Impact of Salivary Amino Acid Concentrations on 8 km Running Performance in Male Undergraduate Students: A Prospective Observational Study Based on HPLC

Purpose: To explore the potential relationship between salivary amino acid concentrations and 8 km running performance in male undergraduate students. Methods: Thirty male undergraduate students were recruited. Participants completed an 8 km run while wearing smart bracelets. Saliva samples were collected before, immediately after, and 24 h after the run. Ultra-High Performance Liquid Chromatography (UHPLC) was used to quantify salivary amino acids. Results: The fast group (average speed > 12.80 km/h) had a significantly shorter running time (35.66 ± 1.30 min,p< 0.001) and higher speed (13.59 ± 0.46 km/h,p< 0.001) than the slow group. Before the run, salivary serine concentration (20.19 µg/mL,p= 0.013) was higher in the fast group. After 24 h, salivary glutamine concentration (6.65 µg/mL,p= 0.047) was lower in the fast group. Salivary threonine concentration was positively correlated with running speed. For every 1 µg/mL increase in salivary threonine concentration, average running speed increased by 0.011 km/h, and this correlation persisted after adjusting for age and heart rate. Conclusions: This study found a positive correlation between salivary threonine and 8 km running speed, along with differences in serine and glutamine concentrations among runners with different speeds. These findings provide preliminary evidence for the relationship between salivary amino acid concentrations and running performance, though further research with larger samples and diverse exercise types is needed.