II. Cold and Heat
Cold and heat are the two fundamental principles for distinguishing the nature of diseases. Cold syndromes and heat syndromes reflect the excess and deficiency of Yin and Yang in the body. Excess Yin or deficiency Yang manifests as cold syndromes;excess Yang or deficiency Yin manifests as heat syndromes. The “Su Wen: On the Correspondence of Yin and Yang” states: “If Yang is dominant, there is heat; if Yin is dominant, there is cold.” The “Su Wen: On Regulating the Menstrual Cycle” states: “If Yang is deficient, there is external cold; if Yin is deficient, there is internal heat.” This conveys the same meaning. Zhang Jingyue believes that “cold and heat are transformations of Yin and Yang.” In differentiating cold and heat syndromes, one should not make judgments based solely on individual symptoms, but rather through the four examinations to summarize the various symptoms and signs reflected by the disease itself.
Specifically, heat syndromes refer to a group of symptoms and signs characterized by heat manifestations; cold syndromes refer to a group of symptoms and signs characterized by cold manifestations. For example: in the case of exterior cold syndrome, symptoms include fever, severe aversion to cold, a pale tongue with a thin white coating, and a floating tight pulse, indicating a diagnosis of exterior cold syndrome; in the case of exterior heat syndrome, symptoms include mild aversion to cold, severe fever, slight thirst, a red tongue with a thin yellow coating, and a floating rapid pulse, indicating a diagnosis of exterior heat syndrome. It is important to note that aversion to cold and fever are different from cold and heat syndromes.
The differentiation of cold and heat syndromes is of great significance in treatment. The “Su Wen: On the True Essentials” states: “Cold should be treated with heat” and “Heat should be treated with cold“; this means that cold syndromes require warming agents, while heat syndromes require cooling agents, and the treatment methods for the two are entirely different.
1. Cold Syndromes
Cold syndromes are symptoms resulting from the invasion of cold pathogens or the excess of Yin and deficiency of Yang. They are often caused by external invasion of cold pathogens, prolonged internal injury, depletion of Yang Qi, or excessive consumption of cold foods, leading to internal accumulation of cold. Cold syndromes include exterior cold, interior cold, deficiency cold, and excess cold.
Clinical manifestations include: various cold syndrome symptoms may not be entirely consistent, but common ones include: aversion to cold with a preference for warmth, pale complexion, cold limbs, fatigue, a pale tongue with a white and moist coating, and a slow or tight pulse.
Syndrome analysis: Insufficient Yang Qi or damage from external pathogens fails to exert its warming effect, resulting in cold body and limbs, fatigue, and pale complexion; internal accumulation of Yin cold does not harm fluids, hence the preference for warmth and lack of thirst; Yang deficiency fails to transform fluids, leading to clear and cold secretions such as phlegm, saliva, and urine. Cold pathogens harm the spleen, or prolonged deficiency of spleen Yang leads to impaired transformation, resulting in loose stools. Insufficient Yang fails to transform, and internal dampness arises, leading to a pale tongue with a white and moist coating. Weak Yang Qi fails to promote blood circulation, hence the slow pulse; cold constricts, and exposure to cold causes the pulse to become tight.
2. Heat Syndromes
Heat syndromes are symptoms resulting from the invasion of heat pathogens or the excess of Yang and deficiency of Yin, characterized by hyperactivity of bodily functions. They are often caused by external invasion of fire heat pathogens, or cold pathogens transforming into heat internally; or excessive emotional stress leading to heat; or irregular diet leading to heat accumulation; or sexual overexertion depleting Yin essence, resulting in deficiency of Yin and excess of Yang. Heat syndromes include exterior heat, interior heat, deficiency heat, and excess heat.
Clinical manifestations: Various heat syndrome symptoms may not be entirely consistent, but common ones include: aversion to heat with a preference for coolness, thirst with a preference for cold drinks, red face and eyes, restlessness, yellow and thick phlegm and nasal discharge, hemoptysis, short and red urine, dry and hard stools, red tongue with a yellow and dry coating, and a rapid pulse.
