It is important to build up a strong immune system prior to the cold and flu season. Regular exercise, short cold shower following a hot shower, and ingestion of tonic herbs are all beneficial to strengthen the body and its immune system. Adequate rest is essential for recovery. Avoid exposure to wind by putting on more clothing. Covering the head and neck area is especially important. Fluctuation of temperature increases the risk of bacterial and viral infection. Installation of an air purifier is recommended for patients who repeatedly catch infectious respiratory disorders.