<prompt> Cardiac output increase in exercise byIncrease in heart rateIncrease in preloadIncrease in afterloadSympathetic stimulation  <response>: Ans: a Increase in HR Ref: Ganong 22nd ed p.632, 633In muscular exercise there is increase in sympathetic activity resulting in increased cardiac contractility and heart rate. Rise in heart rate is the major event that occur in normal individuals compared to increase in contractility, remember Cardiac output HR X Stroke volumeTherefore, cardiac output increases in normal individuals at the cost of increase in heart rate. 