Nick Grantham weighs up the evidence for magnetic therapy, the over the counter remedy with increasing pulling power.
The world of rehabilitation and performance enhancement is not an exact science. If it were, prescription and cure would be very straightforward and many of us therapists would be looking for alternative employment! But we all know that what works with one patient will have no impact on another, and sometimes an intervention will work that just doesn’t really make sense. And there are many apparently nonsensical treatments out there, which you may need to make judgements about from time to time.
So where do you stand on the matter of magnetic therapy? In the blue corner we have the scientific community, which has gathered observable, empirical and measurable evidence that largely dismisses magnetic therapy as mumbo jumbo. In the red corner we have a growing number of contenders from pseudo-science who believe magnets work and can play a part in the rehabilitation of injuries. Sitting out in the cheap seats are those of us (myself included) who until now have not paid much attention to this intervention and have no idea what to make of it.
I guarantee, however, that at some point soon one of your clients will ask you for your opinion on magnetic therapy. This treatment is already massively popular and is on the rise. Just on Google alone, the internet’s favourite search engine, you can find more than two million web references to magnetic therapy. To help you make up your mind, here is a summary of what the research evidence tells us.
What is magnetic therapy?
The origins of magnetic therapy date back to the 3rd century AD when Greek physicians were using rings of magnetised metal to treat arthritis and pills made of magnetised amber to stop bleeding(1, 2). The origins of modern treatments are often traced back to Paracelsus (1493-1541), a physician and alchemist who believed magnets could attract diseases and leach them from the body(3).
During the 18th century, Maximillian Hell claimed several cures using steel magnets, and Franz Anton Mesmer promoted his theories of ‘animal magnetism’. The existence of Mesmer’s theory was scientifically examined by a French Royal Commission set up by Louis XVI in 1784. The Commission included Benjamin Franklin and Antoine Lavoisier among its members and concluded that all the observable effects could be attributed to the power of suggestion(3).
Since those times, material scientists and engineers have developed stronger and stronger permanent magnets. In recent years there has been a growing interest in magnetic therapy, and research into this area continues in an attempt to establish the efficacy of the various potential applications.
The popularity of this alternative therapy is boosted by reports of its use by professional athletes, including former American football players, professional tennis players including Lindsay Davenport, footballers, cyclists, champion snowboarders, skiers and world champion kayakers. These sporting figures have deployed a variety of magnetic therapies to reduce pain and improve their performance. In a 1998 piece from The New York Times, the senior PGA golfer Jim Colbert described how he had ‘strapped magnets on to his back’ and put ‘magnetized insoles in his shoes’. He went on to explain how he came from eight shots off the lead to finish one off the winning score. Colbert has been wearing magnets ever since, has won well over $5m in 11 tournaments and was awarded Senior PGA Tour Player of the Year two years in a row. Is his success attributable to the use of magnets? Who knows, but you can see why people want to go out and buy these products.
Magnets produce a type of energy called a ‘magnetic field’. A magnet’s power of attraction is strongest at its opposite ends (north and south poles). The north and south poles attract each other, but north repels north and south repels south. All magnets attract iron. Magnets come in different strengths, usually measured in units called gauss (G). The Earth has a magnetic field of about 0.5G; fridge magnets range from 35 to 200G; magnets marketed for the treatment of pain are typically 300 to 5,000G; and MRI machines can kick out up to 200,000G(2).
Most of the products on the therapeutic market are static (or permanent) magnets: they have magnetic fields that do not change. Products using static magnets include:
* shoe insoles
* heel inserts
* mattress pads
* bandages and plasters
* pillows and cushions
* bracelets and other jewellery
A variety of theories exist relating to the application of static magnets in the treatment of pain, from those proposed by scientific research to claims made by product manufacturers. These theories include: changes in cell function, restoration of balance between cell death and growth, and increased blood flow resulting in improved oxygen and nutrient delivery.
