A comparison of oral microbiome composition between highly trained competitive athletes and untrained controls

Background The oral microbiome has a crucial role in nitric oxide (NO) production and contributes to oral and systemic health. This study compared oral microbiome composition and markers of NO production between highly trained competitive athletes and inactive controls. Materials and Methods Ten competitive athletes and untrained controls were recruited. Saliva, plasma, supragingival plaque and the tongue dorsum microbiome were sampled. The microbiome was examined using long-read 16S rRNA sequencing and ozone-based chemiluminescence used to measure nitrate (NO ₃ ^- ) and nitrite (NO ₂ ^- ) levels. ^{Weekly training duration was recorded and aerobic fitness capacity (V̇O _2max ) assessed via maximal exercise testing. Results The beta-diversity of the tongue dorsum microbiome differed between groups (Adonis p= 0.046) and athletes had a higher relative abundance of NO ₃ - -reducing Rothia mucilaginosa and unclassified Gemella species. No significant differences were detected in the supragingival plaque. Positive correlations were detected between R. mucilaginosa and unclassified Gemella species and aerobic fitness. Athletes had higher levels of salivary NO ₃ - ( p =0.003) and NO ₂ - ( p= 0.03) . Conclusions Exercise training may impact the tongue dorsum microbiome more than supragingival plaque, with the relative abundance of specific health-assocaited bacteria higher in the tongue dorsum microbiome of athletes. Further research is needed to explore mechanistic links between the oral microbiome, exercise, and human health.}