Why 30 Minutes? The Ancient Logic Behind Acupuncture Needle Retention

Have you ever wondered why, in the majority of clinical settings, acupuncture needles are retained for exactly 30 minutes? Is this half-hour standard merely a matter of convention, or is there a deeper rationale behind it? The answer is far from arbitrary; it is, in fact, rooted in the precise rhythms of the body’s circulation.

In clinical acupuncture, the treatment does not conclude the moment the needle is inserted; the duration of needle retention is an integral part of the process. The length of retention is often dictated by the nature of the condition, the waxing and waning of pathogenic and upright Qi, and the rhythmic flow of channel Qi. Put simply, urgent cases demand swift action, whilst chronic conditions require nourishment. Acute conditions, wherein excess pathogens predominate, often call for brief retention or rapid insertion and withdrawal. Conversely, chronic conditions characterised by deficiency or obstruction due to stasis typically require a suitably longer retention time to support the Upright, move Qi, and harmonise Ying and Wei.

In Chinese medicine, there exists a technique known as "rapid needling," where the needle is inserted and withdrawn immediately without retention. This method is generally employed for repletion patterns involving accumulation and stagnation, where rapid manipulation suffices to unblock and vent Qi. Examples include treating paediatric food accumulation or a stye. In acute disorders—mostly repletion in nature—the pathogen tends to remain relatively superficial; thus, prolonged retention is unnecessary. Retention is usually brief, with approximately 15 minutes being commonly appropriate. For chronic disorders, which are often deficiency patterns or patterns of stasis, retention should be suitably extended to nourish Qi. Common recommendations include 30 minutes, 60 minutes, or longer.

Classical texts have long discussed the duration of needle retention. The Wushi Ying (Fifty Circulations) chapter of the Lingshu states:

《灵枢·五十营》原文： 黄帝曰：余愿闻五十营奈何？岐伯答曰：天周二十八宿，宿三十六分；人气行一周，千八分，日行二十八宿。人经脉上下、左右、前后二十八脉，周身十六丈二尺，以应二十八宿。漏水下百刻，以分昼夜。故人一呼脉再动，气行三寸；一吸脉亦再动，气行三寸。呼吸定息，气行六寸。十息，气行六尺，日行二分。二百七十息，气行十六丈二尺，气行交通于中，一周于身，下水二刻，日行二十五分。五百四十息，气行再周于身，下水四刻，日行四十分。二千七百息，气行十周于身，下水二十刻，日行五宿二十分。一万三千五百息，气行五十营于身，水下百刻，日行二十八宿，漏水皆尽，脉终矣。所谓交通者，并行一数也。故五十营备，得尽天地之寿矣，气凡行八百一十丈也。

"The Yellow Emperor asked: 'I wish to hear about the Fifty Circulations; what are they?'

Qi Bo replied: 'Heaven cycles through the twenty-eight lunar mansions; each mansion has thirty-six divisions. Human Qi completes one circuit in one thousand and eight divisions, and in one day it traverses the twenty-eight lunar mansions. The channel vessels of the human body—above and below, left and right, front and back—number twenty-eight in all. The body measures sixteen zhang and two chi in circumference, corresponding to the twenty-eight lunar mansions. The clepsydra drips one hundred ke to divide day and night. Therefore, with one exhalation, the pulse moves twice, and Qi advances three cun; with one inhalation, the pulse moves twic,e and Qi advances three cun. When breathing is even and settled, Qi advances six cun. In ten breaths, Qi advances six chi, which is two divisions in a day. In two hundred and seventy breaths, Qi advances sixteen zhang and two chi; Qi communicates and connects within the centre, making one circuit through the body while the water drops two ke, which is twenty-five divisions in a day. In five hundred and forty breaths, Qi makes a second circuit through the body while the water drops four ke, which is forty divisions in a day. In two thousand seven hundred breaths, Qi makes ten circuits through the body while the water drops twenty ke, which is five mansions and twenty divisions in a day. In thirteen thousand five hundred breaths, Qi makes fifty circulations through the body while the water drops one hundred ke, and in one day it traverses the twenty-eight lunar mansions; the clepsydra is exhausted, and the pulse comes to its end. What is meant by communicate and connect is that they proceed together as one count. Thus, when the fifty circulations are complete, one attains the full span of Heaven and Earth, and Qi travels a total of eight hundred and ten zhang.'"

Based on this passage, a simple explanation follows. Chinese medicine emphasises the unity of Heaven and humanity. As the Earth completes one rotation, the twenty-eight lunar mansions are observed in sequence. Since each mansion is subdivided into thirty-six parts, a full circuit of the twenty-eight mansions totals 1,008 parts. Over this full circuit, human Qi also completes one full revolution. This corresponds to one complete cycle of the waxing and waning of channel Qi across the twelve primary channels in the system of Ziwu Liuzhu (Midnight-Noon Ebb-Flow).

In antiquity, time was recorded using a clepsydra (water clock). In one day and night, the water drops one hundred ke. Therefore, within a 24-hour period, each ke equals 14.4 minutes—approximately 15 minutes. This is why a "quarter" (ke) is historically understood as roughly 15 minutes.

This 24-hour period also represents a Taiji cycle of Yin and Yang transformation. Within this daily Taiji cycle, there are one hundred ke. The passage states that Qi communicates and connects within the centre, making one circuit through the body while the water drops two ke. In other words, every two ke (approximately 28.8 minutes), the Ying and Wei Qi complete one circuit. Over 24 hours, fifty such circuits are completed.

This provides the theoretical basis for the common practice of retaining needles for 30 minutes per session. Through needling techniques, stimulation strengthens the movement and circulation of channel Qi. To enhance the therapeutic effect, the duration is often increased in multiples of 30 minutes; thus, the needle may be retained for 60 minutes or longer.

Needle retention is not a rigid rule, but a dynamic choice based on pattern differentiation and rhythmic movement. Acute repletion conditions often emphasise swift opening and venting, where brief retention produces results. Chronic deficiency or stasis conditions place greater emphasis on tonification and movement; here, channel Qi requires more time to circulate, gather, and adjust. When the classical rhythm of the Fifty Circulations is integrated with clinical pattern differentiation, it becomes clear why common durations such as 15, 30, and 60 minutes are not arbitrary, but are grounded in both empirical experience and theoretical reasoning. Ultimately, the key lies in adapting to the individual, the pattern, and the time.