According to Traditional Chinese medicine the Lungs function to purify inhaled air, produce defensive Qi, activate the flow of Qi downward, and maintain water metabolism.
-Purifying inhaled air
The most important, and perhaps most apparent, function of the Lungs is to extract clean Qi from inhaled air. This purified essence of the air is combined with food essence from the Spleen, and sent it to the Heart where it becomes blood.
–Producing Defensive Qi
The Lungs produce the very important Wei Qi, or Defensive Qi, which is the body’s first line of defense against pathogens from the environment. Wei Qi is closely related to the health of the skin and water metabolism (see below), particularly the opening and closing of the skin’s pores. When Defensive Qi is weak, the body easily succumbs to attack from external pathogens, such as parasites and infectious pathogens.
– Activating the flow of Qi downward
Because the Lungs are the uppermost organs in the body, their Qi must descend. When it is not descending, such symptoms as coughing, asthmatic breathing, and stuffiness in the chest can occur. It can also cause shortness of breath, tiredness and drowsiness.
– Maintaining normal water metabolism
When the Lungs are functioning properly, inhalation will send water downward to the Kidney and Urinary Bladder. Failure of the water supply to these organs can result in dysuria (inability to urinate), edema (swelling), and/or phlegm-retention conditions.
The Lungs are also responsible for supplying the skin and hair with the body fluid they need to stay moist and bright. By spreading Qi between the muscles and the skin, the Lungs regulate the opening and closing of the skin’s pores and keep the muscles warm. As part of the immune system, healthy skin defends the body from outside pathogenic factors. Unhealthy skin is associated with symptoms such as profuse sweating and vulnerability to the common cold.