An electromagnet generates a magnetic field when an electrical current is passed through a wire coil wrapped around a magnetic core. Electromagnets can be pulsed, by having the magnetic field turned on and off rapidly. Products using electromagnets deliver treatments through a variety of methods including:
* pads, cushions and mats that a patient lies on whilst pulsed electromagnetic fields are passed through them
* cylindrical treatment heads mounted on adjustable brackets that direct a pulsed electromagnetic field to the area of injury
* small portable units for use in a variety of settings to provide local application of pulsed electromagnetic fields.
Some of the concepts supporting the use of electromagnets include the alteration of how nerve cells respond to pain and the brain’s perception of pain, and alterations of white blood cells to reduce inflammation and improve the body’s ability to combat infection. Supporters of the use of pulsed electromagnets claim they can help in the treatment of wounds, soft tissue injuries, mechanical neck disorders, osteoarthritis, acute postoperative pain and the treatment of bone fractures(3).
Claims have been made that static magnets can increase the flow of blood and therefore the delivery of oxygen and nutrients to tissues(5). This could potentially aid recovery from exercise and improve subsequent athletic performance. One theory is that magnets cause water molecules in the blood to line up, leading to improved circulation. This view is not supported by John Schenck, who worked in the research and design laboratory of General Electric. Schenk explains that, to be able to align water molecules in the blood, you would need a magnet thousands of times stronger than any that have ever been created on Earth(4).
Another theory is that static magnets attract iron-rich blood to the area being treated. Yet the iron in our blood is very different from metallic iron. The latter is strongly magnetic because the individual atomic magnets are strongly coupled together. The iron atoms in our blood are magnetic, but they are so far away from other iron atoms that they remain magnetically independent(3). The US physics professor Robert Park dismisses this theory, stating that no magnet can attract blood, and offers a simple test to confirm his viewpoint. Increased blood flow to an area being treated with a static magnet would show up as a flushing or reddening of the skin. Place a magnet against your skin and see what happens(4). Recent research supports Park’s comments. A study conducted in Maryland found that blood flow was not significantly different when comparing the results of the use of magnets with a placebo (wearing of commercially available static magnets and placebos for 30 minutes on two separate occasions)(5).
Pulsed electromagnetic field therapy is used in the rehabilitation of soft tissue injuries(6), fractures(7, 3), the control of infection and inflammation(6) and the treatment of osteoarthritis(8). In an attempt to establish its efficacy as a treatment option for osteoarthritis, several studies have reviewed the literature. Initial reviews by Hulme et al(9) concluded that the limited evidence did not show a clinically significant benefit. These findings have recently been supported by a review of literature 1996 to 2005, completed by a team based at the Warwick Medical School and the Centre for Rehabilitation Science in Manchester, England. Their systematic review concluded that pulsed electromagnetic field therapy has little value in the management of knee osteoarthritis(8).
However, it has recently been highlighted that the exclusion of several key studies from that review may have produced a bias in its conclusions(10). Studies conducted in 1993 and 1994 examining the use of electromagnetic fields in the treatment of knee and spinal osteoarthritis show that this form of therapy can be highly effective(11, 12).
There are more than 15 published research papers looking at the various applications of magnetic therapy, of which perhaps the most commonly stated benefit is pain relief. Many manufacturers produce thin magnets mounted in a variety of products that can be applied to the body with the magnetic field emanating from the surface(3). If you suffer from migraines and headaches you can wear magnetic headbands, earrings or necklaces. You may, however, want to save your money. If the static magnets do have any effect on the body, the depth of penetration of the magnetic field is likely to be limited to a few millimetres. Professor Robert Park reports that the therapy magnets he has examined appear to be basically the same as the flat, flexible magnets that adorn most people’s domestic fridge doors. Park tested a pair of magnets from a magnet therapy kit. Although they were a little stronger and thicker than the typical refrigerator magnet, he reported that they still failed to hold even 10 sheets of paper on a file cabinet. Ten sheets is about one millimetre thick, which means, according to Park, that the magnetic fields would barely penetrate the skin. It would appear that not only do these magnets have no power to heal, they don’t even reach the site of pain or injury(4).
