Final answer:
During an exercise stress test, an adequate stress workload is defined as working at a percentage of the age-predicted maximal heart rate. The correct percentage is 80-90% (option B).
Step-by-step explanation:
During an exercise stress test, an adequate stress workload is defined as working at a percentage of the age-predicted maximal heart rate. The correct percentage is 80-90% (option B).
For example, if a 40-year-old individual has a maximal heart rate of 180 bpm, an adequate stress workload would be reached by exercising at a heart rate between 144 bpm (80% of 180) and 162 bpm (90% of 180).
It's important to note that the percentage may vary based on individual factors and recommendations from healthcare professionals should be followed.