WaiYin, or external causes, named after climatic conditions, are one of the most difficult concepts for a neophyte to grasp. Let’s just say that at the outset, the external causes are natural or artificial characteristics of the environment (cold, drought, humidity, heatwave, etc.) which fail the adaptation capacities of an organism whose defenses are weakened. .

These causes include as much waiting for the bus for 35 minutes at -30 ° C as working year-round in a cold store; as much a stay in a very dry environment as in a poorly ventilated workshop; as much the occupation of a humid basement affected by mold as the work in the rice fields. But beyond these familiar phenomena, climatic causes take on a broader meaning that we are going to define by placing TCM in its philosophical context that is 3 years old.

By observing nature, the Chinese associated specific qualities with certain natural phenomena. Thus, by noting that the water freezes under the effect of cold, they deduced that it has the quality of slowing down movement. Conversely, they concluded that heat stimulates movement, since water boils under its influence. While observing the sick, they noticed innumerable analogies between the ailments and these same phenomena. For example, by observing that elderly people had difficulty moving, that their fingers were frozen, that their pains were relieved by heat and worsened by cold, they deduced that they were affected by Cold – Western medicine will say that they have rheumatism. Through constant observation, TCM has concluded that the GLOSS microcosm of humans behaves in the same way as the GLOSS macrocosm of nature.

TCM has identified five main factors, called climates, which affect humans or represent specific types of conditions. Each of them is the subject of a more detailed sheet at the next level. It’s about :

• Du Vent (Feng). LINK N5
• Cold (Han). LINK N5
• Heat (Re). LINK N5
• Moisture (Shi). LINK N5
• From Drought (Zao). LINK N5

In its study of the causes of diseases, TCM has greatly refined the characteristics of these five elementary climates by providing them with all kinds of nuances: each can be combined with others, be qualified as internal or external, be in excess or lack, possessing too much Yin or Yang, coming from or affecting a particular Viscera, etc.

Even though Climates are considered to be external causes, they can be generated inside the body itself. This is why TCM talks about external and internal climates. In general, Climates are perceived as external pathogenic factors when they are linked to environmental conditions and seasons. Wind, cold, heat, humidity and drought are normal climatic elements to which our body usually adapts without problems. They become pathogenic if they vary abruptly or abnormally, or if our capacity for adaptation or resistance is weak; the Climates are then called external GLOSS perverse energies, since they attack the body and produce diseases.

On the other hand, if an individual presents symptoms corresponding to a certain climatic factor without having been in contact with it, we will say that he is struggling with an internal climate since he will have produced it himself in his organism. Indeed, TCM considers that each Organ can generate, inside the body, an imbalance similar to that which Climates produce on the environment.