I have been looking at the connections between chronic low-grade inflammation and exercise. For any type of condition related to chronic inflammation, exercise is usually prescribed. Low-intensity exercise, like walking, makes sense because it can help to ultimately lower inflammation. However, high-intensity exercise is now being prescribed more regularly for inflammatory conditions.
Something about this doesn't seem right to me. If you start from a state of low-grade inflammation, how will adding on the (temporary) inflammation from high-intensity exercise help?
I realize that there is evidence showing that high-intensity exercise can reduce inflammation. However, the overall evidence is mixed. This major review done last year concluded that:
"In patients with a chronic inflammatory disease, both acute and chronic exercise might elicit different inflammatory responses (i.e., exaggerated after acute exercise & attenuated after training) compared to healthy matched controls. However, the results reveal a major gap in our knowledge regarding the effects of acute and chronic exercise on inflammatory markers in patients with a chronic inflammatory disease. Results are often inconsistent, and differences in training programs (intensity, frequency and duration), heterogeneity of disease populations studied, and analytic methods may be just some of the causes for these discrepancies."
In other words, the research is not definitive on any of this.
Another issue related to all this is how inflammation affects the person's response to an exercise protocol. Low-grade inflammation can hinder the body's response to exercise. For example, this study showed that those subjects who started with the lowest levels of inflammation gained the most muscle strength over a 12 week period. On the opposite end, this study showed that those with the highest baseline inflammatory markers lost the most strength and muscle over the following 5 years.
With inflammation and high-intensity exercise, I think some people are putting the cart before the horse. It may be better to first work on lowering inflammation, mostly through diet and light exercise, and then add in high-intensity exercise once the inflammation is lowered. Adding heavy exercise-induced inflammation on top of low-grade chronic inflammation may actually make things worse in the long run.
