Acupuncture and Pain: The Science Behind How Acupuncture Relieves Pain
Pain is a common reason for patients to seek acupuncture. In fact, chronic pain affects over 1.5 billion people globally,(1) with nearly one-third of American adults experiencing it(2). The most prevalent sources of chronic pain include low back pain (29%), neck pain (16%), and severe headache or migraine pain (15%)(3). Of these, back and neck pain are the most commonly pain-related issues seen at Jackupuncture. When helping these patients, I first identify neuromuscular dysfunction–which can be experienced as weakness, joint instability or shaking against resistance—and then restore it using electroacupuncture. This is what makes Jackupuncture so effective and innovative as an acupuncture clinic. However, this isn’t the approach most people are familiar with. What most people have experienced or heard about is the more traditional approach to acupuncture. So, in this article, we’ll be diving into some of the science behind how acupuncture in general helps people in pain.
The Neural Acupuncture Unit Concept
You’ve probably heard of Qi, Yin, Yang, and Meridians/Channels. While you may not be fluent in how these concepts guide clinicians in their work as acupuncturists, you probably know they have something to do with energy, balance, and flow. Traditionally, an acupuncturist focuses on strengthening/tonifying qi, balancing yin and yang, and helping qi and blood flow in the meridians/channels. As these goals are met, the body begins to achieve homeostasis, experience less pain, and heal. The Neural Acupuncture Unit (NAU) concept helps explain what’s happening during an acupuncture treatment from a western scientific perspective, giving more modern language to these traditional concepts and explaining how this effective modality achieves success for patients in pain.
The NAU concept is based on over 60 years of modern acupuncture studies in humans and animals. Drawing upon this research, the idea of acupuncture points as neural units explains how needling specific areas of the body achieves pain relief/analgesia, as well as many of the other health benefits of acupuncture treatment. Understanding acupuncture points as neural units makes it easier to understand acupuncture’s inner workings, which can actually get quite complicated. To keep things simple and clear, we’ll mostly be focusing on the big picture.
Acupuncture Points as Neural Units
First, let’s think about the body and where acupuncture points lie. Many commonly-used acupuncture points are in areas of the body where nerves and vessels are closer to the surface of the skin. This means acupuncture points are areas of more densely concentrated neural and neuroactive structures. Thus, “neural” units. As a consequence, insertion of a needle in these areas elicits a more efficient and therapeutic response from the brain and peripheral nervous system compared to non-acupuncture points. This is the basic foundation of acupuncture points as neural units.
At this point, patients usually ask one of 2 questions (sometimes, both): how does stabbing someone with a needle induce healing? Isn’t the response to the needle inflammatory, and isn’t that bad? Let’s start with the second question first: inflammation is part of the body’s natural healing response. Only if the inflammatory response becomes chronic and/or active at inappropriate times is it a problem. Secondly, we aren’t stabbing anyone. But that’s a good point. Let’s look at the needle and its insertion a bit more closely.
Acupuncture needles are the thickness of a single strand of hair, usually somewhere between .16-.30mm in diameter. This fine needle creates just enough damage in the region to activate a healing response without creating appreciable injury. This response is led by neuroactive and non-neuronal cells, which release neuropeptides like Substance P and histamine (“inflammation”), as well as other “various transmitters, modulators, inflammatory and immune factors, which directly or indirectly act at corresponding receptors on the surface of peripheral afferent [nerve] fibers”(4). This includes important chemicals you’ve probably heard of in relation to athletic and cognitive performance, as well as healing and mental health: ATP, serotonin, nitric oxide (NO), dopamine, noradrenaline (NA), γ-aminobutyric acid (GABA), and Acetylcholine.
Different Stimulus, Different Medicine
Depending on the specific stimulus applied to the needle, different responses can be elicited. For example, the common thrusting of manual acupuncture (MA)/dry needling activates a response from cutaneous receptors (Merkel, Meissner, Ruffini, and Pacinian corpuscles), sarcous sensory receptors (muscle spindles and tendon organs), and several different nerve fibers, while adding a twist activates an additional set of nerve fibers. This makes different types of needle stimulus more or less appropriate for different conditions and individuals (which is why it is important to receive any kind of needle therapy, including dry needling, from an experienced licensed acupuncturist). The different types of nerves in the area dictate what the sensation feels like to the patient. These sensations can range from heaviness, numbness, soreness, and achiness, all of which are transmitted by respective nerve fibers. The pain-relieving effects of acupuncture isn’t limited to these local responses, either.
Studies involving brain imaging show that electroacupuncture like that provided at Jackupuncture can excite a pain-relieving response in the brain. In these cases, a signal from the periphery of the body is activated by the needle at the acupuncture point/neural unit. This signal travels to the corresponding location of the spine, which reaches specific areas of the brain. The brain then releases endogenous opioids, its natural pain relievers. As with the body’s response to different kinds of manual stimulation (i.e., thrust vs twist), different electrical frequencies have been shown to release different kinds of pain relievers from the brain. Thus, depending on the location and type of stimulation applied to the needle, a vast array of pain-relieving and therapeutic responses can be activated locally and centrally (i.e., in the brain).
Wrapping It Up
In essence, acupuncture points are anatomical locations whose unique neurophysiological composition make them exceptionally effective sites for communicating with our peripheral (i.e., autonomic) and central (i.e., spine and brain) nervous systems. Depending on the location of the point, the depth of needling, and type of stimulus applied to the needle, specific signals can be communicated. The central and peripheral nervous systems’ chemical responses to these signals from neural units (acupuncture points) lead to pain relief and injury healing. These responses are what traditional acupuncturists identify as “tonifying Qi,” “nourishing Yin” or “moving Qi and blood.” Thanks to modern studies and the NAU concept, we have new language for understanding the body’s pain-relieving response to acupuncture.
References
1. National Center for Health Statistics (2006) Health, United States, 2006 Available from: https://www.cdc.gov/nchs/data/hus/hus06.pdf
2. Johannes, C. B., Le, T. K., Zhou, X., Johnston, J. A., & Dworkin, R. H. (2010). The prevalence of chronic pain in United States adults: results of an Internet-based survey. The Journal of Pain: Official Journal of the American Pain Society, 11(11), 1230–1239. https://doi.org/10.1016/j.jpain.2010.07.002
3. National Center for Health Statistics (US. “Health, United States, 2016: with chartbook on Long-term trends in health. Hyattsville, MD. 2017.”
4. Zhang ZJ, Wang XM, McAlonan GM. Neural acupuncture unit: a new concept for interpreting effects and mechanisms of acupuncture. Evid Based Complement Alternat Med. 2012;2012:429412. doi: 10.1155/2012/429412. Epub 2012 Mar 8. PMID: 22474503; PMCID: PMC3310280.
Russell, D. & Hopper Koppelman, M. (2017). Acupuncture For Pain. Evidence Based Acupuncture
All images: Zhang ZJ, Wang XM, McAlonan GM. Neural acupuncture unit: a new concept for interpreting effects and mechanisms of acupuncture. Evid Based Complement Alternat Med. 2012;2012:429412. doi: 10.1155/2012/429412. Epub 2012 Mar 8. PMID: 22474503; PMCID: PMC3310280.