PORTLAND, Ore. -- With the medical-magnet market growing by leap and bounds—said to be as high as $300 million in the U.S. and $5 billion worldwide--claims of medical efficacy range from curing carpal tunnel syndrome to eliminating arthritic pain. Unfortunately, no scientific study has yet to verify any of these claims. Time-varying electromagnetic fields have been scientifically verified to have positive medical effects--such as curing cancer in rats--but the static fields generated by the bracelets for wrists and ankles, and the pads for the back and feet, have never been properly scientifically tested.
Now, researchers at the University of Virginia have made the world's first scientifically verified claim for positive medical benefits from static magnetic fields, albeit the most useful medical application found by the researchers is not one claimed by bracelet and pad makers.
The new study set out to prove whether or not a static magnetic field could cause constricted blood vessels to dilate, thereby increasing blood circulation--a common claim made by companies selling magnetic therapies. What the researchers found was that the magnetic fields do, in fact, reverse constriction to dilation, as magnetic therapists claim, but more important, the magnets also caused the opposite effect: dilated blood vessels constricted. The latter--constricting dilated blood vessels--has valid medical applications in reducing inflammation after injuries, according to the study that was conducted by Professor Thomas Skalak, a University of Virginia biomedical engineer, along with his former student, Cassandra Morris, a doctoral candidate in biomedical engineering.
Once the scientists discovered that magnetic fields can also constrict dilated blood vessels, they concentrated their study on the valid medical application of reducing inflammation after injuries, rather than the milder medical effect of blood-vessel dilation to improve circulation. According to Skalak and Morris, a static magnetic field can significantly reduce swelling when applied immediately after an inflammatory injury. If suitable magnetic bandages could be designed into the ice-packs and compression wraps used today to reduce swelling, they could significantly shorten recovery time after injuries involving inflammations, according to Skalak and Morris.
"If an injury doesn't swell, it will heal faster," said Skalak. "The [injured] person will experience less pain and have better mobility [during recovery]."
Skalak and Morris used magnets of 70 milliTesla (MT)--about 10-times as strong as ordinary "refrigerator" magnets--which they placed near blood vessels in rats that had been treated with an inflammatory chemical. By measuring the diameter of blood vessels before and after exposure to the magnetic field, the researchers were able to confirm that the dilated blood vessels causing swelling in the inflamed tissues could be significantly constricted, thereby reducing swelling and speeding recovery.
The researchers are now pursuing commercial partners to create a line of magnetic bandages that could be used by athletes to reduce swelling--such as inside the baseball pitcher's ice-pack, which he now uses on his arm after games. Magnetic bandages could also become standard equipment in doctors' bags, school infirmaries and retirement-center clinics, according to Skalak and Morris.
Currently, the researchers are preparing clinical trials in humans, starting with elite athletes, to determine the proper dosage to reduce tissue swelling, as well as to engineer specific magnetic bandage form-factors for use on areas of the body that commonly heal slowly due to swelling.
"These are very widespread applications," said Skalak. "They will make a positive difference for human health."
This research was funded by the National Institutes of Health's National Center for Complementary and Alternative Medicine.