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Home / The Optimal Duration to Reach Using a Continuous Protocol Gxt Should Be to Minutes

The Optimal Duration to Reach Using a Continuous Protocol Gxt Should Be to Minutes

Bruce Protocol Stress Test

The Bruce Test is commonly used treadmill exercise stress test. It was developed as a clinical test to evaluate patients with suspected coronary heart disease, though it can also be used to estimate cardiovascular fitness. See also a general description of Exercise Stress Tests. As this stress test is a maximal test performed commonly on people with heart problems, the test should be performed under the supervision of appropriately trained medical staff.

purpose: to evaluate cardiac function and fitness.

equipment required: treadmill, stopwatch, a 12-lead electrocardiograph (ECG) machine and leads, sticking tape, clips.

pre-test: Explain the test procedures to the subject. Perform screening of health risks and obtain informed consent. Prepare forms and record basic information such as age, height, body weight, gender, test conditions. Perform an appropriate warm-up. Attach ECG leads if required. See more details of pre-test procedures.

procedure: Exercise is performed on a treadmill. If required, the leads of the ECG are placed on the chest wall. The treadmill is started at 2.74 km/hr (1.7 mph) and at a gradient (or incline) of 10%. At three minute intervals the incline of the treadmill increases by 2%, and the speed increases as shown in the table below. (see Bruce Test video examples). The test should be stopped when the subject cannot continue due to fatigue or pain, or due to many other medical indications.

Stage Speed (km/hr) Speed (mph) Gradient
1 2.74 1.7 10
2 4.02 2.5 12
3 5.47 3.4 14
4 6.76 4.2 16
5 8.05 5.0 18
6 8.85 5.5 20
7 9.65 6.0 22
8 10.46 6.5 24
9 11.26 7.0 26
10 12.07 7.5 28

modifications: There is a commonly used 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.

exercise stress testexercise stress testing

results: The test score is the time taken on the test, in minutes. This can also be converted to an estimated VO2max score using the calculator below and the following formulas, where the value "T" is the total time completed (expressed in minutes and fractions of a minute e.g. 9 minutes 15 seconds = 9.25 minutes). As with many exercise test equations, there have been many regression equations developed that may give varying results. If possible, use the one derived from a similar population and which best suits your needs.

VO2max (ml/kg/min) = 14.76 - (1.379 × T) + (0.451 × T²) - (0.012 × T³) (this formula is the one used for the calculator below)

Women: VO2max (ml/kg/min) = 2.94 x T + 3.74
Women: VO2max (ml/kg/min) = 4.38 × T - 3.9

Men: VO2max (ml/kg/min) = 2.94 x T + 7.65
Young Men: VO2max (ml/kg/min) = 3.62 x T + 3.91

VO 2max calculator: Enter your total time on the Bruce Test in the box below and click calculate. The time in minutes should be expressed in minutes and fractions of a minute e.g. 9 minutes 15 seconds = 9.25 minutes.

target population: Patients with suspected coronary heart disease, and athletes in sports in which aerobic endurance is a important component, such as distance runners.

advantages: You can also get measurement of maximum heart rate by recording heart rate during the test, which can be used in training programs to set intensity.

disadvantages: Relatively large time and costs required. Specialist training is required to interpret exercise ECG traces.

other comments: The original Bruce protocol was developed in 1963 by Dr. Robert. A. Bruce. Other similar exercise stress test protocols include Astrand, Naughton and Balke.

caution: This test is a maximal test, which requires a reasonable level of fitness. If used recreational athletes or people with health problems, injuries or low fitness levels, please have medical assistance on hand.

Similar Fitness Tests

  • See also the similar Balke Test.
  • Astrand Treadmill Test
  • Treadmill VO2max

Related Pages

  • Stress Tests — a general description of exercise stress tests.
  • See Stress Test Videos.
  • Profile of Robert Bruce — fitness testing pioneer and Bruce Test developer.
  • Calculating Treadmill Gradient
  • VO2max test and other tests of aerobic capacity.
  • See heart rate measurement methods if heart rate measurement is also required
  • Ratings of Perceived Exertion Scale if you want to quantify effort.
  • Other fitness tests conducted on treadmills
  • Health Tests for Athletes

Old Comments

Commenting is closed on this page, though you can read some previous comments below which may answer some of your questions.

  • On the contrary (2016)
    The Bruce Protocol is a very poor alternative to the Balke protocol for anyone who isn't young and athletic, AND a runner who trains on steep hills - which means that it is particularly poorly suited for the purpose it is most used for: to assess cardiovascular fitness in older people who may have heart disease.

    The Bruce protocol's stages are both too long (3 minutes) and way too discontinuous to provide an accurate graded measure of aerobic fitness for the general population. It also doesn't provide adequate time to warm up, which can be dangerous for older people who may have heart conditions.

    Stage 4, which begins to test the upper level of fitness, requires a speed of 4.2mph up a 16% grade. This is a 14.6 MET level exercise that requires a VO2 Max of over 51, which would put a man aged 36-45 in the top 5-10% for his age category, while Stages 5 (5mph at 18% grade) and 6 (5.5mph at 20%) require that one be able to jog, which many older people aren't trained for and may not be able to do anyway due to foot, knee, hip, or back problems. How many of the people reading this have ever tried to walk at 5mph even on the flat?

