Effect of Post-Exercise Sauna Bathing on Targeted Gut Microbiota and Intestinal Barrier Function in Healthy Men: A Randomized Controlled Trial

Abstract

Background: Body temperature fluctuations induced by acute exercise bouts may also influence the intestinal barrier with related effects on epithelial permeability, immune responses, and release of metabolites produced by the gut microbiota.To evaluate the combined influence of 4-weeks exercise training and post-exercise sauna treatments on gut bacteria and fungi, inflammation, and intestinal barrier function. Methods: Randomized, parallel group design with pre- and post-study measurements.Fifteen (15) untrained males aged 22±1.5 years were randomly assigned to exercise training (ET) with or without post-exercise sauna treatments (S). Participants in the group ET+S (n=8) exercised 60 minutes, 3 times per week, on a bicycle ergometer followed by a 30-minute dry Finish sauna treatment. The control group (ET, n=7) engaged in the same exercise training program without the sauna treatments. Blood and stool samples were collected before and after the 4-week training program. Blood samples were analysed for the concentration of high-sensitivity C-reactive protein (hsCRP) and complete blood counts. Stool samples were analysed for pH, quantitative and qualitative measures of targeted bacteria and fungi, zonulin, and secretory immunoglobulin A. Group comparisons showed no significant differences for blood and stool sample measurements during the 4-week study.Results: Group comparisons showed no significant differences for blood and stool sample measurements during the 4-week study.Conclusions: The combination of 4-weeks exercise training and post-exercise sauna treatments did not have a measurable influence on targeted gut microbiota, intestinal barrier function, and inflammation biomarkers in young males compared to exercise training alone.