What is Microcurrent or Microcurrent Therapy?
Microcurrent is current in millionths of an ampere (micro ampere range). Bioelectric currents in the body are generally found to be in the micro ampere range.
Microcurrent therapy is based on the evidence that micro amperage currents closely approximate the naturally occurring bioelectric currents in the body and therefore effectively augment the body’s tissue healing and repair. It works because of it’s ability to stimulate cellular physiology and growth. One classic study showed that microamperage stimulation could increase ATP generation by almost 500%. Increasing the current actually decreased the results. The same study also demonstrated the ability of microcurrent to enhance amino acid transport and protein synthesis.
Background and Rationale
Contemporary accounts of tissue healing are typically expressed in terms of biochemistry. The actions and effects of substances such as cytokines and growth factor are said to initiate and mediate the various stages of inflammation and repair that normally follow tissue damage. Yet, evidence which has accumulated over many decades suggests that a full description of the physiology of healing must also include the role of bioelectricity. The importance of bioelectricity in functions such as nervous system signalling and muscle contraction has long since been understood, but it is also involved in many other physiological processes. These include the development, adaptation, repair and regeneration of tissues throughout the body.
Recognition of bioelectricity’s role in tissue healing provides a rationale for the therapeutic application of electric stimulation, particularly in cases where natural repair processes have broken down. Microcurrent therapy is an example of this. Uniquely amongst the various electrotherapeautic modalities, microcurrent therapy (MCT) involves application of voltages and currents of similar magnitude and form to those generated endogenously during normal tissue healing. MCT has been shown to be of benefit in several types of tissue healing and it may be effective in many others. It appears to stimulate healing generally and not just a specific element of the process; it has very few side effects and may offer an effective treatment for musculoskeletal disorders such as chronic tendinopathies where normal healing has become dysfunctional.
Bioelectricity and Healing
The human body in common with other living organisms expends a significant proportion of its energy generating electricity. The magnitude of this generated electricity is of the order of millivolts and where there is a conducting pathway, they cause the movement of ions within tissue constituting a bioelectric current, typically in the microaml (MA) range.
At the cellular level, biochemistry is involved in the transport through the membrane of ions that can influence cell behaviour. At the tissue level, endogenous fields are intrinsic to a number of metabolic processes, including development, adaptation and repair. These fields can influence cell morphology and the growth of body parts during foetal development; they are generated when connective tissues such as bone and tendons are stressed, and can influence adaptive modification in the extracellular matrix and when tissue is damaged they set up currents that appear to drive elements of the healing response. The currents diminish as healing progresses with normal values being re-established once healing is complete.
It has been established by a wealth of experimental evidence that bioelectricity is INTRINSIC in the previously mentioned processes and not a mere by-product. Proof positive of this can be observed in the fact that setting up of a voltage in opposition to the endogenous current or blocking the passage of bioelectric currents can slow or abolish the healing response in a variety of tissue types.
Application of microcurrent to tissue has been found to boost many organelles including ones responsible for cellular activities, and to increase concentrations of ATP, the cellular currency of energy. These changes can facilitate cell proliferation and protein synthesis, which are found to increase when microcurrents are applied to the constituent cells of skin, tendons, cartilage and bone. Such effects are highly parameter dependent, however. Larger currents or alternating microcurrents at certain frequencies have been found to reduce cell proliferation or induce cell death in some cases.
Ion channels in cell membranes may migrate under the influence of an applied field, resulting in cytoskeletal modifications including creation of membrane projections that enable cell movement. Directed movement of cells within an electric field – known as galvanotaxis – has been observed with many cell types. These include leukocytes and macrophages, which are key mediators in different stages of healing, as well as a variety of cells responsible for tissue formation, such as keratinocytes, vascular endothelial cells, osteoblasts, osteoclasts, chondrocytes and fibroblasts.
At the tissue level, unidirectional fields and direct currents can promote vascular permeability, angiogenesis and neural sprouting as well as formation of new skin, bone, cartilage and soft tissue. Such findings are significant because they suggest that applying fields and currents with similar parameters to bioelectricity may be used to stimulate tissue healing. Cell migration, proliferation and synthesis of new tissue are all components of the healing process. If applied electricity can mimic endogenous electrical signals that guide cellular behaviour, then a therapeutic option may be available where natural healing has failed.
Recap on the Role of ATP
Central to any healing process is the requirement for ATP which is the ‘currency’ that facilitates all the processes needed to complete effective healing.
The total quantity of ATP in the body is approximately 0.1 moles. The energy required by human cells needs the hydrolysis of 200-300 moles of ATP everyday. Thus each ATP molecule is recycled 2000-3000 times in a single day. ATP cannot be stored so its consumption must closely follow its synthesis.
It is established that the local ATP requirement at the site of injury is greatly elevated and microcurrent application addresses this shortfall and thus improves healing rates.
