Why is it important for heart rate to increase during exercise? Answer in 3-5 sentences.

During exercise, the heart rate increases to meet the increased oxygen and nutrient demands of the muscles. This allows our bodies to deliver more oxygen and nutrients to the muscles and remove waste products more efficiently. Increased heart rate also helps to strengthen the heart muscle and improve its overall efficiency. Additionally, a higher heart rate during exercise helps to increase cardiovascular endurance and improve fitness levels.