This document explores how altitude affects the relationship between internal load measures—RPE-Leg and RPE-Breathe—and various training and recovery markers including muscle soreness, external load (PlayerLoad), and session duration in athletes. Through a series of data-driven graphs and interpretations, the analysis highlights the amplified internal strain athletes experience in hypoxic environments, emphasizing the mismatch between perceived effort and external workload. Practical recommendations are provided for coaches and practitioners to optimize training prescription, monitor adaptation, and reduce overtraining risk during altitude exposure. The document integrates recent literature to support the findings and reinforce best practices in load management at altitude.