My cardiologist uses the Bruce Protocol test, which I think is pretty much standard throughout the US and Europe. Medically, the test is typically limited to 12 minutes (although sports centers testing oxygen levels of well trained atheletes will keep them on the treadmill for typically 21 minutes).
The threadmill speed and inclines are as follows:
Stage 1 (1- 3 minutes) 1.7 mph 10% incline
Stage 2 (4- 6 minutes) 2.5 mph 12% incline
Stage 3 (7-9 minutes) 3.4 mph 14% incline
Stage 4 (10-12 minutes) 4.2 mph 16% incline
There is also a Modified Bruce protocol, which starts at a lower workload than the standard test, and is typically used for elderly or sedentary patients. The fist two stages of the Modified Bruce Test are performed at a 1.7 mph and 0% grade and 1.7 mph and 5% grade, and the third stage corresponds to the first stage of the Standard Bruce Test protocol as listed above.
The Bruce Protocol is described in more detail at
http://www.topendsports.com/testing/tests/bruce.htm
I believe kenkeith was referring to the Balke protocol. Here's a journal article that compares the Bruce vs Balke protocols.
http://www.chestjournal.org/cgi/reprint/68/3/331.pdf
For men the treadmill speed is set at 3.3 mph, with no incline. After 1 minute the elevation is raised to 2%, then 1% each minute thereafter. Walking spped constant.
For women the treadmill speed is set at 3.0 mph, with the gradient starting at 0%, and increased by 2.5% every three minutes. Walking speed constant at 3.0 mph.
The test score is the time taken on the test, in minutes. Ideally this should be between 9-15 minutes. The individual's system is monitored with an EKG and echocardiogram and stopped if EKG indicates an abnormality or if the individual becomes short of breath and/or fatigue.
Another measurement with the treadmill test are METs (metobolic equivalent tasks). Three years ago my stress test was stopped at 7.1 METs due an EKG reading.
What’s a MET? A "metabolic equivalent" (MET) is the amount of oxygen used by an average seated person. METs increase with the intensity of exercise. Curently I can do 7 METs without any problem on the treadmil for 20 minutes (I take a slow acting nitrate prior!).
2 METs - walking at 2 mph
5 METs - walking at 4 mph
8 METs - jogging at 6 mph
The risk of death for those who could not get beyond 4 METs (brisk walking) was more than double the group who could get past 8 MET (jogging).
I just had one done a couple months ago. I was on the treadmill for 10 minutes plus had some down time after walking so they could monitor my recovery time. I don't know how fast or degree of incline because it doesn't have the screen in front like those at the gym. I believe they look for a target heart rate and certain blood pressure. Once you reach that, you're done. The speed was a very slow walk at first then gradually increased but I never had to run. The incline was bumped up every minute or so (that's my guess). It will vary from person to person depending on how your heart responds to the exercise. That's the point of the test. Some folks only last for a few minutes and then come off.