BACKGROUND: Endurance exercise intensities can be categorized into moderate, heavy, and severe domains based on physiological responses during incremental exercise testing. Since the evaluation of metabolic thresholds is not always possible, this study assessed the accuracy of fixed intensity anchors to estimate lactate thresholds. METHODS: 165 (64 females, 101 males) recreational runners performed a maximal incremental treadmill test. The first (LT1) and second (LT2) lactate thresholds were determined as percentages of maximum heart rate (HR), oxygen consumption (VO RESULTS: Females had a higher relative HR, VO CONCLUSION: LT1 occurred at higher relative intensity in females, suggesting a need for sex-specific intensity anchors. The speed-derived estimates were the most accurate, but the estimation of maximum values impaired the prediction accuracy. Thus, the optimal method also depends on the availability of the maximum values.