Changes in lactate, ferritin, and uric acid in saliva after repeated explosive effort sequences.

Background: The aim of the present study was to evaluate the changes in a panel of biomarkers including lactate, ferritin, and uric acid in saliva of untrained and trained subjects after repeated explosive effort sequences, and to analyze the differences in interpretation of these biomarkers depending on the way the data is expressed (without any correction or corrected by protein content or flow).

Methods: Eighteen volunteers (11 untrained and 7 trained) performed 8 consecutive explosive effort sequences (60-meters sprints). Blood and saliva samples were collected before and after each sequence. Salivary data was analyzed as absolute concentration and after correcting by their protein content and flow.

Results: Lactate in saliva showed increases with acute exercise, being these increases of higher magnitude in non-trained subjects. In addition, when corrected by total protein, lactate in saliva correlates with blood lactate in non-trained subjects. Ferritin and uric acid in saliva did not show changes after the effort sequences.

Conclusions: From the biomarkers evaluated, the measurement of lactate in saliva corrected by total protein could be useful for the assessment of fatigue induced during repeated explosive effort sequences and could be potentially used as a non-invasive alternative to blood lactate. This report also points out that way of reporting the saliva analytes could greatly influence the interpretation of the results and that lactate in saliva has a different dynamic in trained and non-trained individuals that should be further explored.