There are six external pathogenic influences that can affect the body - wind, cold, fire, summer heat, damp and dryness. These pathogens enter through the weak and unprotected layers of the body and may cause disease in patients whose immune systems are weak. Theories about disease developed in areas of China where environmental influences were strong; for example, in areas where "warm" diseases were prevalent, usually in the south, practitioners developed herbal formulas and methods for treating conditions such as malaria and infectious diseases. Bell's palsy is seen more frequently in northern climates where wind and cold predominate, and so there are protocols for treating this condition.
As we head into winter, it's helpful to dress accordingly and shield yourself from the elements. Eating warming meals is a strategy for fortifying the body and digestive system against cold and damp weather.
Patients may not think about how the environment plays a role in health and disease, but the development of Chinese medical practices were built on observation of how the population was affected by external influences. Practitioners today are trained to look for those influences that may be adversely affecting their patients and suggest ways to counteract them - just another way of treating the patient in a holistic manner.