SALIVA ELECTROLYTES AS A USEFUL TOOL FOR ANAEROBIC THRESHOLD DETERMINATION

The purpose of the present study was to determine the anaerobic thresh old by analysis of changes in saliva composition during an incremental exercise test on a cycle ergometer. Thirteen healthy males underwent a submaximal test with an initial load of 50 W and load increases of 5 0 W per 3 min, until capillary blood lactate exceeded 4 mmol . l-1. A maximal test for maximum O2 uptake (VO2max) determination (initial loa d of 100 W and load increases of 50 W per 2 min) was also performed. S aliva and blood samples were obtained only in the submaximal test. Sal iva threshold (Th(sa)) was defined as the point at which the first inc rease in either Cl- or Na+ occurred. Catecholamine threshold (Th(ca)) was defined as the point at which a nonlinear increase occurred in eit her adrenaline or noradrenaline. The lactate (Th(la)) and ventilatory (Th(ve)) thresholds were determined according to published criteria. N o significant differences were found between Th(sa) values and the oth er methods of threshold determination. A high correlation was found be tween Th(sa) and Th(la) (r = 0.82, P < 0.01), and Th(sa) and Th(ca) (r = 0.75, P < 0.05). These results support the validity of Th(sa) as a new method for noninvasive determination of the anaerobic threshold.