Sex-Based Differences at Ventilatory Thresholds in Trained Runners

Objective: This study aimed to compare trained male and female athletes regarding physiological, perceptual, and performance variables at ventilatory thresholds (VT1 and VT2). Methods: Twenty-four male and nineteen female trained runners (age: 27.9 ± 6.4 vs. 24.4 ± 4.4 years; body mass: 61.8 ± 4.3 vs. 52.6 ± 4.1 kg; height: 174.6 ± 5.8 vs. 165.0 ± 5.0 cm for males and females, respectively) performed a graded exercise test to exhaustion on a treadmill. During the test, oxygen consumption, respiratory exchange ratio, running power output, heart rate, muscle oxygenation, and rate of perceived exertion were analyzed. Sex differences were evaluated with an unpaired-samples t-test. Results: Males exhibited significantly higher respiratory exchange ratios (0.87 ± 0.04 vs. 0.83 ± 0.03; 1.03 ± 0.06 vs. 1.01 ± 0.06) and absolute running speeds (15.00 ± 1.06 vs. 12.42 ± 1.22 km·h−1; 19.04 ± 1.06 vs. 16.32 ± 1.29 km·h−1) at both thresholds (p < 0.05), whereas women showed higher muscle oxygenation in vastus lateralis (60.44 ± 21.21 vs. 26.38 ± 10.21%) and fractional utilization of maximal aerobic speed (93.64 ± 6.44 vs. 91.43 ± 3.21%) at VT2 (p < 0.01). Also, rate of perceived exertion was similar between sexes at both thresholds. Conclusion: Males showed higher absolute physiological values, while females demonstrated greater fractional utilization at VT2 and higher muscle oxygenation. No sex differences were observed in rate of perceived exertion. These findings highlight the importance of using ventilatory thresholds in training prescription.