I don't know. There were no displays on the treadmill when I did my stress test. They mostly judged my "success" on my heart rate and blood pressure readings compared to how long I lasted. I never had to run; it was just a walking speed with some incline increases. I did about 10 minutes I guess and then had to lie down for the recovery part. I think I did just fine.
Most are done as outlined below:
Bruce Protocol
Stage Min % grade MPH METS
1 3 10 1.7 4.7
2 6 12 2.5 7.0
3 9 14 3.4 10.1
4 12 16 4.2 12.9
5 15 18 5.0 15.0
Jon