It may be a different story with weak pulsed electromagnets. Research with rats has shown that long-term use (four hours a day for 28 days) of a weak pulsed electromagnet(13) is linked to changes in the number of receptors of the brain chemical serotonin, which influences stress and pain. Another study using rats has shown that 30 minutes’ exposure to weak pulsed electro- magnetic fields has an analgesic effect lasting up to 30 minutes(14). What works in rats may not apply directly to humans, of course, so more research into this area is clearly needed.
Much of magnetic therapy falls into the realm of pseudo-science, or alternative therapies, but this does not mean it should be brushed aside. Research must continue in this area if we are to ensure that the clinical advice we are providing is appropriate and effective. The mechanisms by which static magnets might be used in rehabilitation and performance enhancement have not been conclusively identified or proven(1). Improvements and treatment effects are difficult to establish and may be a result of factors other than the targeted intervention strategy. In many cases it is hard to rule out the placebo effect.
Should we wait for an evidence base before we use electromagnetic therapies or can we rely on limited evidence and the growing body of anecdotal support for this alternative treatment? While more research is needed, it would seem that electromagnetic field therapy might have a use in the treatment of pain and injury.
1. Basford, JR ‘A historical perspective of the popular use of electric and magnetic therapy’. Archives of Physical Medicine and Rehabilitation. 2001: 82, 1261-1269.
2.Research Report: Questions and Answers About Using Magnets to Treat Pain.National Center for Complimentary and Alternative Medicine.
3. Livingston, JDMagnetic Therapy: Plausible Attraction. Committee for Skeptical Inquiry.
4. Park, R ‘Magnet Therapy: What’s the attraction?’ Washington Post. September 9, 1999.
5. Martel, GF, Andrews, SC, Roseboom, CG ‘Comparison of static and placebo magnets on resting forearm blood flow in young, healthy men’. Journal of Orthopaedic and Sports Physical Therapy. 2002;32(10):518-524.
6. Ramey, DW ‘Magnetic and electromagnetic therapy’. Scientific Review of Alternative Medicine 1998: 2 (1): 13-19.
7. Bassett, CA ‘Fundamental and practical aspects of therapeutic uses of pulsed electromagnetic fields (PEMFS)’. Critical Review of Biomedical Engineering. 1989: 17 (5): 451-529. 8. McCarthy, CJ, Callaghan, MJ and Oldham, JA ‘Pulsed electromagnetic energy treatment offers no clinical benefit in reducing the pain of knee osteoarthritis: a systematic review’. BMC Musculoskeletal Disorders. 2006: 7: 51.
9. Hulme, JM, Judd, MG, Robinson, VA, Tugwell, P, Wells, G, de Bie, RA ‘Electromagnetic fields for the treatment of osteoarthritis’.The Cochrane Library (Oxford) ** 2005;(2): (ID #CD003523). 2002.
10. Voznesensky, S ‘A possible case of selection bias? Pulsed electromagnetic energy treatment offers no clinical benefit in reducing the pain of knee osteoarthritis: a systematic review’.BMC Musculoskeletal Disorders. 2006: 7: 51.
11. Trock, DH, Bollet, AJ, Dyer, RH, Fielding P, Miner, WK, Markoll, R ‘A double blind trial of the clinical effects of pulsed electromagnetic fields in osteoarthritis’ Journal of Rheumatology 1993; 20:456-460.
12. Trock, DH, Bollet AJ, Markoll R. ‘The effect of pulsed electromagnetic fields in the treatment of osteoarthritis of the knee and cervical spine. Report of randomized, double blind, placebo controlled trials’. Journal of Rheumatology1994; 21:1903-1911.
13. Johnson, MT, McCullough, J, Nindl, G, et al. ‘Autoradiographic evaluation of electromagnetic field effects on serotonin (5HT1A) receptors in rat brain’. Biomedical Sciences Instrumentation. 2003;39:466-470.
14. Ryczko,MC, Persinger, MA ‘Increased analgesia to thermal stimuli in rats after brief exposures to complex pulsed 1 microTesla magnetic fields’. Perceptual and Motor Skills. 2002;95(2):592-598.