Changes in the cardiovascular system occur rapidly during physical exertion to meet metabolic demands. The graphs in the figure show the changes in stroke volume and heart rate of an Alaskan sled dog running at various steady-state speeds on a treadmill.
Use the data in the figure to calculate the cardiac output of the sled dog at a running speed of 20 km h−120\text{ km h}^{-1}20 km h−1. Include appropriate units with your answer.
Suggest an advantage to the sled dog of this increased cardiac output during high-speed running.