    Even extremely fit and fast bicyclists, rowers, or runners who don't train on steep hills, or who aren't super lean like elite distance runners, are going to be at a grave disadvantage at even the Bruce's beginning grade of 10%, never mind 16-20% yet these people may be more aerobically fit than the super lean runners who train regularly on steep hills.

    The Balke protocol is much better as it is conducted throughout at a fixed speed that is a normal walking pace: 3.3mph for men, and 3mph for women. The grade begins at 0 and is bumped 1% for each minute (except for the first bump, which is 2%). The Balke thus accommodates even people with severe limitations and handicaps, yet provides an accurate graded assessment of their capabilities without washing them out at the first or second stage bump. On the other end of the scale, the Cooper Aerobics Clinic, which has been using the Balke Protocol on many tens of thousands of patients for over 40 years now, and with few adverse results, has a desirable modification to the Balke that tops the grade out at 25% after 25 minutes, and adds .2mph to the speed for each minute thereafter. This makes it possible for superfit people who can keep going that long to add a few minutes before having to switch to jogging that they may not be trained for.

    The Balke requires only that the subject be able to sustain a normal walking pace, thus it requires no special athleticism or trained hill climbing muscles, and it provides a wide linear measure of aerobic fitness that runs the full gamut of human performance.

  • Siegfried Verheijke On the contrary (2017)
    I have done the Bruce test (T = 15:16, METS = 20.4) and I am inclined to agree with you. I think that the 3' intervals are too long and the difference in difficulty between the stages is too great. At that time I was 11 kg heavier than now and not nearly as fit, but thanks to my vegan lifestyle I have improved a lot.. I am an amateur athlete, and while being overweight at the time, I do have a lot of experience running up hills. So it definitely is an advantage for people who are used to this. Another issue is that it doesn't really measure your maximum HR. Mine maxed out at 166 (I am 52), but about 10 days later I managed to get to 174 bpm at the end of a 50' run in the mountains. Tests like that should last longer, as it takes my heart longer to reach its max HR, I think. I plan to simulate the test again on a treadmill later this week. I hope to reach 18:00! And will look at the Balke method, as it looks to be more refined. Happy training, On The Contrary!
  • Ralph (2014)
    There's no mention of when the test should end, and so no way to score. The table only says what to do at 2min intervals, not when the test should be stopped.
  • Rob Admin Ralph (2014)
    I have added some information about when the test should be stopped. There are many reasons to stop a stress test, which is best determined by the medical personnel conducting the test.
  • Layla Ralph (2014)
    The test should be stopped when the individual reaches 80% of their maximum heart rate.
  • Rick O'Dell Layla (2014)
    Disagree, especially when the subject doesn't have a "measured" maximum heart rate (HR). I'm 74 and am a heart patient. A supervised stress test should last as long as the patient's mind and body can take it. It's the safest way to determine your maximal heart rate (HR), which is the basis for all creditable training programs. My Dayton, OH cardiologist advocated maximum cardiovascular effort. If the 80% max HR is used without actually having a measured max HR, the 220 - age rule will be used. This does NOT work for many people I know. For example, since I am 74, my estimated max HR is 146; 80% of 146 is 117. Since my resting HR is 49, 117 is at the lower end of my aerobic range (112-144). My measured max HR is actually 175 (and I take a beta-blocker daily). I've used wireless HR monitors for 20 years and strongly advise them for type"A" people like myself. Yesterday, at the end of an indoor Concept2 interval rowing session my HR peaked at 170. I always insist that stress test monitors allow me to determine when to press the "off" button. If they resist I raise hell with the cardiologist. BTW: Last year my regular Bruce Protocol test lasted 14:08. Two years before I made 15:00. I am now leg limited (not heart/lung limited) because I can no longer run and cannot walk long distances because of lumbar problems. Conversion of Bruce Protocol treadmill times to VO2MAX is readily available on the Internet, as are age/gender standards.
  • Matsobane Rick O'Dell (2016)
    I agree with the fact that a test should me stopped when the patient reaches maximum heart rate. I understand your case as to why you disagree with this fact, is because you have been physically active for quiet a long time now, you probably have accumulated a lots of benefit of exercise, specifically improved cardiorespiratory endurance, which is the one that makes it easy for you to feel like you are not tired even when you have reached max vo2 however to some people who are physically inactive , we are being advised to top the test if they reach vo2 max, because if we don't their body will develop some complications, they might even die on the sport.
  • Justin Rick O'Dell (2015)
    Rick- you are awesome, and you are right on regarding max heart rate!
  • Julien Rick O'Dell (2014)
    Rick, you are a 74 year old machine! way to go!!
  • Imran Ahmed Rick O'Dell (2015)
    I am 60. My max HR was predicted 160 but on the treadmill I was comfortable at 171 and could have continued exercise which was stopped by medic because her protocol endpoints were reached.
  • Agra1212 Layla (2017)
    actually 85%--that is the sweet spot
  • Cherina Layla (2015)
    Tests that end at 80% of their max heart rate are sub maximal tests. The Bruce protocol is a maximal test which clients perform until volitional fatigue. You would not stop this test if client got to 80% of their max effort.
  • Andrew Layla (2014)
    Completely incorrect. There is no "end-point". There is no "score" either. The test is used to determine the presence of cardiac ischaemia in patients who experience exertional chest pain.

