constant movement of the energy.
Cultivate and stimulate the mind and spirit with a personal practice.