Syndrome analysis: Internal heat predominates, leading to aversion to heat and preference for coolness. Severe heat damages Yin, depleting fluids, hence short and red urine; depletion of fluids leads to thirst for cold drinks. Fire rises, causing red face and eyes. Heat disturbs the mind, leading to restlessness. Heat damages fluids, resulting in yellow and thick secretions. Fire heat injures blood vessels, causing hemoptysis. Intestinal heat and fluid depletion lead to constipation. A red tongue with a yellow coating and a rapid pulse are signs of heat.
3. Key Points in Differentiating Cold and Heat Syndromes
To differentiate between cold and heat syndromes, one should not make judgments based solely on a single symptom, but should conduct a comprehensive examination of all manifestations of the disease, especially the preferences and aversions to cold and heat, thirst or lack thereof, complexion (red or pale), temperature of the limbs, urination, stool, tongue appearance, and pulse. The “Medical Insights: Differentiating Cold and Heat, Deficiency and Excess, Exterior and Interior, Yin and Yang” states: “In a disease, the differentiation of cold and heat is entirely based on thirst or lack of thirst; whether water is consumed or not; preference for hot or cold food; restlessness or cold extremities; frequency and color of urination; consistency of stools; and the pulse being slow or rapid. If there is thirst and the ability to consume water, preference for cold food, restlessness, short and red urination, and constipation with a rapid pulse, this indicates heat. If there is no thirst or false thirst with an inability to consume water, preference for hot soup, cold extremities, clear and long urination, loose stools, and a slow pulse, this indicates cold.“
4. The Relationship Between Cold and Heat Syndromes
Although cold and heat syndromes have essential differences in the excess and deficiency of Yin and Yang, they are also interconnected. They can appear simultaneously in a patient, manifesting as mixed cold and heat symptoms; they can also transform into each other under certain conditions, with cold syndromes transforming into heat and heat syndromes transforming into cold. During the progression of a disease, especially in critical stages, false appearances may also occur.
4.1 Mixed Cold and Heat
There can be upper heat and lower cold, upper cold and lower heat, exterior cold and interior heat, and exterior heat and interior cold.
(1) Upper Heat and Lower Cold: The patient presents with heat in the upper body and cold in the lower body simultaneously. For example, there may be symptoms of upper heat such as restlessness and frequent vomiting, along with lower cold symptoms such as abdominal pain with a preference for warmth and loose stools, which belong to this category of disease.
(2) Upper Cold and Lower Heat: The patient presents with cold in the upper body and heat in the lower body simultaneously. For example, there may be cold pain in the stomach, vomiting clear saliva, while also experiencing frequent urination, painful urination, and short red urine. This indicates cold in the stomach and heat in the bladder. The “Complete Works of Jingyue: Transmission of Loyalty” states: “Cold in the upper body leads to sour regurgitation, obstruction of the throat, indigestion, and bloating.” “Heat in the lower body leads to swelling and pain in the waist and feet, constipation, or heat pain with seminal emission, or turbid urine and red stools.”
Upper heat and lower cold, upper cold and lower heat are often caused by mixed cold and heat, with the pathology resulting from the imbalance of Yin and Yang Qi, or excess Yin in the upper body and excess Yang in the lower body; or excess Yang in the upper body and excess Yin in the lower body.
(3) Exterior Cold and Interior Heat: Cold is on the exterior, heat is on the interior, which is a manifestation of mixed exterior and interior cold and heat. This is commonly seen in cases where there is pre-existing internal heat, and an external invasion of wind-cold occurs; or when an external pathogen transforms into heat internally while the exterior cold has not resolved. Symptoms may include aversion to cold with fever, no sweating, headache, body aches, restlessness, thirst, and a floating tight pulse, indicating cold on the exterior and heat on the interior.
(4) Exterior Heat and Interior Cold: This is also a manifestation of mixed exterior and interior cold and heat. It is often seen in cases where there is pre-existing interior cold and then an invasion of wind-heat occurs; or when an exterior heat syndrome has not resolved, leading to damage of the spleen and stomach Yang Qi. Clinically, one may observe symptoms of fever, headache, cough, and sore throat indicating exterior heat syndrome, along with loose stools, clear urine, and cold extremities indicating interior cold syndrome.
When cold and heat appear simultaneously, it is essential to distinguish between exterior and interior, upper and lower, meridians and organs, and also to clarify the relative severity of cold and heat, as well as the primary and secondary aspects of the condition. These distinctions are crucial and serve as guidelines for treatment.
