Exercise and gut immune function: evidence of alterations in colon immune cell homeostasis and microbiome characteristics with exercise training

There is robust evidence that habitual physical activity is anti‐inflammatory and protective against developing chronic inflammatory disease. Much less is known about the effects of habitual moderate exercise in the gut, the compartment that has the greatest immunological responsibility and interactions with the intestinal microbiota. The link between the two has become evident, as recent studies have linked intestinal dysbiosis, or the disproportionate balance of beneficial to pathogenic microbes, with increased inflammatory disease susceptibility. Limited animal and human research findings imply that exercise may have a beneficial role in preventing and ameliorating such diseases by having an effect on gut immune function and, recently, microbiome characteristics. Emerging data from our laboratory show that different forms of exercise training differentially impact the severity of intestinal inflammation during an inflammatory insult (for example, ulcerative colitis) and may be jointly related to gut immune cell homeostasis and microbiota–immune interactions. The evidence we review and present will provide data in support of rigorous investigations concerning the effects of habitual exercise on gut health and disease. The February 2016 issue contains a Special Feature on the Effects of exercise on the immune system and metabolism coming into the Olympic year. The role of the immune system in exercise is complex and challenging. Too little exercise can depress the immune system. In contrast, too much exercise can also lead to a compromised immune system. This is a challenge that athletes face as they prepare for competition. Immunology & Cell Biology thanks the coordinators of this Special Feature ‐ Mark Febbraio and Graeme Lancaster ‐ for their planning and input.