A recent article featured on BBC highlights that the gut microbiome may have a greater role in the improvement of health through exercise than we previously thought. Our guts are alive with a vast diversity of microbial residents. Their roles range from fermenting dietary fibers, vitamin synthesis, and fat metabolism regulation to immune support against invading microbes and regulating inflammation. Patients suffering from obesity, but also cardiometabolic and autoimmune diseases, show a lower microbial diversity in their gut than the healthy gut. Other variables such as our genes, medications, stress, smoking or diet can also impact the gut microbiome. As our lifestyle choices shape our gut microbiome, there are actions we can take to improve our gut microbiome, such as consuming >30 different plant foods per week, or sleeping more to overcome stress. Exercise has many health benefits and gut microbiome improvement is no exception, but the exact mechanism behind this has been unknown. The first clue was observations from mice; exercising mice had less pro-inflammatory Turicibacter than sedentary mice. In another study, exercising rats had higher intestinal production of butyrate. Butyrate is known to provide fuel for gut cells and modulate gut permeability and inflammation. Another observation from mice illustrated that exercising mice harbored more Faecalibacterium prausnitzii, which is a known anti-inflammatory microbe. To confirm that these changes are relevant to the human gut microbiome, it makes sense to compare sedentary and athletic human gut microbiota. Past studies have shown an increase in gut microbial diversity in athletes compared to sedentary humans as well as exercise-linked increases in F. prausnitzii and butyrate production. Another study investigated stool and blood samples from people who exercised at moderate-to-vigorous intensity for 30-60 minutes 3 times a week and controlled for dietary effects through three diet control days prior to sampling. The study’s findings illustrated an increase in butyrate producers’ relative abundance regardless of body mass index. However, the beneficial effects of exercising on the gut emerged as reversible six weeks after exercising experiment in otherwise sedentary humans. Furthermore, another study compared sedentary and exercising Finnish type 2 diabetes or prediabetes patients. The exercising cohort of patients had increased Bacteroidetes, a group of bacteria crucial for digesting sugars and proteins and releasing anti-inflammatory molecules in the gut. Exercising also decreases Clostridium and Blautia abundances. Those genera of bacteria may be pro-inflammatory, aggravating the immune system. To read more on exercise and gut microbiome, please read the original article.