Many studies have used the heart rate deflection points (HRDP) during incremental exercise tests, because of their strong correlation with the anaerobic threshold (AT). The aim of this study was to evaluate the profile of the heart rate deflection points identified by a computerized method and compare it to ventilatory and lactate thresholds. Twenty-four professional soccer players (age, 22 ± 5 yr; body mass, 74 ± 7 kg; height 177 ± 7 cm) volunteered for the study. Subjects completed a Bruce-protocol incremental treadmill exercise test to volitional fatigue. Heart rate (HR) and respired gases were recorded continuously at ≥ 1 Hz during exercise testing. Subsequently, the time course of the HR was fit by a computer algorithm and a set of lines yielding the lowest pooled residual sum of squares was chosen as the best fit. This procedure defined two heart rate deflection points (HRDP1 and 2). The HR break points averaged 43.9 ± 5.9 % and 89.7 ± 7.5 % of &OV0622;O2 peak. HRDP1 showed poor correlation with VT (r =.50), but HRDP2 was highly correlated with the respiratory compensation point (RC) (r = .98). Neither HRDP1 nor HRDP2 was correlated with LT1 (at &OV0622;O2= 2.26 ± 0.72 L/min;r = .26) or LT2 (2.79 ± 0.59 L/min;r = .49) respectively. LT1 and LT2 also were not well correlated with VT (2.93 ± 0.68 L/min r = .20) or RC (3.82 ± 0.60 L/min r = .58), respectively. Although the HR deflection points were not correlated with LT, HRDP2 could be identified in every subject and was strongly correlated with RC, consistent with a relationship to cardiorespiratory fatigue and endurance performance.