(1) Characteristics of Floating Pulse
“Excessive when lifted, insufficient when pressed.”
The floating pulse is one of the so-called primary pulses, which has been emphasized by physicians throughout history. Just look at the “Cui’s Pulse Classic” to understand this. The characteristic of the floating pulse is “excessive when lifted, insufficient when pressed,” meaning it is very obvious when lightly taken, slightly less so when moderately taken, and even less so when deeply taken. The sensation under the fingers, including the strength of the pulse, is not obvious during moderate and deep palpation, which is the standard floating pulse. Some floating pulses may be high in position but have strength during moderate palpation; I generally classify these as floating vigorous pulses, which are not standard floating pulses. The standard floating pulse is “excessive when lifted, insufficient when pressed,” and it gradually becomes insufficient. The so-called “excessive” refers to the best pulsation being at a shallow position, with most of the strength being stronger than that of a normal person.
In clinical practice, non-standard floating pulses are more common. Therefore, when taking the pulse, it is essential to strictly follow the pulse diagnosis operational norms. The key to feeling the floating pulse is that the three fingers must be lightly placed, that is, naturally resting. Otherwise, if the finger strength is too great, floating weak pulses or even empty floating pulses may be missed. The transition from “excessive when lifted” to “insufficient when pressed” is a gradual process. I roughly classify floating pulses into four categories:
1. Floating: Obvious when lightly taken, insufficient when moderately taken, and even more insufficient when deeply taken, which is the typical floating pulse mentioned above.
2. Slightly Floating: Close to the standard floating pulse, but slightly less obvious. It should be quite obvious when lightly taken, moderately taken should also be relatively obvious, and lightly taken and moderately taken should be similar, but deeply taken is insufficient, unlike the standard floating pulse where lightly taken is very obvious, moderately taken is less so, and deeply taken is even more insufficient.
3. Slightly Floating: Requires a bit more strength to feel it clearly when lightly taken. If it is not very obvious when lightly taken but can still be felt, and moderately taken is also felt but insufficient when deeply taken, it is called slightly floating. This is also referred to as slightly floating, and its position is not very superficial.
4. Weakly Floating: If the lightly taken pulse is quite weak, with little strength when lightly taken, moderate strength also weak, and not obvious when deeply taken, it should be described as weakly floating or slightly weak. As stated in the “Jin Gui Yao Lue” regarding wind and seasonal diseases, “the Shaoyin pulse is floating and weak; weak indicates insufficient blood, floating indicates wind, and wind and blood clash, causing pain like a pulling sensation.” The floating pulse here should be described as weakly floating, indicating that the prominence of the pulse at the lightly taken position gradually decreases, but it can still be felt, and the deeply taken pulse does not exceed this pulse, which can be described as floating, but based on its decreasing prominence, the best description is weakly floating or slightly weak. Additionally, we need to discuss the characteristics of vigorous pulses, floating solid pulses, and floating weak pulses:
Vigorous Pulse: Obvious when lightly taken, with relatively good strength, stronger than that of a normal person, but when moderately taken, the strength is even greater than when lightly taken, resembling a bouncing pulse. Many floating pulses described in historical texts are actually vigorous pulses, which do not necessarily indicate exterior syndrome, while most floating pulses indicate exterior syndrome.
Floating Solid Pulse: The strength when lightly taken is mostly greater than that of a normal person, and the strength when moderately taken is even greater, and sometimes even greater when deeply taken.
Floating Weak Pulse: The strength when lightly taken is not great and soft, but should be obvious, not exceeding that of a normal person, with even poorer strength when moderately taken; the floating weak pulse is soft when lightly taken, and even softer when moderately and deeply taken, only that its strength when lightly taken is greater than that when moderately and deeply taken.
In summary, the key to determining whether it is a floating pulse in clinical practice is that the lightly taken pulse is very obvious.
(2) Mechanism of Formation and Diagnostic Significance of Floating Pulse
1. Evil Qi invading the exterior, with righteous Qi contending with evil Qi at the surface
External evil invading the muscle surface, the body resists the external evil, and Qi and blood move towards the surface to contend with the invading external evil. The righteous and evil Qi contend at the surface, and the Qi and blood of the body contend with the evil at the surface. The Taiyang exterior syndrome has righteous and evil contending at the skin, and the pulse is often a floating pulse; the Taiyin wind-damp exterior syndrome has righteous and evil contending at the four extremities, with the spleen’s exterior showing a floating weak pulse; the Yangming also has righteous and evil contending in the muscles, and floating pulses can also be seen. When Qi and blood of Yin and Yang move towards the exterior, the pulse will manifest at a shallow position. Physicians throughout history have said, “Floating pulse indicates exterior syndrome,” but clinical experience and literature suggest that the appearance of floating pulse symptoms is not always exterior syndrome, and exterior syndrome does not necessarily present with floating pulse.
