Work

Exercise affects salivary biomarkers of creatine metabolism in healthy adults

Year: 2025

Type: article

Abstract: We monitored changes in salivary creatine pre- and post-high-intensity exercise in young adults while also investigating the potential correlation between salivary and serum creatine levels. Saliva and serum samples were collected before and immediately after an incremental running-to-exhaustion treadmill test in fifteen young adults (mean age [23.9 ± 2.9] years, eight females), with samples analyzed for guanidinoacetic acid, creatine, and creatinine using a liquid chromatography–tandem mass spectrometry method. Following exercise, there was a substantial elevation in salivary creatine levels from (17.5 ± 14.2) μmol·L −1 to (43.6 ± 30.4) μmol·L −1 ( p < 0.001), coupled with a significant increase in salivary creatinine from (11.3 ± 5.8) μmol·L −1 to (17.0 ± 9.3) μmol·L −1 ( p = 0.04). In contrast, serum creatine levels were unaffected by exercise ( p = 0.80), while creatinine levels exhibited a strong tendency to decrease post-exercise (from [81.8 ± 17.5] μmol·L −1 to [73.1 ± 11.6] μmol·L −1 ; p = 0.06). A comparison of the slopes of the two regression lines (saliva vs. serum) revealed significant differences for both creatine ( p = 0.01) and creatinine ( p = 0.03). The above findings suggest a potential difference in the dynamics of creatine metabolites in these two bodily fluids, both pre and post-exercise.

Source: Sports Medicine and Health Science

DOI: 10.1016/j.smhs.2025.03.010