Endocrine Abstracts

Anaerobic threshold (AT) is defined as the point of maximum intensity at which lactate is being produced but does not accumulate in blood during exercise. Training at this intensity is common in athletes. Lactate is currently regard as indicator of effort intensity. It is usually quantified by reflectometry of capillary blood. This procedure although not very invasive, may be annoying during repeated measurements. Saliva is proposed as an alternative sample.

The objective of the present study is to quantify the variation of salivary lactate levels during AT training, in order to prove its usability in this field.

10 male subjects (32±2.96 years) performed a treadmill test recording intensity (watts/min), VO2 and heart rate (HR) to determine AT. After two days resting they performed 6 running series of 1km at AT rhythm with 2 minutes of resting between series. Saliva samples by Salivette system (SARSTEDT, Germany) and HR were taken at pretest, the end of each series, and 3, 6 & 9 min of resting after. Eating, smoking, drinking (except water) or teeth brushing was forbidden in 2 h previous to start.

Salivary lactate concentrations increased significantly from 1st to 3rd series (P=0.002). Afterwards, a plateau of saliva lactate concentration was observed in all subjects up to the end of the series (4th–6th). After a small reduction, an additional increase in saliva lactate was also consistently observed after 6 min of rest. HR hardly changed during the exercise series. Since we can conclude that: The salivary lactate was increased according to the accumulated workload despite exercise was performed at constant intensity (AT). That was confirmed because the heart rate (HR) hardly changed at this constant rate. Since, saliva lactate levels in an AT training are independent of heart rate and mostly of effort intensity.