THE RELATIONSHIP BETWEEN HEART RATE DEFLECTION POINT AND THE VENTILATORY ANAEROBIC THRESHOLD IN RUNNERS WHITH DIFFERENT AEROBIC CAPACITY

The purpose of this study was to examine the relationship between the heart rate deflection point (HR(DP)) and the gas exchange anaerobic threshold (AnT) and to determine whether changes in heart rate to workload linearity can be used to accurately estimate anaerobic threshold in runners. Forty-eight male runners competing in different running disciplines performed a graded maximal exercise test on a motor-driven treadmill. The anaerobic threshold was assessed by a nonlinear increase in carbon dioxide output to oxygen consumption ratio (V-slope method). The HR(DP) was determined using the method of deflection of linearity by visual inspection. There was no statistically significant difference between the heart rate at the AnT (176.5 +/- 9.9 bpm) and HR(DP) (177.5 +/- 9.9 bpm, p>0.05), as well as between running speed (v) at the AnT (15.0 +/- 2.2 km/h) and HR(DP) (15.0 +/- 2.0 km/h). We conclude that the intensity at the HR(DP) based on HR response during graded exercise in runners, can be recommended as a valid tool for non-invasive detection of the intensity at the AnT.