    The ECG is to look for ST segment changes such as depression or elevation.

    The stages are specifically designed with a clinical setting in mind. Stage 1 is extremely slow and is designed for older patients who can't walk quickly or haven't walked on a treadmill before. The subsequent stages are then made with the intention of increasing the patient's heart rate quickly so they are not walking for longer than 6-12 minutes usually.

    The test can only be described as diagnostic if 85% of the patient's heart rate is acheieved and maintained for longer than a minute, however most physiologists (such as myself) will attempt to acheive 100% of the THR and maintain it for a minute in order for the patient to have completed a conclusive test (as conclusive as a normal treadmill can be, but that's another debate).

    There are numerous other end points, such as a systolic BP over 230mmHg or diastolic BP over 100mmHg, the presence of a serious/life-threatening arrhythmia, such as VT, AF, VF, an SVT or even left bundle branch block. It may also be stopped if 2mm of ST depression or elevation is noted while the patient is symptomatic OR 3mm of ST depression/elevation with no symptoms reported by the patient.

    The test may also be stopped at any stage at the patient's request or if the ECG becomes unclear and is therefore at the physiologist's discretion.

  • Imran Ahmed Andrew (2015)
    You are right, but more precise physical fitness assessment can only be done by a maximal test. Physical fitness as an independent predictor of mortality is worth measuring. People's biological ages vary at the same chronological age therefore age tables to predict maximal heart rate are not reliable.
  • Shreya (2017)
    can the test be stopped wen the target hr is achieved
  • Dissertation help (2016)
    A test like this can also be done to the students who might have that certain kind of disease. From this, they can change their health habits to promote a healthy style of living.
  • Mitwit (2015)
    Getting ready for another treadmill test. As a cardio patient my biggest problem during testing has been my legs hurting. I'm not used to a treadmill much less 10+ % inclines. I have switched my exercise routine from an elliptical to a treadmill just to get my legs in shape for the test. I will look to see if my time increases from 5 years ago...but is practice cheating the test?
  • Arnaldo Santana (2015)
    What would be the purpose of the sticking tape and the clips? I do not understand.
    Also, if I don't have an electrocardiogram machine available, is it okay if I just use my Polar heart rate monitor?
  • Angelbaby (2015)
    Ok I had this test done yesterday and when explaining the test he said I would go to level 4 and once I reached my heart rate I would continue for another minute but I only got to level 3 and he only made me continue for 30 seconds. Why didn't he have me go to level 4 I thought I was doing fine
  • Mitwit angelbaby (2015)
    Hope you found out. My first ended with the tech saying it looked good. That night I got a call TELLING me to be in the docs office first thing in the morning. I bumped a number of scheduled angioplasty patients a few days later. I later found I had a 99% blockage and the OR techs always ask "so when did you have your heart attack?"...never. Still going after 18 years
  • Cecily Bailey mitwit (2016)
    I had the test recently and complete to my max heart rate, but hone i finished the Dr. nearly had a fit because my BP was really high...but he also never give me 60 seconds to remeasure my Bp nor did he ask my current conditioning...Does this seem right?
  • Marc (2016)
    About a year ago I had an eco stress test. I am 53 years old. I lasted about 14 minutes. The eco showed a "mildly" enlarged aorta. 4.3 cm. My doctor said it could have been there for a while or something that is recent. The only way to tell is do another test in a year which I am coming up on? I workout 5 days a week and am in excellent health. A previous heart scan showed no CHD present in my heart. Recently I noticed the my eyes are puffy all of the time. Additionally I have been going to the bathroom more often, especially at night (2-3 times a night). My psa and prostate are normal. I've read that the puffy eyes and frequent urinating could be signs of trouble. Any ideas? Thanks.
  • Rick Marc (2017)
    I took this test when I was in my 20's and was having PVCs. I have always had what some call a functionally small heart, ie faster than normal heart beat. My max heart rate for the test should have been about 180. when I hit 195 the MD kept asking my " how are you, how do you feel ?". I said, "no problem". when my heart rate hit 200 a nurse was standing beside me with paddles in hand and the MD eyes were big and wide. At 210 he shouted, "stop the test" to the tech. Before she could punch the button I was at 220. Panic in the room. slowly my rate dropped. at about 180 the MD asked, "how do you feel"? I said, "Great, let's do it again". He said, "no way". that was 40 years ago.
  • Wj Rick (2020)
    obviously an overreaction by the staff. if your age is 20 hitting 220 on the treadmill is not that big of a deal. proofs in the living 40 years later.
    - WJ , Cardiologist

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