Interesting reading Cliff ! That's probably another reason for feeling sluggish when I have sat around too much.

Exercise can positively impact the gut microbiome in several ways, including:
Increasing beneficial bacteria
Exercise can increase the number of different types of bacteria in the gut, including those that produce butyrate. These bacteria may help reduce inflammation, support the immune system, and improve brain function. For example, one study found that running on a treadmill for 30–60 minutes, three times a week, increased butyrate-producing bacteria in the gut.
Decreasing harmful bacteria
Exercise can also decrease the amount of "bad" bacteria in the gut, such as Proteobacteria.
Improving energy homeostasis
Exercise can positively impact energy homeostasis, a biological process that regulates energy production, expenditure, and food intake.
Increasing microbial diversity
Regular physical activity can lead to greater microbial diversity and the abundance of certain taxa that are responsive to exercise.

Exercise was interesting and not sure how it corelates.