Final answer:
In stages 2 and beyond, the heart rate used to determine workload is between 120 and 160 bpm. As heart rate increases during exercise, stroke volume initially remains high but gradually decreases. It's important to monitor heart rate to maintain a healthy cardiovascular response.
Step-by-step explanation:
In stages 2 and beyond, the heart rate used to determine workload is between 120 and 160 beats per minute (bpm).
During exercise, as the heart rate increases, the stroke volume (SV) initially remains high. However, as the heart rate continues to rise, the SV gradually decreases due to decreased filling time. Eventually, the cardiac output (CO) will decrease as the SV falls faster than the heart rate increases. Therefore, it is important to monitor heart rate to ensure it stays within the target range of 120-160 bpm to maintain a healthy cardiovascular response.
For example, if an individual's heart rate during strenuous exercise is 150 bpm, the time per beat in seconds would be calculated as:
- Divide 60 seconds (1 minute) by 150 bpm to get the time per beat: 0.4 seconds