One of the most central concepts of TCM is that of the intimate connection between the body and the environment. The physiology of the cells, tissues, zang-fu organs and meridian system of the body is in dynamic internal equilibrium and constantly adjusts to the vagaries of the external environment. If the body is not able to cope with changes in the environment, internal equilibrium will be lost and disease will result. Thus, according to the constitution of any particular individual, the presence of disease is due to a lack of adaptability by the physiology of that individual to the conditions of the environment.
By Marcus Quigmire from Florida, USA (Just Wings) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons