How does training typically affect maximal cardiac output and stroke volume?

How does training typically affect maximal cardiac output and stroke volume?

• A. Maximal cardiac output decreases; stroke volume decreases.
• B. Maximal cardiac output remains constant and stroke volume unchanged.
• C. Maximal cardiac output is maintained or increased; stroke volume increases.
• D. Maximal cardiac output increases but stroke volume falls.

Answer: (C)

Training mainly boosts the heart’s ability to pump more blood per beat. Endurance adaptations enlarge the left ventricle and improve filling, so stroke volume at maximal effort increases. At the same time, maximal heart rate tends to stay the same or fall a little in trained individuals, so the overall maximal cardiac output (which is heart rate × stroke volume) is kept or can be higher because the bigger stroke volume compensates for any modest change in heart rate. So, the best description is that maximal cardiac output is maintained or increased, and stroke volume increases.

Training mainly boosts the heart’s ability to pump more blood per beat. Endurance adaptations enlarge the left ventricle and improve filling, so stroke volume at maximal effort increases. At the same time, maximal heart rate tends to stay the same or fall a little in trained individuals, so the overall maximal cardiac output (which is heart rate × stroke volume) is kept or can be higher because the bigger stroke volume compensates for any modest change in heart rate. So, the best description is that maximal cardiac output is maintained or increased, and stroke volume increases.