4.2 Transformation of Cold and Heat
（1）Cold Syndromes Transforming into Heat Symptoms: The primary cold syndrome later presents with heat symptoms, with the heat symptoms appearing and the cold symptoms disappearing. This often results from improper treatment, excessive use of warming and drying herbs; or failure to treat, where the cold pathogen has not been dispelled in time, leading to an excess of Yang Qi, and the cold pathogen transforms into heat. For example, a patient initially presents with severe aversion to cold, mild fever, a thin white and moist tongue coating, and a floating tight pulse indicating exterior cold syndrome. Due to mismanagement or failure to treat, the patient later develops high fever, no aversion to cold, but rather aversion to heat, restlessness, thirst, a red tongue with a yellow coating, and a rapid pulse indicating interior heat syndrome. This is a case of cold syndrome transforming into heat syndrome.
(2) Heat Syndromes Transforming into Cold Syndromes: The primary heat syndrome later presents with cold symptoms, with the cold symptoms appearing and the heat symptoms disappearing. This is also due to mismanagement or failure to treat, damaging Yang Qi; or due to excessive pathogenic Qi, depleting Zheng Qi, leading to an inability of Zheng Qi to overcome the pathogenic Qi, resulting in functional decline or failure. This transformation can be abrupt, such as in high fever patients, where excessive sweating leads to loss of Yang Qi, or excessive vomiting and diarrhea lead to loss of Yang Qi, resulting in a sudden drop in body temperature, cold extremities, pale complexion, and a weak pulse indicating deficiency cold (loss of Yang). It can also be gradual, such as in cases of prolonged heat dysentery that does not resolve, transforming into deficiency cold dysentery, which is a case of heat syndrome transforming into cold syndrome.
The mutual transformation of cold and heat syndromes reflects the dynamics of pathogenic and Zheng Qi. The transformation from cold syndrome to heat syndrome indicates that the body’s Zheng Qi is still strong, and the cold pathogen is stagnant and transforms into heat; the transformation from heat syndrome to cold syndrome often indicates that the pathogenic Qi is strong and Zheng Qi is weak, unable to overcome the pathogenic Qi.
4.3 True and False Cold and Heat
When a disease progresses to extreme cold or extreme heat, there may sometimes be false appearances that are contrary to the essence of the disease, such as “extreme cold appearing as heat” or “extreme heat appearing as cold,” known as true cold and false heat, true heat and false cold. These false appearances are often seen in critical situations of life and death, and if not carefully examined, can easily lead to misdiagnosis.
(1) True Cold and False Heat: This is a condition where true cold exists internally while false heat is observed externally. The mechanism of this condition arises from internal excess of Yin cold, which obstructs Yang externally, leading to a rejection of Yin and Yang cold and heat, also known as “Yin excess obstructing Yang.” Clinical manifestations include fever, red face, thirst, a large pulse, resembling heat syndrome, but the patient desires to cover themselves with blankets, has a preference for warm drinks, drinks little, has a large but weak pulse, and may also present with cold extremities, clear diarrhea, and long clear urination, along with a pale tongue with a white coating.
(2) True Heat and False Cold: This is a condition where true heat exists internally while false cold is observed externally. The mechanism arises from internal excess of Yang heat, which obstructs Yin externally, also known as “Yang excess obstructing Yin.” The more severe the internal heat, the more severe the cold extremities, hence the saying “deep heat leads to deep cold.” Clinical manifestations include cold hands and feet, a deep pulse, resembling cold syndrome, but the extremities are cold while the body is hot, with no aversion to heat, rather a preference for heat, a deep and rapid pulse, along with thirst for cold drinks, dry throat, foul breath, delirium, short and red urination, dry and hard stools, or severe heat dysentery, a red tongue, and a yellow and dry coating. The cold extremities and deep pulse are false cold phenomena, while the internal heat is the essence of the disease.
To differentiate between true and false cold and heat, one must understand the entire course of the disease and also pay attention to the following two aspects:
① The appearance of false phenomena is often in the extremities, skin, and complexion, while the internal manifestations of organs, Qi, blood, and fluids accurately reflect the essence of the disease. Therefore, when diagnosing, one should rely on internal signs, tongue appearance, and pulse condition as the basis for diagnosis.
