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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Dr. Zorba Paster: Is icing sore muscles counterproductive? Jury is still out

By Dr. Zorba Paster For The Spokesman-Review

You’ve probably been told it. I know I have, and so have my kids. Their soccer coaches were ready, willing and able to provide ice right after an injury. We’ve been told for years, and I’ve been telling folks for years, ice after exercise and an injury is the way to go. But a new study shows that this might not be the best thing to do. It’s a mouse study.

Now I know you’re just rolling your eyes at mice. How can we learn anything from mice, but bear with me for just a moment. In this study published in the March Journal of Applied Physiology, researchers at Kobe University in Japan and other institutions interested in muscle physiology took 40 young, healthy mice and electrically stimulated their lower legs repeatedly, simulating what a prolonged gym or soccer workout would be.

Now contracting muscles, in all animals, have a similar physiology. The mouse muscle is in many respects just like the human muscle. And mice, as you can imagine, run around all night long looking for food. They are working out all the time – undoubtedly better than the best gym work that most of us do.

And just like our muscles that stretch and contract, overloading strenuous activity can damage them. These scientists were interested in the healing activities and how they ice affected them. For half the mice, they attached ice immediately after the prolonged activity while the other half remained without ice.

Over the next few weeks, they collected muscle samples from both groups trying to see what ice did to muscles that are regularly overexerted. What interested them most was what inflammatory cells and cytokines were around, as these are the tiny little guys that heal us all the time. They run into the injured parts of our body mopping up debris and ramp up the chemicals we need to heal us, thereby promoting new healthy tissues.

First off, let’s look at the mice without ice. They saw clear damage to the muscle fibers, as expected, and they saw evidence of those helper inflammatory cells and cytokines, just as predicted. And within hours, the little tykes were removing the cellular debris, and within three days the damaged muscle fibers were cleared away. Gone. Removed. So new fibers could grow and prosper.

Not so for the iced muscles. For them, healing was remarkably delayed. They took more than twice as long, seven days, to reach the same healing as the unchilled muscles. And even after two weeks, they did not have the same complete healing.

We ice muscles for pain control. It helps. In 2011, a study of athletes who had torn calf muscles found that iced muscles had nearly as much pain as non-iced muscles. And they didn’t return to their sport any quicker. Then there was a weight-training study that showed that men who applied ice packs after workouts actually developed less muscular strength, size and endurance than those who were without ice.

The idea behind ice packs is that it stimulates your sympathetic nerve fibers, reducing swelling by signaling your blood vessels to constrict. This rush of blood away from your injury reduces swelling and the concurrent inflammatory response. The idea is less swelling, less pain and better recovery. It all makes sense. But what makes sense might still not be the best thing you can do.

My spin: We have a long way to go when it comes to figuring out the best way to go after sports injuries. This new mouse study points out that ice might be counterproductive. These mice were exercised day in and day out – when humans exercise, when we injure ourselves, we usually stop and wait until the pain goes away. These mice didn’t have that prerogative.

Dr. Zorba Paster is a family physician and host of the public radio program “Zorba Paster on Your Health.” He can be reached at askzorba@doctorzorba.com.