Exercise Testing Protocols

[burner]

At present i am trying to do a final year research project in my physiotherpay degree. Part of it includes using an exercise test to establish the relationship between VO2 and Heart Rate on healthy individuals. I did a pilot study using the Bruce Protocol, however even with a fit participant this is a very aggressive protocol. I have looked at the Modified Bruce Protocol and the Balke-Ware Protocol but they seem to take it to the other extreem, starting at a very small level of stress, resulting in the protocol becoming time consuming.

1. Is there a test inbetween these extreems?
2. If not, is it possible to start the protocol half way through / miss out the lower levels, so I am not testing prople at such small levels of stress?
3. Will starting the protocol half way through / missing out the lower levels affect the reliability and validity of the protocol?

Kind Regards

[zk]

What grades and speeds does modified Bruce stress test uses during 5th,6th and 7th stages?Is finishing 5th stage(15min)on regular Bruce stress equal to finishing 7th stage(23min)or more on modified Bruce stress test?Why modified Bruce stress is not used(by most people) for ruling out coronary artery disease instead of agressive regular Bruce stress with 3 minutes stages?

[Mantels]

It is a very difficult test.

[tickertock]

go to http://www.patient.co.uk/showdoc/4000517/  this will give you a pretty good run down as to what is required for the bruce exercise stress test, requirements to achieve what is necessary for the results to be fairly accurate, etc., it doesn't elaborate on the details of the modified bruce version in detail that much though i understand from what I ve read elsewhere that stage 3 of the modified bruce version is equivalent to stage 1 of the standard test, i could be wrong about that though.

[dhflp]

Could you describe modified Bruce version in terms of stages,speeds,grades,times and mets?Do you know of any other mets calculator on net?

[Mantels]

As far as I can tell mine was not modified.

I suspect generally most people are in pretty poor shape to begin with.

Probably why I was able to continue running during my MI and was suprised.

[Mantels]

I have taken the Bruce test 2 times post MI, stenting and 100% blockage LAD.

I had 19 minutes the first time (6 months post)and 20:15 (14 months post) the second time. Both times, I chose to stop because I thought I was going to fall off.The treadmills tend to be a little antiquated and tough to balance when tired.

My Dr. refuses to let me do the test again.

Probably why I had the MI in the first place?

My opinion is that if you don't push hard on these tests how will you know what levels you can push your self on the outside?
If I was going to have another MI I wanted to try my hardest to cause it in the Dr.'s office. Otherwise I would always question what I could do.

[tickertock]

I understand that after a MI , patients are tested on a modified Bruce version which is a lighter test than the original Bruce, my understanding only.

I guess to a certain extent the exercise test is like an Ep study, anyone can be thrown into V-fib with very aggressive stimulation,but in most instances its completely uncalled for and should be avoided.

[zk]

1.Does anyone know how many VO2 or METS was achieved on the above Bruce treadmill protocol stress test? 2. Are you saying VO2 or METS should be estimated from last stage,in this case 5th stage, no matter if above person walked 2 or 3 minutes in stages 1 and 2 on protocol? 3. I think exrx calculator is not as accurate as treadmill METS calculator(taken during test by computer),because it does not take into account weight and height of a person.Physical education trainer told me athletes who finish 5th and start 6th stage on Bruce treadmill protocol stress test usually achieve 18 METS on computer print out.Does anyone know anything about this?

[tickertock]

I really don't know that much about it, but I would go by the actual treadmill test rather than exrx calculator, I think that only gives a general idea rather than an accurate assessment of each individual, for example once you can achieve 85-90% of your maximum predicted heartrate for your age and completes stage 3,then from what I gather it will produce fairly accuarte results abiout 70% of the time.

Like wrote above my test was stopped not because I couldn't continue, but because I had reached 93% of my maximum predicted heartrate, exercised for 10 minutes, achieved 11 mets, according to the results, had a normal B/P response in every stage. Exercise duration 10 minutes. Workload achieved: 11 mets. Target heartrate 155bpm( thats 85% of maximum predicted heartrate) Heartrate response: normal, Heartrate achieved: 171 bpm.  % of maximum predicted heartrate 93% , Resting B/P 138/76 , Peak B/P 188/84 , B/P response : normal , Symptoms: none , Reason for stopping: The patient had achieved or exceeded their target heartrate, The St segment response: No significant St segment shift, ECG interpretation and conclusions: Normal, no clinical or electrocardiographic evidence of myocardial ischemia.

I would go by what the cardiologist performing the test says, of course the longer you go the more fit the calculator will determine you to be. From what I gather 10 minutes or longer on the Bruce and 10 mets and above your're in fair to good shape.

