Regular endurance training typically leads to an increase in heart size, particularly the left ventricle, allowing for more efficient blood flow and improved oxygen delivery during physical activity. With consistent training, the heart's muscle function strengthens, leading to a lower resting heart rate and enhanced cardiovascular efficiency. This adaptation not only boosts performance but also reduces the risk of heart disease and improves overall health. Additionally, endurance training can enhance the heart's ability to respond to stress, further benefiting fitness and health in the long run.