This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'All of the following are increased in isometric exercise, EXCEPT: \nSelect and explain. \nA. Hea rate, B. Cardiac output, C. Mean aerial pressure, D. Systemic vascular resistance', 'role': 'user'}, {'content': "Answer: D \nExplanation: As a result of vasodilation in the vascular bed in the active muscles, the peripheral resistance to blood flow is reduced during exercise, but the elevation in cardiac output causes the blood pressure to rise. The increase in cardiac output results principally from an increase in hea rate. When the cardiac output increases, mean aerial pressure also increases. Some increase in stroke volume also takes place. Ref: Abdulla C., Nixon J.I. (2009). Chapter 34. The Athlete's Hea. In M.H. Crawford (Ed), CURRENT Diagnosis & Treatment: Cardiology, 3e.", 'role': 'assistant'}]