② False phenomena are ultimately different from true phenomena. For example, false heat may present as a pale complexion with only a slight red flush on the cheeks, while true heat presents as a fully flushed face; false cold often presents as cold extremities while the chest and abdomen are hot to the touch, or the whole body is cold but the patient does not want to be covered; true cold is when the patient desires to be covered.
Regarding the differentiation of true and false cold and heat, ancient texts provide rich experiences, such as the “Complete Works of Jingyue: Transmission of Loyalty” which proposes the method of testing cold and heat: “False cold treated with warming herbs, false heat treated with cooling herbs, etc. Just test with a little cold water. False heat will not like water; if they do, or if they vomit after taking it, then warming herbs should be used to resolve it; false cold will prefer water, or if they feel better after taking it and have no adverse reactions, then cooling herbs should be used to resolve it.” This method can also assist in diagnosis.
5. Cold and Heat and Their Relationship with Exterior and Interior
Cold syndromes and heat syndromes are interrelated with exterior and interior, forming various syndromes. In addition to the aforementioned exterior cold and interior heat, exterior heat and interior cold, there are also exterior cold, exterior heat, interior cold, and interior heat syndromes.
5.1 Exterior Cold Syndromes
Exterior cold syndromes are symptoms resulting from the invasion of cold pathogens into the muscle surface.
Clinical manifestations: Severe aversion to cold, mild fever, headache and body aches, no sweating, a pale tongue with a thin white and moist coating, and a floating tight pulse.
Syndrome analysis: Cold pathogens invade the exterior, damaging the Wei Yang, which fails to warm the muscle surface, leading to severe aversion to cold; the righteous Qi contends with the evil, and Yang Qi is obstructed, resulting in mild fever and cold being a manifestation of Yin evil, hence severe aversion to cold with mild fever. Cold pathogens stagnate the meridians, leading to headache and body aches. Cold pathogens constrict, closing the pores, hence no sweating, and a floating tight pulse is also a sign of cold pathogens constraining the exterior.
5.2 Exterior Heat Syndromes
Exterior heat syndromes are symptoms resulting from warm heat pathogens invading the muscle surface.
Clinical manifestations: Fever, mild aversion to wind and cold, headache, slight thirst, or sweating, a red tongue with a thin yellow coating, and a floating rapid pulse.
Syndrome analysis: Heat pathogens invade the exterior, obstructing the Wei Qi, hence fever and aversion to cold; heat is a Yang pathogen, hence severe fever and mild aversion to cold, accompanied by slight thirst. Heat rises and disperses, leading to sweating. Heat pathogens disturb the mind, hence headache. A red tongue with a yellow coating and a floating rapid pulse are signs of warmth and heat in the exterior.
5.3 Interior Cold Syndromes
Interior cold syndromes are symptoms resulting from cold pathogens penetrating the internal organs or deficiency of Yang Qi.
Clinical manifestations: Cold body and limbs, pale complexion, lack of thirst or preference for warm drinks, quiet and reserved, clear and long urination, loose stools, a pale tongue, a white and moist coating, and a slow and deep pulse.
Syndrome analysis:Cold pathogens penetrate the internal organs or Yang Qi is deficient, failing to warm the body, hence cold body and limbs, pale complexion. Internal excess of Yin cold does not harm fluids, hence lack of thirst or preference for warm drinks. Cold belongs to Yin, which is quiet, and when functions decline, the patient becomes quiet and reserved. Clear urine and loose stools, a pale tongue with a white and moist coating, and a slow and deep pulse are all signs of interior cold.
5.4 Interior Heat Syndromes
Interior heat syndromes are symptoms resulting from external pathogens transforming into heat internally, or heat pathogens penetrating the internal organs, leading to excessive internal heat.
Clinical manifestations: Red face and body heat, thirst, preference for cold drinks, restlessness, talking excessively, yellow and red urine, dry and hard stools, a red tongue, a yellow coating, and a rapid pulse.
Syndrome analysis:Excessive internal heat rises to the exterior, hence red face and body heat; heat injures fluids, leading to thirst for cold drinks. Heat belongs to Yang, which is active, leading to restlessness and excessive talking. Heat damages fluids, hence yellow and red urine, and intestinal heat and fluid depletion lead to constipation. A red tongue, yellow coating, and rapid pulse are all signs of interior heat.
Editor: Yang Wenjie, Physician Email: [email protected]