Which statement about aerobic training is true?

• A. It increases resting heart rate
• B. It decreases resting heart rate
• C. It has no effect on oxygen transport
• D. It reduces fat metabolism

Answer: (B)

Regular aerobic training makes the heart more efficient. The heart pumps more blood per beat (increased stroke volume) and, with better blood flow to muscles through more capillaries, it can meet the body's needs with fewer beats at rest. Because of this improved efficiency, resting heart rate tends to decrease. This drop is a common and reliable sign of cardiovascular adaptation to endurance training.

The statement about oxygen transport is not correct in saying there’s no effect—endurance training enhances oxygen delivery and utilization through a stronger pump and better tissue oxygen extraction. The idea that fat metabolism is reduced isn’t accurate either; aerobic training usually increases fat oxidation during submaximal exercise and improves overall metabolic flexibility.