The Six Qi — six natural climate factors, — are Wind, Cold, Summer Heat, Damp, Dry, and Fire or Heat (Fire). Generally, humans adapt to gradual and progressive climate changes, but diseases may occur when the body is unable to adapt. Normal climate change may be pathogenic for those with a deficient constitution or decreased adaptability. However, an abnormal climate change may be pathogenic for most people.
The six pathogenic-factor-induced diseases have the following characteristics:
Disease susceptibility is related to seasonal climates or the living environment:
- Wind in spring.
- Cold in winter.
- Summer Heat in summer and early autumn.
- Damp with a prolonged stay in a wet area.
- Dry in autumn.
- Heat (Fire) with a prolonged stay in a hot area, which is the predominant climatic factor in summer. Heat and Fire are often mentioned in the same breath; Heat is the manifestation of Fire, and Fire is the nature of Heat. They may mean a certain degree, different from each other but intrinsically related to each other.
The six pathogens may invade individually or in combination. For example, Wind may invade with Cold, Damp, Dry, Heat, etc., to respectively induce:
- Wind-Cold syndrome.
- Wind-Damp syndrome.
- Wind-Dry syndrome.
- Wind-Heat syndrome and other syndromes.
The six pathogens may induce primary symptoms but then progress due to individual differences in constitution and pathogen sensitivity. For example:
- External Cold, after invading the body, may turn into Heat.
- Damp, after staying in the body for a long time, may turn into Heat.
Some pathogens induce different diseases due to individual constitutional differences. These phenomena are called “Secondary transformations.” For example:
- External pathogens may transform into Heat in Yang-excess or Yin-deficient bodies.
- External pathogens may transform into Cold in Yin-excess or Yang-deficient bodies.
- External pathogens may transform into Damp in Damp-excess or Spleen-deficient bodies.
The six climate change pathogens often induce five inner pathogens which relate to dysfunction of internal organs. The six pathogens generally invade the Lung through the mouth and nose, or the body interior through the skin. Exterior syndromes may arise first, followed by interior syndromes. These five pathological changes include:
- Inner Wind, where external Wind may induce inner Wind.
- Inner Damp, where external Damp may induce inner Damp.
- Inner Cold.
- Inner Dry.
- Inner Heat (Fire).