Effect of Microcurrent
The work of Cheng has shown that under the influence of microcurrent electrical stimulation ATP concentrations increase when the applied electrical current is in the 25 to less than 1000 microamp range. What this means is that nerve cell membrane potentials, which are normally maintained at around -85 mV in healthy tissue, are re-established by microcurrent stimulation. Levels of intracellular metabolic waste (i.e., lactic acid) are reduced and fresh concentrations of useable cellulat metabolites are introduced into the exhausted cell. At this point the cell can enter its regenerative phase, pain levels are noticeably reduced and regenerative functions can be re-established.
Cheng showed that ATP concentrations were increased by up to 300-400% in cells stimulated with current in the 25-1000 microamp range.
While our bodies in theory can produce all the ATP we need, the fact is they don’t. microcurrent stimulation between 200-800 microamps is a way of supercharging the tissue with ATP which can be used and distributed as required. By this means, much of the research that shows a 200% increase in healing rate can be explained as it applies to hundreds of conditions. In a clinical sense, any healing process requires a great deal of ATP and may be accelerated through a means of increasing ATP in the tissue. Microcurrent accomplishes this in ATP production.
Electrical Activity around the Trauma Site
Becker (1985) showed that trauma will affect the electrical potential of cells in damaged tissue. The injured site has a much higher resistance than that of the surrounding tissue. Electrical resistance of tissue with chronic pathology is higher than the immediate surrounding healthy or less pathological tissue. Basic physics dictates that electricity tends towards the path of least resistance. Thus, endogenous bioelectric current avoids areas of high resistance and takes the easiest path generally circumventing the injury. The decreased electrical flow through the injured area decreases the cellular capacitance (Windsor, 1993). As a result, healing is actually impaired. This may be one of the reasons for inflammatory reactions; local vaso dilation may ultimately cause the release of histamines and prosta glandins due to irritation of mast cells. The resultant oedema is a function of the net movement of fluid into the interstitial paces. When this happens, homeostatic mechanisms including vaso constriction of arterials and formation of platelet plugs come into play immediately to retard fluid loss. Pain, heat, swelling and redness are the characteristics of inflamed tissues. This inflammatory process takes the bodies energy and transforms it into heat (like a toasters elements when electricity is applied). The heating process is like a constant energy leak and can easily drain the body of critically needed energy.
Microcurrent Treatment Protocol
The first phase of a normal microcurrent is typically designed to stimulate the tissue and affect the electrical resistance of the skin/electrode interface with 4-6 mAmps of current. The second phase is an introduction of a current between 25-900 mAmps. This drives the increase in production of ATP which in turn fuels the transmigration of metabolite and metabolic waste across the cell membranes as well as the re-establishment of cellular capacitance.
Frequency Specific Microcurrent
The range of stimulation that falls within the biological wave band of the body’s electromagnetic energies appears to be quite narrow. Stimulation within this ideal range has been observed to illicit dramatically positive biological and clinical effects. Previous forms of electrotherapy which simply bombard the tissues with high intensity stimulation only serves to produce hyperstimulatory analgesia, temporarily muting the pain, but were to supercharge the cellular ATP levels as the electrical current was far outside the body’s natural biological waveband.
Much of the work establishing the frequencies that effectively stimulate the body was carried out in France by Paul Nogier MD. The most common frequencies used in Europe are multiples of 73 Hz, which they claim to be a primary resonant frequency of the body.
Each tissue in the body has individualised frequencies. The mechanics of how these frequencies are establishes and altered due to trauma, injury or environmental factors are complex and are not within the scope of this document.
The purpose or aim of microcurrent therapy is to neutralise those frequencies that are ‘incorrect’ as a result of trauma etc.; as the frequencies are normalised the physiological conditions of the tissues will begin to normalise. The rate at which these changes occur varies with each individual. Some patients may experience a notable change immediately after treatment – others may take up to 24 hours. On average, taking into consideration the resistance to change back to normalcy, it usually takes six treatments for the notable changes to become long lasting.
Microcurrent treatment should be repeated at appropriate intervals until the effects become permanent. The frequencies work on the principle of biological resonance. Microcurrent frequencies seem to be able to resonate with biologic tissue and change to structure of the tissue when the frequency is correct. Once the tissue is changes and stable it seems to be able to stay in the new configuration.
Overall Benefits of Microcurrent
Microcurrent electrical stimulation has been used and studied for many different applications. These include but are not limited to the following:
- Reduction in pain improvement scores with accompanying substantial reduction in serum levels of the inflammatory cytokines IL-1, IL-6 and TNF-X and neuropeptide substance P.Beta endorphin release and increase in serum cortisol
- Significant pain reduction and increased range of motion in chronic back pain, fibromyalgia, cervical pain, carpal tunnel syndrome and arthritis patients
- Reduction of pain in degenerative joint disease of the temporomandibular joint
- Lasting reduction in myofacial pain of the head, neck and face
- Reduction in post operative pain and oedema
- Increased rate of healing in injured athletes, pain control, increased rate of fracture repair
- Reduction in pain – superiority to conventional physical therapy in number of treatments required to relieve pain, severity of side effects, total cost of treatment and patient satisfaction
- Reduction in healing time of soft tissue injury
- Reduction in treatment and rehabilitation time and reduction in worker downtime
- Reduced severity in muscle damage signs and symptoms