Ultra-Endurance triathlon competition shifts fecal metabolome independent of changes to microbiome composition

Gregory J Grosicki, Jamie Pugh, Laura Wosinska, Karina Quilter, Darragh Mattimoe, Jacob Allen, Susan A Joyce, Orla O’Sullivan, Graeme L Close

Research output: Contribution to journalArticlepeer-review


Understanding changes to gut microbiota composition and metabolic output in response to acute exercise may be necessary for understanding the mechanisms mediating the long-term health and performance benefits of exercise. Our primary objective was to characterize acute changes in the fecal microbiome and metabolome following participation in an ultra-endurance (3.9 km swim, 180.2 km bike, 42.2 km run) triathlon. An exploratory aim was to determine associations between athlete-specific factors [race performance (i.e., completion time) and lifetime years of endurance training] with pre-race gut microbiota and metabolite profiles. Stool samples from 12 triathletes (9 males/3 females; 43 ± 14 yr, 23 ± 2 kg/m 2) were collected 48 h before and the first bowel movement following race completion. Intra- and inter-individual diversity of bacterial species and individual bacterial taxa were unaltered following race completion (P > 0.05). However, significant reductions (P < 0.05) in free and secondary bile acids [deoxycholic acid (DCA), 12-keto-lithocholic acid (12-ketoLCA)] and short-chain fatty acids (butyric and pivalic acids), and significant increases (P < 0.05) in long-chain fatty acids (oleic and palmitoleic acids) were observed. Exploratory analyses revealed several associations between pre-race bacterial taxa and fecal metabolites with race performance and lifetime history of endurance training (P < 0.05). These findings suggest that 1) acute ultra-endurance exercise shifts microbial metabolism independent of changes to community composition and 2) athlete performance level and training history relate to resting-state gut microbial ecology.

Original languageEnglish (US)
Pages (from-to)549-558
Number of pages10
JournalJournal of Applied Physiology
Issue number3
Early online dateAug 17 2023
StatePublished - Sep 1 2023


  • endurance exercise
  • triathlete
  • physical activity
  • microbiome
  • Ironman

ASJC Scopus subject areas

  • General Medicine


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