Determination of the maximum steady state of lactate (MLSS) in saliva: An alternative to blood lactate determination

Based on previous research which shows parallelism between the saliva and b lood lactate response during incremental exercise, we hypothesized that a " maximum salivary lactate steady state" (saliva-MLSS) might exist. Thus, the aim of the present investigation was to establish 1) which lower limit for the increase in salivary lactate concentration during a constant workload (i.e., from the 10th to the 20th min) test could be used to determine the s aliva-MLSS and 2) if the exercise intensity corresponding to the saliva-MLS S is identical to that evoking the (blood) MLSS. Twelve male amateur athlet es of mean (+/-SD) age 24+/-5 year were selected for the study. Based on th e results of a previous maximal cycle ergometer test for lactate threshold (LT) determination, each subject performed consecutive constant workload te sts of 20-min duration on separate days for MLSS determination, Blood and s aliva (25 mu l) samples were collected at 0, 10, and 20 min during the test s for lactate determination. A Student's t-test for paired data demonstrate d that a salivary lactate increase of 0.8 mM corresponded to the saliva-MLS S. At this value, indeed, no significant differences were observed between the mean (V) over dot O-2, and W values corresponding to the MLSS and the s aliva-MLSS. In conclusion, the present findings indicate that 0.8 mM is the lower limit for the increase in saliva lactate concentration during a cons tant load test and thus is that which might be used as a reference to deter mine saliva-MLSS. Furthermore, saliva-MLSS might be used as an alternative to MLSS determination in blood samples.