Sweating is a natural and essential process that helps regulate body temperature and eliminate waste. It occurs when the body's internal and external temperatures rise, allowing the body to cool down through evaporative cooling. When temperatures decrease, sweating stops to prevent heat loss. The sweat glands are controlled by the autonomic nervous system, so increased sympathetic nervous system activity due to stress or arousal can also lead to increased sweating.
There are two types of glands that produce secretions on the skin: eccrine glands and apocrine glands. Eccrine glands are found all over the body and release a dilute solution of sodium chloride onto the skin to help regulate body temperature. Apocrine glands, on the other hand, release their secretions into hair follicles, and are concentrated in areas like the armpits, groin, and scalp. They produce a thicker, more viscous sweat that is thought to be associated with pheromones in mammals.
Excessive sweating is generally not considered a problem unless it interferes with daily life. Night sweats, for example, can be particularly uncomfortable and disruptive to sleep, and are a common concern in Chinese medicine clinics. People with excessively sweaty palms may also seek treatment, as clammy hands can be socially awkward. Spontaneous sweating, although relatively rare, is also an important factor in Chinese medicine diagnosis.
A night sweat is a type of sweating that occurs while the person is asleep and stops when they wake up. People who experience night sweats often wake up feeling hot and sweaty, dry off, and then fall back asleep, only to start sweating again.
Spontaneous sweating is a type of sweating that occurs without any physical exertion or exposure to hot water, overdressing, exercise, or diaphoretic foods or herbs. People who experience spontaneous sweating feel moist and clammy when touched, regardless of the season or their mental state. Spontaneous sweating can be generalized, affecting the entire body, or localized to specific areas such as the hands and feet, head, chest, armpits, or genitals.
Hemihydrosis, also known as sweating on one side of the body only, is a condition in which a person sweats on only one side of their body. The problem is usually on the side that doesn't sweat. Hemihydrosis is often related to neurological conditions such as stroke.
Yellow staining of clothing due to sweat is a condition in which the sweat produced by the body causes yellow stains on the clothing. This can be caused by a variety of factors, including the presence of certain chemicals or substances in the sweat, or the interaction of sweat with clothing fibers.
Physiology of Sweat
Sweating is a crucial mechanism for maintaining the balance of yin and yang in the body. Sweat is produced from body fluids, which are derived from the food and fluids that a person ingests. In Chinese medicine, sweating is closely associated with the function of the heart, lungs, and spleen, and is a function of the relationship between yin fluids and yang qi, specifically the yang qi that resides on the surface of the body, known as protective qi. Protective qi acts as a gatekeeper, allowing excess physiological heat to be released as sweat while preventing the entry of external pathogens. Similarly, when heat needs to be retained, the protective qi shuts down the exits to prevent excessive cooling.
Sweat is considered the fluid of the heart in Chinese medicine. The heart is responsible for governing blood, and both blood and sweat are derived from the essence of food and fluids. Excessive sweating can deplete the blood and harm the heart. This means that the heart is sensitive to excessive sweating, which can lead to cardiovascular collapse when severe. Heart yang deficiency can also cause profuse sweating. In less severe cases, sweating that occurs when a person is nervous or anxious has an emotional component related to deficiency of heart qi and disturbances of the spirit.
Protective qi, which is closely connected with lung qi, controls the opening and closing of the pores. Therefore, any factors that weaken the lungs will also weaken protective qi and its control over the surface of the body. In Chinese medicine, this can have significant consequences, as the protective qi plays a crucial role in protecting the body from external pathogens and maintaining the balance of yin and yang.
Spleen and Stomach
The spleen and stomach are considered the root of acquired qi and the qi of all other organ systems in Chinese medicine. Weakness of the spleen is a common cause of weakness of protective qi. The spleen also controls the limbs, so pathology of the spleen and stomach is often implicated in sweating of the hands and feet. In general, maintaining the health and function of the spleen and stomach is crucial for maintaining overall health and preventing a range of disorders, including those related to sweating.
