THE EFFECT OF EXERCISE ON SALIVARY LACTATE, ALPHA-AMYLASE AND URIC ACID IN HEALTHY VOLUNTEERS

Monitoring the training load of an athlete is an important aspect to improve their performance as well as to minimize the risk of non-functional overreaching, injury, and illness. To date, several external (e.g. time-motion analysis) and internal (e.g. blood lactate) parametersare currently used to monitor the effectiveness of a specific training load. The main drawbacks of biochemical analyses, required for monitoring specific biomarkers, are the need to collect venous blood samples, making this approach uncomfortable for many athletes.The use of oral fluid in the monitoring of athletes is an attractive approach because this technique is less invasive and unsafe. As a consequence, oral fluid samples may be collected several time from one subject, allowing a sortof real-timemonitoring during and after physical tests, training or competitions. Nevertheless, taking into the account the analyte to be quantified, oral fluid analysis requires a standardizationof the collection procedures in order to compare data from different coaches and supporting staff. The aims of this work was to i) evaluate the influence of sampling procedures on the quantification of alpha-amylase, lactate and uric acid in oral fluid samples and ii) determine if the analysis of these biomarkers can be used as an alternative indicator of the exercise intensity. For this purpose, ten healthy volunteers (5 females and 5 male) underwent incremental exercise on a cycle ergometer,at constant 70 rpm, with increment of about 20 W everythree minutes until voluntary exhaustion or impossibility to maintaincurrent workload. Stimulated oral fluid samples were collected 5 minutes before the exercise, every 3 minutes during workload and 10, 30and 40 minutes after the end of the test. Peripheral capillary oxygen saturation (SpO2) and heart rate values were continuously monitored during all the entire experiment. The concentrations of lactate and uric acid are influenced by the flow rate, since these two compounds do not diffuse through the salivary membrane due to their low hydrophobicity. Pearson’s correlation highlighted a good relationship (r = 0.6, p < 0.01) between heart rate and alpha-amylase activity in oral fluid. Lactate and uric acid levels increased during the exercise as a consequence of the increase of work load, whereas a sharp decrease, approaching baseline values, of these two compounds was observed in the recovery phase