How the human body reacts to shock waves
What is shock wave therapy?
Shock Waves are movements of extremely high pressure caused by, for example, an explosion, an earthquake or a plane breaking the sound barrier. Extracorporeal Shock Wave Therapy (ESWT) is the application of Shock Waves in medicine.
It is clinically proven that pressure waves, when applied to injured tissues, stimulate metabolic reactions:
- Reduction of pain felt by nerve fibers
- Increase of blood circulation in surrounding soft tissues
- Beginning of healing process triggered by stem cells activation
Shock Wave therapy and red hot chili peppers
Red chili peppers contain capsaicin. At first this substance overwhelms the so-called C nerve fibers responsible for transmitting pain but then disables them for an extended period of time. Everybody knows the feeling – first, the mouth is on fire, then it feels completely numb.
Research has indicated that shock wave therapy works the same way1. When activated, the C nerve fibers release a specific substance (substance P) in the tissue as well as in the spinal cord. This substance is responsible for causing slight discomfort during and after shock wave treatment. However, with prolonged activation, C nerve fibers become incapable for some time of releasing substance P and causing pain2.
Less substance P in the tissue leads to reduced pain, but there is more: less substance P also causes so-called neurogenic inflammation to decline3.
A decline in neurogenic inflammation may in turn foster healing – together with the release of growth factors and the activation of stem cells in the treated tissue4.
For more information on how shock wave therapy can help in a specific disease, please see the full list of indications.
1Maier et al., Clin Orthop Relat Res 2003; (406):237–245.
2In addition, shock waves activate the so-called Aδ nerve fibers (sensory afferent nerve fibers from the periphery) via receptors in the tissue.
According to Melzack and Wall’s gate control theory (Science 1965; 150:971–979) these activated Aδ fibers then suppress the conduction of pain in the second-order neuron of the sensory pathway in the dorsal horn of the spinal cord.
3The release of substance P, CGRP (calcitonin gene-related peptide) and other inflammation mediators from afferent nerve fibers is generally referred to as “neurogenic inflammation” (Richardson and Vasko, J Pharmacol Exp Ther 2002; 302:839–845). It is also linked to the pathogenesis of tendinopathies such as tennis elbow and plantar fasciitis (Roetert et al., Clin Sports Med 1995; 14:47–57; LeMelle et al., Clin Podiatr Med Surg 1990; 7:385–389).Shock wave treatment causes a drop in substance P and CGRP in the tissue (Maier et al., 2003; Takahashi et al., Auton Neurosci 2003; 107:81–84).
4Shock waves in the treated tissue lead to a stronger expression of growth factors such as BMP (bone morphogenetic protein), eNOS (endothelial nitric oxide synthase), VEGF (vascular endothelial growth factor) and PCNA (proliferating cell nuclear antigen) as well as to an activation of stem cells
(Wang CJ, ISMST Newsletter 2006, Vol. 1, Issue 1; Hofmann et al., J Trauma 2008; 65:1402–1410).