Are Female and Male Meridians Different? Some Spontaneous Thoughts

It is a beautiful Sunday morning in Spring, 2012, in Austria and my wife and I are having breakfast, and drinking coffee. The sun is already shining early in the morning, and my wife says to me “Can you hear the birds? They are singing so lovely.” My answer is: “Yes, now I can hear it too.” She replies: “Women always hear everything a little bit faster and earlier”—and she is right. I remember very well some scientific investigations we performed when I was a young researcher. Already in the 1980s, we investigated auditory evoked potentials in humans, and we found that there were significant differences according to gender but not age within a group of 40 adults (mean age±standard deviation [SD]: 24.9±2.9 years, range 19–34 years).^1,2 Although these differences were very small (e.g., mean difference ∼0.000125 seconds), this result showed that the acoustic stimuli reached the centers in the brain in female volunteers earlier than in male volunteers. Our hypothesis concerning the main reason for these gender-specific differences in all latencies of the central components of the auditory evoked brainstem and middle latency auditory evoked potentials was based on the fact that women have smaller head circumferences, and therefore the acoustic pathway from the periphery (inner ear) to the specific brain areas is also shorter. That could be the reason why women can “statistically” hear everything faster and earlier than men.

Up to the Spring of 2012, associate professor Wei He, MD, PhD, from Beijing, in the People's Republic of China, had been working in my laboratory for several months. She is the head of the department of meridians at a very renowned acupuncture institute at the China Academy of Chinese Medical Sciences in Beijing. The previous week, we had discussed what meridians are and asked ourselves if there was anybody in the world who had actually seen meridians. We came to the conclusion that, at that moment in time—from the scientific point of view—nobody could reproduce, demonstrate, and visualize meridians. To my knowledge, this is still true as of this writing. This is supported by many review articles on this topic from all over the world, and also by some of our own investigations into thermography.^3–7 Seminal remarks by John Longhurst, MD, PhD (a professor at the Susan Samueli Center for Integrative Medicine, Department of Medicine, School of Medicine, University of California, Irvine CA) seem to be part of the ongoing discussion about thermography. In 2010, he wrote:

From my perspective, currently, there is nothing that needs to be added to this statement.

However, then, what are meridians if nobody can see them? The most common and simple explanation in the Western world is that meridians are so-called “energy pathways.” So, if a meridian is a pathway, then it has also a length as neural pathways or humoral pathways do. Because of the smaller average body height of women, this pathway is generally shorter and, therefore, energy transport can occur faster than it can occur in men. This is similar to the acoustic pathway within the brain. What else might be different in acupuncture between men and women?

In 2005, gender-related experiences were made in acupuncture in a study in Germany. ⁸ Patients received sham acupuncture in this study. “If the sham acupuncture needles were set by female therapists, patients were more frequently likely to believe that they received real acupuncture, than when male acupuncturists were at work,” said the first author in an interview. The study also showed that women responded to acupuncture and placebo more often than did men: Fifty percent of female patients treated with acupuncture, but only 25% percent of men improved. The major factors contributing to the response were the gender of the patient (females had better results) and the gender of the treating physician (the patients treated by females also had better results). Enck et al.'s ⁸ study was limited, however, and, this relationship of gender to results was not statistically secured; thus, these results must be confirmed by further studies.

If meridians in women tend to be shorter simply because women tend to be shorter, the possibility exists that the energy transport can be faster in women than in men. Are there consequences in basic research and clinical acupuncture studies? For some answers please read the articles of this special Women's Health issue of Medical Acupuncture.