2. Wind evil stirring, causing Qi and blood to flow to the surface
The wind evil here mainly refers to internal wind, or the wind of the meridians, that is, wind invading the channels. Internal wind is produced by the chaotic and erratic movement of Qi and blood within the body, especially when Yang Qi is excessively rebellious and moves chaotically, resembling the rapid, erratic, and variable nature of external wind evils among the six excesses, hence the name. Due to the stirring of internal wind, Qi and blood become excessively rebellious, leading to the nourishing blood rising and moving towards the exterior, flowing to the surface, and the pulse being filled with Qi and blood. In traditional Chinese medicine, herbs like Quanxie (Scorpion) and Wugong (Centipede) are used to dispel wind and open the channels, targeting the deeper wind in the meridians and muscles compared to the superficial skin. Therefore, the pulse can also be deep, but the strong disturbance of wind can also lead to a floating pulse, and even liver wind disturbance can present as a floating pulse. This type of exterior wind is deeper than the exterior wind treated by Guizhi Decoction. The floating pulse of internal wind often presents as vigorous or floating solid, with a small portion showing as standard floating pulse.
3. Yang Qi floating at the surface
The term “floating” is conventionally used to denote a vacuous mechanism, such as Yang deficiency or severe deficiency of Qi and blood. However, the Yang Qi of some overly ambitious individuals can also float outward. Yang Qi is meant to be stored; when Yang Qi loses its concealment, it will float out. Similarly, Qi can also lose its inward retention. Under the bubble economy, with a large investment in material wealth and healthcare, one would expect human lifespan to increase. Theoretically, people in Northern Europe, who live more leisurely than Americans, should live longer, but current statistics do not seem to show this. Of course, there are many other factors such as common and frequently occurring diseases that influence this. Yang Qi should be stored, and Qi should be retained; this is the normal state of the body. When Yang Qi is to be mobilized, it can be released at about 1/4 or 1/3, with most remaining stored internally, which is the normal ecology. For example, we often say, “Huangqi (Astragalus) moves but does not retain” and “Dangshen (Codonopsis) retains but does not move.” Huangqi can promote the upward movement and outward flow of the spleen and lung Qi; Dangshen promotes some movement of Qi while most remains stored, hence the saying “Huangqi moves but does not retain, Dangshen retains but does not move.” If the righteous Qi does not retain at all and is all externalized, it indicates a vacuous floating phenomenon. The body has no reserves left, and the investment has reached a point of bankruptcy, which may lead to a rupture of the financial chain; this is what is meant by vacuity!
(3) Differentiation of the Diagnostic Significance of Floating Pulse
1. Floating pulse caused by evil Qi invading the exterior can have different pulse patterns depending on the type of evil Qi
If it is caused by exterior evil, the pulse can be floating, and it can also be floating and wiry. It is not the case that a person with spleen deficiency in Zhang Zhongjing’s time would have a floating weak pulse due to wind; in today’s society, the result of restlessness and impatience often leads to adults having a floating wiry pulse when they catch a cold, except for children. In the case of cold damage, especially in male patients, even if it is exterior wind, the pulse is mostly wiry. If there is a combination of cold, the pulse can be floating and tight; if there is dampness, the pulse can be floating and weak, and the pulse may not flow smoothly, or may be weakly floating, indicating that the body’s dampness is quite severe, with both exterior and interior dampness; if there is exterior dampness, the pulse can also be floating and moist. If there is both exterior and interior dampness, pure floating and moist is rare; if there is a combination of wind-heat, then the pulse is floating and rapid. If it is evil Qi invading the exterior, the pulse is generally a standard floating pulse, but such cases are relatively rare. We cannot say that evil Qi invades the exterior and the patient has no internal illness; the exterior can affect the interior, and new illnesses can also affect chronic diseases. Therefore, standard floating pulses are relatively rare in clinical practice.
2. Floating pulse caused by wind evil stirring is often floating and wiry, with greater strength when moderately taken
If the wind here is limited to internal wind, then the floating pulse caused by wind evil stirring is often stronger when moderately taken. However, it should be noted that most of the wiry pulse when moderately taken is even more wiry than when lightly taken; the obvious wiry pulse is more pronounced when moderately taken, although the pulse may also be wiry when lightly taken.
3. Floating pulse caused by severe deficiency of Qi and blood or Yang Qi is often weakly floating, large floating, or large floating with a hollow center
If it is due to severe deficiency of righteous Qi, Qi may escape; if Yang Qi is floating, Yang may escape, leading to a loss of Yang. Often, strong individuals can endure for a while longer; this type of floating pulse can be weakly floating, or it can present as large floating or large floating with a hollow center. The large floating and large floating with a hollow center can present in two situations: one is large floating without a hollow center but with a strong rebound, such as a bouncing pulse or leather pulse, and the second is a general large floating with a hollow center pulse.
Through the differentiation of the mechanism of floating pulse formation, we can have targeted treatment in clinical practice. Exterior evil should be released from the surface, wind evil should be calmed, and Yang Qi that is floating should be supplemented and drawn inward, supplemented and retained.