Which factor explains why mean arterial pressure tends to rise only modestly during moderate aerobic exercise?

Which factor explains why mean arterial pressure tends to rise only modestly during moderate aerobic exercise?

• A. Cardiac output increases while systemic vascular resistance falls due to vasodilation in active muscles
• B. Cardiac output decreases and SVR increases
• C. Both CO and SVR increase proportionally to raise MAP dramatically
• D. There is no change in any parameter

Answer: (A)

During moderate aerobic exercise, the body increases cardiac output to deliver more oxygen to working muscles, driven by a higher heart rate and stronger contractions. At the same time, the blood vessels supplying those muscles dilate a lot due to local metabolic signals, which lowers systemic vascular resistance. Because mean arterial pressure is influenced by both how much blood is being pumped (cardiac output) and how much resistance the blood faces (systemic vascular resistance), the rise in CO is offset by the drop in SVR. The net effect is only a modest increase in MAP. In short, CO goes up while SVR falls due to vasodilation in active muscles, keeping MAP changes relatively small during moderate exercise.

During moderate aerobic exercise, the body increases cardiac output to deliver more oxygen to working muscles, driven by a higher heart rate and stronger contractions. At the same time, the blood vessels supplying those muscles dilate a lot due to local metabolic signals, which lowers systemic vascular resistance. Because mean arterial pressure is influenced by both how much blood is being pumped (cardiac output) and how much resistance the blood faces (systemic vascular resistance), the rise in CO is offset by the drop in SVR. The net effect is only a modest increase in MAP. In short, CO goes up while SVR falls due to vasodilation in active muscles, keeping MAP changes relatively small during moderate exercise.