During endurance training, which change occurs in the heart?

During endurance training, which change occurs in the heart?

• A. Heart rate increases during exercise
• B. Lungs increase capacity
• C. Heart muscle increases in size, thickness, and strength
• D. Blood pressure decreases

Answer: (C)

Endurance training makes the heart muscle grow thicker and stronger, increasing its size and its ability to contract forcefully. With regular aerobic work, the heart handles more blood returning to it and must pump more efficiently, so the left ventricle undergoes hypertrophy—its walls thicken and the chamber can enlarge a bit. This strengthening leads to a higher stroke volume, meaning more blood is pumped with each beat, and overall greater cardiac output during activity. As a result, the heart becomes more efficient, often allowing a lower resting heart rate for a given level of fitness.

Endurance training makes the heart muscle grow thicker and stronger, increasing its size and its ability to contract forcefully. With regular aerobic work, the heart handles more blood returning to it and must pump more efficiently, so the left ventricle undergoes hypertrophy—its walls thicken and the chamber can enlarge a bit. This strengthening leads to a higher stroke volume, meaning more blood is pumped with each beat, and overall greater cardiac output during activity. As a result, the heart becomes more efficient, often allowing a lower resting heart rate for a given level of fitness.