Final answer:
To determine if the steady state HR has been reached, we look at the relationship between HR, SV, and CO. Initially, as HR increases, CO rises. But when HR reaches a point where SV starts to decrease and CO decreases, the steady state HR has been reached.
Step-by-step explanation:
In order to determine if the steady state HR has been reached, we look at the relationship between heart rate (HR), stroke volume (SV), and cardiac output (CO). Initially, as HR increases from resting to approximately 120 bpm, CO will rise. As HR increases from 120 to 160 bpm, CO remains stable, since the increase in rate is offset by decreasing ventricular filling time and, consequently, SV. However, as HR continues to rise above 160 bpm, CO actually decreases as SV falls faster than HR increases. Therefore, when the HR reaches a point where the SV starts to decrease and CO decreases, the steady state HR has been reached.