Running and the Immune System

Can running actually suppress your immune system?

By Ariel Stateman

The American Heart Association recommends getting at least 150 minutes of moderate-to-intense cardio each week. Cardio has so many benefits for both a person’s mental and physical health. Running can help prevent high blood pressure, increase bone density and physical strength, strengthen joints and your lungs, and help lose weight among countless others. Also, it can even stimulate your immune system. When a person runs, the body circulates protective cells (e.g. macrophages, natural killer cells, and other leukocytes) and proteins (e.g. immunoglobulins, also known as antibodies) of the immune system throughout the body at a faster rate. However, over-training can have a negative effect and suppress the body’s immune system.

Source: https://www.dietspotlight.com/benefits-of-running/

Research has found that over-trained runners experience a higher number of upper respiratory tract infections than people who don’t run. It is because the body enters an altered form of immunity after a person runs for longer than 90 minutes. This can last from 3 to 72 hours after a run, leaving your body exposed to many bacteria and viruses. The stress hormone, cortisol, is extremely high after strenuous runs which suppresses the immune system. Also, those protective cells I mentioned earlier are greatly reduced after heavy running.

Source: https://www.active.com/running/articles/how-to-run-a-sub-two-hour-half-marathon

So, what can you do if you training for a marathon or like to run long distances? Try to change up your workout. Distance running uses slow-twitch muscle fibers (type I). This is a type of skeletal muscle fiber; the other general type is fast-twitch muscle fiber (type II). Slow-twitch muscle fibers use the same fuel (simple sugars) as the immune system so you get this battle between your muscles and your immune system over who gets the fuel/energy. Your immune system is the one that loses and suffers. The trick is to also get your fast-twitch muscle fibers involved. Instead of running a long, slow run for over 90 minutes, try a medium-distance run incorporated with high-intensity interval training.

My main takeaway, running is extremely good for the body! Just try to keep it below 90 minutes a day and if you training for a marathon, take good care of your body and hygiene after running.

Author: Ariel Stateman

About the author -- Ariel Stateman is a former Research Assistant and mentee of the RIPLRT. She is currently a research associate in a laboratory within a higher education institution in the state of Illinois.