Background <p>The Elevation Training Mask (ETM) has gained popularity as a wearable training device that increases respiratory workload by raising inspiratory and expiratory resistance during exercise. However, evidence regarding the acute effects of ETM use on anaerobic performance and post-exercise physiological responses is limited. Therefore, this study aimed to investigate the acute effects of ETM use on anaerobic performance and post-exercise heart rate and blood lactate responses in young male athletes.</p> Methods <p>Fifteen trained young male athletes (age = 20.40 ± 1.68 years) participated in a randomized, counterbalanced, crossover design involving three experimental conditions: no-mask, ETM set at the manufacturer-defined 9,000 ft resistance setting, and ETM set at the manufacturer-defined 12,000 ft resistance setting. Peak power, average power, repeated-sprint power, fatigue index, heart rate (HR), rating of perceived exertion level (RPE), and blood lactate levels were evaluated.</p> Results <p>In the 9,000 ft ETM and 12,000 ft ETM trials, peak power, average power, and repeated-sprint power values were found to be statistically significantly lower compared to the no-mask condition (<i>p</i> &lt; 0.05). Furthermore, RPE values were statistically significantly higher, and blood lactate levels were statistically significantly lower in both ETM conditions (<i>p</i> &lt; 0.05).</p> Conclusions <p>These findings demonstrated that the use of ETM during high-intensity exercise in young male athletes may result in lower peak, mean, and repeated-sprint power, higher rating of perceived exertion, and lower blood lactate levels. Therefore, the potential effects of ETM use on performance in sports activities where anaerobic performance is important should be considered, and the purpose of use should be carefully evaluated in line with performance requirements.</p>