A Method for the Evaluation of Anaerobic Threshold Based on Heart Rate Dynamics during Incremental Exercise Test and Recovery

Resumo

A new graphical method for determining the anaerobic threshold (AT), which has been experimentally tested in testing the maximal aerobic capacity in 46 cyclic sports athletes (mean age, 20.3 ± 3.6 years; body weight, 68.3 ± 10.4 kg). The gas exchange indices, the heart rate, the time of onset (from the beginning of the test) of AT by pulmonary gas exchange ratios, the non-metabolic CO₂ excess, the concentration of lactate in capillary blood, and the time of onset of AT determined by the proposed graphical method by the parameters of the pulsogram obtained during the test and 10-min recovery were determined. Two different protocols of load change—the incremental ramp test on a treadmill and the incremental step test on a bicycle ergometer—were used. Regardless of the protocol and the load type, statistical analysis revealed no significant differences between the results of AT measurements in the same athletes by the gas exchange and lactate dynamics indices, on the one hand, and by using the graphical method by the pulsogram parameters, on the other hand. In the test with a stepwise increase in load on a bicycle ergometer, as well as in the test with a smoothly increasing load on a running treadmill, the indices obtained at the AT that was determined by using the graphical method highly correlated with the indices obtained at the AT that was determined by analyzing the dynamics of pulmonary ventilation, non-metabolic CO₂ excess, and lactate concentration (p < 0.05). The proposed method does not require the use of sophisticated equipment and invasive procedures and can be widely used in sports and fitness practice.