Salivary total protein as a biomarker of anaerobic threshold in elderly athletes subjected to an incremental physical test

This study aimed to verify whether salivary total protein (STP) would reflect anaerobic threshold in elderly athletes subjected to an incremental exercise test. Methods: Seven elderly elite athletes (EEA) and six physically active elderly men (PAE) completed a treadmill protocol in which blood and saliva samples were collected. Results: Blood lactate (BL) and STP increased significantly in EEA during the test (0.8 ± 0.2 to 5.1 ± 2.0 mmol/L and 42.5 ± 7.5 to 222.5 ± 63.8 mg/dL, respectively) and remained elevated at five minutes after exercise (5.0 ± 1.9 mmol/L and 147.2 ± 50.0 mg/dL, respectively). Furthermore, correlations between STP and heart rate (r = 0.87, p < 0.001), and between BL and STP (r = 0.96, p < 0.001), were observed in the elderly athletes. Conclusions: STP represents a potential non-invasive biomarker for determining anaerobic threshold during an incremental exercise test, and this parameter may be used as an indicator of physical exercise intensity in elderly athletes.