Running Marathons or Longer Impacts The Body's Immune System

Running Marathons or Longer Impacts the Body's Immune System


A new study has just come out corroborating what many of us may already know. That is, running marathons, ultras, and long distances has a significant impact upon the body's immune response system. In this study, the authors looked at the impacts of running a standard marathon on lymphocyte and neutrophil selected functions. A lymphocyte is one of the two major types of white blood cells in body. The other are neutrophil granulocytes. Together, these cells are the first responders to inflammation, injury, cancer, and other types of immune-related functions in the human body. The authors found that there was a significant decrease in in lymphocyte and neutrophil function post marathon, and that this decrease in function resulted in an impairment in acquired immunity. So basically, after long runs, marathons, or ultras the body is in a state of impaired acquired immunity and more susceptible to infections, colds, and increased inflammation. Therefore, when recovering from such runs, it is important to keep this in mind. Not only do we need to replenish our fuel stores, but we need time to allow our body to recover its acquired immunity prior to stressing it again. How long this takes is still unknown, but with a decrease in some lymphocytes by 50%-80%, it could be mean several days to a week or more.

Ran my standard 15K loop yesterday. Tied my PR of 1:18, which was surprising since I spent 7 hours on my feet previous to running. I had some mountain bikers pass me on the way back, which might have helped me push the pace above what I was feeling like running.