Comparative Analysis of Gut Microbiota in Collegiate Swimmers Following Changes in Exercise

Exercise can
influence gut microbial community structure and diversity; however, the
temporal dynamics of this association have rarely been explored. Here we
characterized fecal microbiota in response to short term changes in training
volume. Fecal samples, body composition, and training logs were collected from
Division I NCAA collegiate swimmers during peak training through their
in-season taper in 2016 (n = 9) and 2017 (n = 7), capturing a systematic
reduction in training volume near the conclusion of their athletic season.
Fecal microbiota were characterized using 16S rRNA V4 amplicon sequencing and
multivariate statistical analysis, Spearman rank correlations, and random
forest models. Peak training volume, measured as swimming distance, decreased
significantly during the study period from 32.6 ± 4.8 km/wk to 11.3 ± 8.1 km/wk
(ANOVA, p < 0.05); however, body composition showed no significant
changes. Coinciding with the decrease
in training volume, the microbial community structure showed a significant decrease
in overall microbial diversity, a decrease in microbial community structural
similarity, and a decrease in the proportion of the bacterial genera Faecalibacterium and Coprococcus. Together these data
suggested changes in training volume significantly influence the gut
microbiome; future research will establish whether these changes are associated
with energy balance or nutrient intake.