In Chinese medicine, the liver plays a secondary role in sweating. Its main influence is through the generation of internal heat from constrained qi and the weakening of the spleen and depletion of qi that results from disruptions to the liver-spleen axis. Prolonged liver qi constraint generates heat, which can dry out and damage yin, eventually leading to ascendant yang. The expansive nature of heat and ascendant yang, combined with the body's attempts to shed excess heat, can lead to sweating.
The liver also indirectly influences the lungs and the lungs' control of protective qi and pores through the reverse controlling cycle. This can explain some types of excessive sweating seen in stressful situations. In general, maintaining the health and function of the liver is crucial for preventing a range of disorders related to sweating and other bodily functions.
Abnormal sweating can be divided into excess and deficiency types in Chinese medicine. Excess sweating is typically caused by the presence of heat or damp-heat in the body that the body is trying to eliminate. These pathogens may be the result of external invasion or may be created by internal imbalances. Deficiency sweating is associated with weakness of protective qi, yang qi deficiency, or yin and blood deficiency. Weakness of protective qi allows fluids to leak out, while yang qi deficiency results in excessive sweating during the day. Yin and blood deficiency sweating mostly occurs at night.
Sweating is often a feature of febrile disorders, but it is generally secondary to the main symptoms of fever, cough, diarrhea, and so on. Persistent sweating as a presenting symptom is more common after a febrile illness and may persist for some time after the initial illness has passed. This is because the pathogen responsible for the initial episode has not been completely cleared or because its presence has damaged qi and yin.
There are two main locations in which pathogens can linger and cause excessive sweating in Chinese medicine: the qi level and the nutritive level. The qi level incorporates the shao yang level, as they both exist between the surface and deepest layers of the body. The difference between the qi level and the shao yang level is that qi level pathology is more closely associated with the lungs, spleen, and stomach, while shao yang pathology involves the gallbladder. In terms of location, pathogens in the qi level lead to sweating on areas that are functionally associated with the lungs, spleen, and stomach: the whole body, or just the chest, head, and face, or hands and feet. Shao yang sweating can be systemic or just on areas that are functionally associated with the gallbladder and liver systems: the genitals and armpits. The sweating of shao yang syndrome is intermittent, appearing as the feverish phase of the cycle occurs.
In Chinese medicine, emotions that impact the lungs, spleen, or heart can lead to abnormal sweating. Persistent worry, brooding, sadness, and rumination can deplete the lungs and spleen, reducing the production of qi, including protective qi. Repeated invasion of the spleen by the liver in response to repressed emotion can also lead to depleted qi. Any situation that disperses heart qi, such as a sudden or severe shock or prolonged extreme stress, can increase sweating. Maintaining emotional balance and healthy functioning of these organ systems is crucial for preventing excessive sweating and other related disorders.
In Chinese medicine, constitutional or inherited weakness of the lungs and spleen is often associated with poor control of sweating. People with this condition may also experience general weakness and lack of vitality, respiratory problems such as asthma, and poor immunity. A constitutional weakness of heart qi can also contribute to excessive sweating. These individuals tend to be anxious and nervous from an early age, with sweating triggered by stress and anxiety. Strengthening the lungs, spleen, and heart through proper diet and lifestyle habits can help to prevent excessive sweating and improve overall health and well-being.
Excessive sweating can be a side effect of certain medications, including pseudoephedrine, antidepressants, aspirin, and nonsteroidal anti-inflammatory drugs (NSAIDs), hypoglycemic agents, caffeine, theophylline, and withdrawal from opiates. Excessive alcohol consumption can also contribute to chronic increased sweating. If you are experiencing excessive sweating and are taking any of these medications, it is important to talk to your doctor about possible alternatives or ways to manage the side effect.
In Chinese medicine, pathological sweating is caused by either an external pathogen or internal deficiency. Careful distinction must be made between these two causes in order to apply the appropriate treatment strategy. Eliminating external pathogens requires all pathways of elimination to remain open and clear so that the pathogen has an escape route. Deficiency patterns, on the other hand, require tonification and astringency to consolidate the leakage and prevent the escape of vital fluids. Improper treatment can cause a pathogen to become even more trapped or can worsen a deficiency. It is important to consult a qualified practitioner in order to receive a proper diagnosis and treatment plan.