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TCM Physiology

Completion of Respiration Requires the Coordination of the Lungs and Kidneys

Traditional Chinese Medicine believes that the breathing process is primarily completed through the coordination of the "Lungs" and "Kidneys". The Lungs govern respiration, overseeing the diffusion and descending of Qi, inhaling clear Qi into the body and exhaling turbid Qi out of the body. The Kidneys govern the reception of Qi; "Reception" means securing, receiving, and drawing in. The Kidneys have the function of securing the clear Qi inhaled by the Lungs (the Qi from nature), preventing shallow breathing, and helping to maintain normal respiratory depth.

This principle can be summarized as:

• The Lungs are the master of Qi: The Lungs are the ruler of the breathing process, presiding over the process of respiration.
• The Kidneys are the root of Qi: The Kidneys are the source and foundation of respiratory Qi. Just like tree roots firmly grasp the soil (Qi), they make breathing deep and stable.

Kidney Essence and Kidney Yang are the Foundation for Kidney Function

• The Kidneys store Essence: The fundamental Essence of the human body is stored in the Kidneys. Essence can transform into Qi, producing "Kidney Qi". Sufficient Kidney Qi is the material basis for the Kidneys to perform the function of "receiving Qi".
• The warming and securing functions of Kidney Yang: Kidney Yang is like the furnace of the body, warming the Zang-Fu organs, including the Lungs. While helping the descending of Lung Qi, Kidney Yang itself has a "securing" function, which can firmly anchor Qi in the lower part of the body.

Under normal physiological conditions, when Kidney Qi is abundant and the Kidney's function of receiving Qi is sound, breathing is even and harmonious, the breath is deep, and the inhaled clear Qi can smoothly reach the Kidneys and spread throughout the body.

TCM Pathology

When Kidney function is deficient, especially in cases of Kidney Qi Deficiency or Kidney Yang Deficiency, the securing ability declines, making it unable to effectively receive Lung Qi. This leads to the rebellion of Lung Qi upward, preventing the maintenance of breathing depth, resulting in the pathological state of "Kidney Failing to Receive Qi".

Clinical manifestations:

• Shallow breathing, less exhalation and less inhalation: The patient feels difficulty inhaling, as if the breath cannot reach the bottom, stopping at the throat or chest.
• Dyspnea on exertion: Breathing might be barely maintained at rest. However, with any activity (like walking, climbing stairs), when the body's oxygen consumption increases and deeper breathing is required, the Kidney's inability to receive Qi becomes immediately apparent, leading to panting and shortness of breath.
• Systemic symptoms accompanying Kidney Deficiency:
  • Kidney Qi Deficiency: Accompanied by soreness and weakness of the lower back and knees, mental fatigue and lack of strength, tinnitus, frequent urination or clear profuse urine, pale tongue with white coating, deep and weak pulse.
  • Kidney Yang Deficiency: Symptoms of Kidney Qi Deficiency, plus signs of deficiency-cold such as aversion to cold and cold limbs, pale complexion, frequent nocturia, edema of the lower limbs, etc.

Common diseases:

• Chronic Obstructive Pulmonary Disease (COPD), Emphysema, remission or late stage of Bronchial Asthma: These patients often exhibit long-term dyspnea that worsens with exertion, which in TCM pattern differentiation mostly belongs to "Kidney Failing to Receive Qi".
• Chronic cough or asthma where prolonged illness affects the Kidneys: Long-term coughing can consume and damage Lung Qi. Prolonged deficiency of Lung Qi can affect the Kidneys, leading to deficiency of Kidney Qi, eventually forming "Kidney Failing to Receive Qi".
• Decline of respiratory function in the elderly and those with weak constitution: As age increases, Kidney Qi naturally declines, and the function of receiving Qi weakens. Therefore, the elderly often exhibit shallow and rapid breathing.

Integration with Modern Medicine

According to modern physiology, the primary purpose of pulmonary respiration is to inhale oxygen and exhale carbon dioxide. However, the lungs do not dictate the destination of oxygen; the ultimate goal of oxygen is almost always the mitochondria within cells. Mitochondria use oxygen to oxidize glucose and produce energy (ATP). Where should this fundamental, systemic physiological fact be placed within the theoretical system of TCM? The answer likely lies in "The Kidneys Govern the Reception of Qi"—that is, the mitochondria receive oxygen for oxidative energy production, and the energy produced forms part of the basis of "Kidney Yang".

Respiration requires the concerted effort of all the Zang-Fu organs, and "respiratory depth" also relates to the synergistic action of the respiratory muscles:

• If the Heart is weak, Qi and blood cannot be effectively distributed, the gas exchange ability of the Lungs is poor, and the respiratory muscles do not receive sufficient nourishment from Qi and blood, then breathing becomes shallow.
• The Spleen governs the muscles and is the source of Qi and blood production. If the Spleen is deficient, then the Heart, Lungs, and respiratory muscles all fail to receive sufficient nourishment from Qi and blood, leading to shallow breathing.
• The Liver governs the tendons, controls free coursing, and regulates the mechanism of Qi. Liver Qi Stagnation or rebellion can also affect the diffusion and descending functions of the Lungs, leading to chest tightness and panting.
• The Kidneys govern the two lower orifices (urination and defecation). If the Kidneys are deficient, urination is weak, water metabolism is impaired leading to edema, which in severe cases can affect heart and lung function, causing breathing to become shallow.

In other words, shallow breathing alone does not fully reveal the importance of the role the Kidneys play here.

Seeking the essence through the phenomena: Most patients with shallow breathing suffer from prolonged illness, chronic diseases, or are elderly and physically weak. The essence of their insufficiently deep breathing and weak respiratory muscles is not solely due to weakness of the Heart, Lungs, Liver, or Spleen, but is actually respiratory weakness caused by "systemic energy depletion". The essence of systemic energy depletion, most directly related to "receiving Qi", lies in the inefficient uptake of oxygen by mitochondria and their oxidative energy production. ATP is the fundamental energy source for the entire body. Insufficient ATP leads to a drop in body temperature, resulting in shortness of breath. This can be seen as part of the substance of "Kidney Failing to Receive Qi" and "Decline of Kidney Yang".

The "Kidneys" in TCM represent a collection of physiological functions with similar attributes. Linking "The Kidneys Govern the Reception of Qi" to mitochondrial oxygen uptake and energy production does not mean encompassing all other functions of the Kidneys within this concept. This article only proposes a reasonable hypothesis regarding the part of "The Kidneys Govern the Reception of Qi". After all, mitochondrial oxygen uptake and energy production is an ironclad fact. It is not a local phenomenon but systemic throughout the body, which does not conflict with the systemic concept of the Kidneys in TCM.