The body adapts to endurance training by undergoing various physiological changes that improve aerobic capacity and efficiency. With regular training, the heart becomes stronger, pumping more blood with each beat, which enhances oxygen delivery to muscles. Muscle fibers may also adapt by increasing the number of mitochondria, improving energy production. Additionally, the body’s ability to utilize fat as a fuel source increases, sparing glycogen for more demanding activities. These adaptations lead to improved stamina, a lower heart rate at rest, and better overall performance in endurance activities.