Massage's healing touch may have more to do with DNA than with good hands. A new study has revealed for the first time how kneading eases sore muscles—by turning off genes associated with inflammation and turning on genes that help muscles heal. The discovery contradicts popular claims that massage squeezes lactic acid or waste products out of tired muscles and could bring new medical credibility to the practice.
Despite massage's widespread popularity, researchers know surprisingly little about its effects on muscles. Past studies have managed to show only that a well-administered rub can reduce pain, but none has ever pinpointed how. The scant evidence makes many physicians unsure, if not outright skeptical, of the method.
Mark Tarnopolsky, a neurometabolic researcher at McMaster University in Hamilton, Canada, was one of those physicians—until he suffered a severe hamstring injury in a waterskiing accident 4 years ago. Massage therapy was part of his rehabilitation regimen, and it was so effective at easing his pain that he became determined to track down the mechanism that made him feel so good. "I thought there has to be a physiologic basis for this," he says. "And being a cellular scientist, my interest's in the cellular basis."
So Tarnopolsky and colleagues—including the coordinator of his rehab program—recruited 11 young men willing to exercise in the name of science. The subjects underwent a grueling upright cycling session that left their muscles damaged and sore. Ten minutes after their workout, a massage therapist massaged one of their legs. Meanwhile, the researchers took tissue samples from the volunteers' quadriceps muscles—once before the workout, once 10 minutes after the massage, and once 3 hours after the workout—and compared the genetic profiles of each sample.
The researchers detected more indicators of cell repair and inflammation in the post-workout samples than in the pre-workout samples. That didn't surprise them because scientists know that exercise activates genes associated with repair and inflammation. What did shock them were the clear differences between the massaged legs and the unmassaged ones after exercise. The massaged legs had 30% more PGC-1alpha, a gene that helps muscle cells build mitochondria, the "engines" that turn a cell's food into energy. They also had three times less NFkB, which turns on genes associated with inflammation.
The results, published online today in Science Translational Medicine, suggest that massage suppresses the inflammation that follows exercise while promoting faster healing. "Basically, you can have your cake and eat it too," Tarnopolsky says. He adds that the study found no evidence to support often-repeated claims that massage removes lactic acid, a byproduct of exertion long blamed for muscle soreness, or waste products from tired muscles.
"This is probably the best study I've seen that looks at the biological basis for massage therapy," says Thomas Best, a sports medicine physician at Ohio State University in Columbus, who has studied massage's effects on animals. He notes that it would be a hard experiment to reproduce because no two massages are identical, but he calls the results "compelling" nonetheless.
Tarnopolsky, for one, is a convert. "There's no question I'm going to be visiting the massage therapist more often," he says.