One size won't fit all. Skalak said it would take a much stronger magnet, for example, to treat a thigh muscle than a sprain in the small finger. And, as he pointed out often during the interview, no one knows yet if it will work at all in humans.
But Skalak sounds optimistic, based on many years of experience in a relatively narrow field. He is an expert on the smallest blood vessels in the body, ranging from five to 200 microns in diameter, or about one fifth of a millimeter.
"These are very small blood vessels, and they are in all the tissues in your body," he said. "We like to think that's where the action is. That's where oxygen gets delivered, and it's where waste products get removed from your tissues.
"These small arterials can open and close because they have a layer of smooth muscle wrapped around them," he added. "They can increase their diameter, thus delivering more flow to a given tissue, and they can decrease the diameter, just like opening and closing a garden hose changes the flow of water."
When a magnetic field was applied to the paws of the lab rats, the vessels that had been dilated constricted, and the constricted vessels dilated, suggesting that the magnetic field "induced vessel relaxation in tissues with constrained blood supply, ultimately increasing blood flow."
The mechanism is not fully understood, he added, but he suspects the magnetic field alters the flow of positively charged calcium ions that interact with the muscles around the small blood vessels, causing them to dilate or constrict.
Skalak worries that his study will be taken out of context and used to boost sales of magnetic gizmos that are not supported by medical evidence. He's probably right.
Magnets are attractive to many, and their use has been widespread for several centuries. Early believers thought magnets might pull diseases and pain from the body, a belief that persists to this day, despite the lack of evidence.
However, magnets have proved to be a valuable tool in medicine for a wide variety of uses. A number of researchers are developing techniques to use small magnets to draw chemotherapy-carrying magnetic particles into tumors and hold them there, thus killing cancerous cells while sparing nearby healthy cells.
And magnets are at the heart of one of modern medicine's most useful techniques, magnetic resonance imaging. This device gives doctors precise images of the entire human body in amazing detail.
But it's no simple contraption, and it's not your ordinary magnet. The strength of a magnetic field is measured in gauss. Earth's magnetic field, measured at the equator, is .2 gauss. An MRI is up to 30,000 gauss.
So magnets, like human injuries, come in many complex forms. Skalak hopes his work will lead to magnets that can be used on a very personal level, proving the ancients got it at least partly right.