It's likely that you've encountered someone who swears by magnetic bracelets or shoe insoles as a reliable means of relieving everyday aches and pains. Even some professional atheletes have endorsed such products, claiming that magnets help mitigate the physical strain from playing tennis, golf, or football. You may have even wondered about these products yourself: muscle injuries can be annoying, after all, and many common over-the-counter pain relievers (such as Tylenol and Advil) have risks and side effects associated with their use.
But what about magnets? The claims sound solid at first, or at least worth considering -- after all, there is iron in the blood of every human being. Therefore, a magnet applied to a given part of the body might be able to increase circulation to that body part, right?
Here Comes the Science
Not exactly. The iron circulating in our blood is bound into hemoglobin molecules, which in turn are nestled within red blood cells. These individual iron atoms do not interact with the iron atoms in other hemoglobin molecules in the bloodstream: they are isolated and insulated. In a household magnet, such as your fridge poetry or the powerful, brittle magnets in your computer's hard drive, it is the net effect of numerous iron atoms acting in concert that produces the specialized, familiar properties of metallic iron. Therefore, sticking a magnet in your shoe will not cause blood to rush to your heel: the iron atoms in your discrete blood cells have no idea that they are supposed to be cooperating with one another!
Nevertheless, electromagnetic fields do interact with the human body, and there is some evidence that strong pulsed electromagnetic fields can in fact have some therapeutic benefit. For instance, researchers at Emory University attached powerful electromagnets to the heads of patients suffering from depression. These depressed patients reported marked improvement in mood and outlook. This type of treatment induces an electrical current in the brain itself, which apparently helps excite areas of the brain thought to be sluggish or underactive in depressed individuals. Magnet therapy for depression is somewhat similar in mechanism, then, to modern electroconvulsive therapy, or ECT. Some studies have also shown quicker healing in patients with broken bones when the affected areas are exposed to a strong pulsed field.
The thing to keep in mind here is that so far the only clinically effective use of magnets as a therapeutic aid have utilized fields of very short duration, and of a strength up to 10,000 gauss. Compare this with the static fields generated by popular "magnetic therapy" products that are at most a few hundred gauss.
The Baylor Study
A now-famous study cited by many magnet dealers to vindicate the use of small, static mangetic fields in the mitigation of pain was performed in 1997, at the Baylor College of Medicine in Houston, TX. Post-polio patients were divided into two groups, and each member of each group was given a "magnet" to hold against his or her skin for 45 minutes. This was supposedly a double-blind study: meaning that neither the doctors distributing the devices, or the patients themselves, knew whether they'd received a real or a fake magnet. To the astonishment of researchers, the group with the real magnets reported a greater subjective lessening of pain. These results have been cited by many as "proof that magnets relieve pain".
A double-blind setup is certainly a step in the right direction toward obtaining useful experimental data. However, this study was far from perfect. Worth mentioning is the fact that the members of the placebo group were, on average, four years older than those in the group that received real magnets (though supposedly, members of each group were selected randomly). In addition to this, no follow-up interviews were done with any of the patients, leaving room for doubt as to whether this therapy had any lasting benefit. The experiment consisted of a single 45-minute exposure to the magnets, rather than the multiple exposures spread scross several different groups that might have made the collected data a bit more convincing. Overall, the Baylor study was certainly interesting, but by no means justification for spending hundreds of dollars on chunks of iron to put in your shoes.
For Entertainment Purposes Only
The internet has been a boon to retail in more ways than one. Anyone can have a web site these days, and there is no organized regulatory body cracking down on false or misleading claims. Therefore, it is up to you, the consumer, to recognize ridiculous assertions and give them the only appropriate response: laughter.
One site sells a line of "magnetic beauty and health care" products, including something called Magnetic Energizing Shampoo. This shampoo apparently "Immerses your hair in microscopic domains of magnetism! I would greatly appreciate it if someone could please tell me what this statement is supposed to mean. The same site, in its "History of Magnetic Therapy Section", states that:"Ancient Egyptians used loadstones to prolong life and improve health."(sic)
Another site informs us that, "Ancient doctors theorize that magnets promote healing by stimulating blood flow to the affected area, bringing extra oxygen and nutrients while reducing toxins."
First of all, "ancient doctors" thought that mental illness could be cured by drilling a hole in the skull to release the demons. Malaria was not caused by mosquito bites, but by "breathing the night air".I don't know if I'd consider these ancient doctors trustworthy authorities. Second of all, the "reduces toxins" claim is a baloney meme that has been making the rounds on the alternative medicine circuit for years. Sticking a magnet to your leg will not in any way, shape, or form reduce any of the toxins in your body. If you are a member of the toxin crowd, remember that your body has its own excellent toxin-removal facility built right in. It's called the excretory system. Drink more water and eat your oatmeal.
I am not putting down those who swear by non-standard methods of healing. However, I am urging consumers to think carefully before spending money on the devices such as bracelets, inserts, and belts. Some of these specialized devices retail for over a hundred U.S. dollars. If there is anything to the idea that static magnets can reduce pain (beyond that of a placebo effect), you would be just as well served by using common household magnets (which you can get for pennies)!