Abstract: This paper reviews the current research on the protective effects of active heat acclimatization against heat stress-induced declines in athletic performance and increased injury risk. It finds that these effects are primarily mediated through enhanced heat dissipation, improved cardiovascular homeostasis, regulation of autonomic nervous system activity, and the induction of heat shock protein expression. However, the impact of different intervention modalities, durations, and individual training levels on outcomes remains inconsistent, and there is a lack of standardized assessment criteria. Future research should further integrate evidence from physiological, neurocognitive, and molecular levels to establish a generalizable framework for optimizing active heat acclimatization.