[tickertock]

just vsited the website and calculated my score on the bruce stress test from 4 years ago, it delivered a poor rating despite my cardiologist observing and performing the test and telling me i did excellent, leaves me wondering. I exercise for about 10 minutes and achieved 11 mets. The test was stopped not because of symptoms or fatigue  simply stopped because I had achieved 93% of my maxium predicted heartrate, even though i felt like going longer but was told it was not necessary, I guess I'll take my cardio's word for it, though the test lasted only 10 minutes from what I gathered I was told I was put through a vigorous test for such a short time.Any thoughts??

[Mantels]

http://www.exrx.net/Calculators/Treadmill.html

[tickertock]

i guess the grading has more to do with the amount of time you exercised rather than anything else. I guess the longer you exercise the more fit you are considered to be and does not necessarily relate to the validity of test in diagnosing possible coronary heart disease just my assumption, funny my cardio thought i was reasonably fit also.

[zk]

Bruce protocol treadmill stress test.                                                           Stage 1. Speed(mph) 1.7, Grade 10(%), Time 02:00.                                                          Stage 2. Speed(mph) 2.5, Grade 12(%), Time 04:00.                                                          Stage 3. Speed(mph) 3.4, Grade 14(%), Time 07:00.                                                          Stage 4. Speed(mph) 4.2, Grade 16(%), Time 10:00.                                                          Stage 5. Speed(mph) 5.0, Grade 18(%), Time 12.30.                                                                                                                          1. Does anyone know how many Vo2 or mets was achived on the above Bruce potocol treadmill stress test?                                                           2. If above person went(lasted) for 30 more seconds and had finished stage 5 should his Vo2 or mets be calculated from whatever is for finishing stage 5(eventhough in stage 1 he walked for 2 instead 3 minutes and than also in stage 2 he walked for 2 instead of 3 minutes)?                                                       3. Will starting Bruce protocol treadmill stress test with 2 minutes instead 3 minutes in stages 1 and 2 affect the reliability of protocol? Thank you

[Mantels]

Bruce Treadmill Stage 1 2 3 4 5 6  7
Speed (mph) 1.7 2.5 3.4 4.2 5.0 5.5 6
Grade (%) 10 12 14 16 18 20 22

[axg9504]

Could you describe this protocol in terms of duration/pace required (in minutes per mile)? Thanks.

[calico1]

I think Bruce protocol tries to simulate how your body will react to stimuli that more demanding than normal and would not give you enough time to warm up. These stimuli are very common in our day to day lives (eg. catching a bus, chasing your kids, etc). So I think it's good to use a stringent test. I'm not a doctor, this is just an opinion.

[runnertom]

As a long time runner who has taken a number of Bruce protocol stress tests, I would have to agree that it is far too agressive to accurately assess VO2 max. I have found from general racing experience that a fairly lengthy warmup is essential. Also, I have heard it said that the requirement increases with age. From 30 years running experience, I would tend to agree.

I find in the Bruce test that I go from a fairly comfortable pace where I may be at 145 bpm or so, but the increased output for the next increment puts me immediately into an non-sustainable pace. A minute or so of that and the test is terminated as I my heartrate approaches max. I have considered asking to be given time to go run outside for 10 minutes or so before the test starts, but I realize the purpose of the testing in my case is to assess my heart under stress, not to determine my VO2 max.

Years ago, I had a test on a bicycle ergometer that did not seem to progress so agressively, but leg strength or endurance became the limiting factor in spite of my extensive cycling experience. I don't think the results correlated well with running either. It estimated my VO2 max at 55, but my actual running performance predicted about 65.

[Momto3]

Congrats on nearing the completion of your program of study!!!

I am not a doctor, but I know that I have been through a number of stress tests (another scheduled for November).  Normally, I am assessed using the Bruce protocol, but have also been assessed with the Cornel protocol.  I was told the Bruce was a more stringent test...Based on the exercise portion of the exam, I would agree ; )

Good luck with your research.

[CCF-M.D.-MJM]

Hi Burner,

There are protocols between these extremes but we don't use them.  Almost all of the diagnostic and prognostic databases were collected from the Bruce protocol.  I am sure you can find the others some textbooks; I am just not sure where to tell you to look.

2. if not, is it possible to start the protocol half way through / miss out the lower levels, so I am not testing people at such small levels of stress?

It is possible, but the easier stages only take 6-9 minutes and can serve as a warm up.  The VO2 tests I have seen at the Olympic training camp used the Bruce protocol.  You may want to contact them directly.  Another person you may want to ask is David Costill (PhD) from Ball State.  You probably already know the name, but I bet he would be more helpful than I.

3. Will starting the protocol half way through / missing out the lower levels affect the reliability and validity of the protocol?

You could no longer call it the Bruce protocol if you changed it.  I would use a standardized protocol, otherwise people may use this a grounds to criticize your study or make it more difficult to compare.

Good luck with your project.