If your workouts aren’t making you sore anymore you might want to consider the possible reasons why. Not that you would even want to experience intense all over soreness all the time, but if you’ve ever wondering why exactly it tapers down researchers now have the answer.
Some researchers at Brigham Young University refer to that reduction in soreness as the “repeated bout effect.” It’s still not entirely clear why this happens, but they have some insights into why it does. When we do a new workout we are making small tears in our muscle fibers which is what helps them to grow as they repair. But it’s our immune system that is actually going to work on those repairs and it tries to ensure that we don’t experience further damage to the body.
It’s specifically our T-cells that are helping to repair our muscles, which are a type of white blood cell that comes from the thymus gland. According to the study author Robert Hyldahl:
“You think of T-cells as responding to infections, not repairing muscles—but we found a significant accumulation of T-cells infiltrating damaged muscle fibers. Our study is the first to show T-cells present in human muscle in response to exercise-induced damage.”
The study required the fourteen participants to do a series of workouts spaced out over a period of four weeks. They performed their exercises on a isokinetic dynamometer machine which has the ability to take and record measurements of how hard certain muscle groups are working. Before and after each round of exercising the researchers took biopsies of their body tissue to see the concentrations of blood cells in the muscles.
The researchers were surprised to find that there were T-cells in there along with the rest of the white blood cell increase. They only specifically looked for the T-cells at all because one enterprising undergraduate student suggested that they do so.
According to another study author Michael Deyhle:
“T-cells, up until recently, were not thought to enter healthy skeletal muscle. We hadn’t planned on measuring them because there’s no evidence that T-cells play a role in infiltrating damaged muscle tissue. It’s very exciting.”
This points to the idea that the muscles actually remember that the damage has occurred before and therefore react more quickly to handling it with more immune cells. The body essentially just reacts similarly to the way it would if it was dealing with bacteria, a virus, or toxins that it has come into contact with before.
Interestingly they also found that the inflammation actually goes up after a second round of exercise on the same body part, which is the opposite of what they believed before. Meaning those anti-inflammatory medicines might not help with soreness after all.
“Some people take anti-inflammatory drugs such as Ibuprofen and Aspirin after a workout, but our study shows it may not actually be effective. The inflammation may not be directly causing the pain, since we see that muscle soreness is reduced concurrent with increases in inflammation.”
Good to know.