The body adapts to endurance training over time by increasing the efficiency of its cardiovascular and muscular systems. This leads to improved oxygen delivery and utilization, enhancing overall stamina and performance. Moreover, adaptations include greater mitochondrial density, improved capillary networks, and increased muscle glycogen storage. These changes allow the body to sustain prolonged physical activity more effectively. As proficiency develops, athletes may experience reduced perceived exertion during activities, resulting in better performance outcomes and improved fitness levels.