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{{Short description|Test of physical fitness and cardiac health}}

{{Infobox diagnostic
{{Infobox diagnostic
| name = Bruce protocol
| name = Bruce protocol
| image = RIAN_archive_555848_Testing_on_treadmill.jpg
| image =
| alt =
| alt =
| caption =
| caption = Treadmill for functional diagnostics for competitive athletes (1980)
| pronounce =
| pronounce =
| purpose =evaluate cardiac function
| purpose = evaluate cardiac function
| test of =
| test of = [[Cardiac stress test]]
| based on =
| based on =
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The '''Bruce protocol''' is a [[Cardiology diagnostic tests and procedures|diagnostic test]] used in the evaluation of [[heart|cardiac]] function, developed by [[Robert A. Bruce]].
The '''Bruce protocol''' is a standardized [[Cardiology diagnostic tests and procedures|diagnostic test]] used in the evaluation of [[heart|cardiac]] function and [[physical fitness]], developed by American cardiologist [[Robert A. Bruce]].<ref name="Kennedy2005">{{cite journal |vauthors=Kennedy JW, Cobb LA, Samson WE |title=Robert Arthur Bruce, MD: 1916–2004 |journal=Circulation |date=10 May 2005 |volume=111 |issue=18 |pages=2410–2411 |doi=10.1161/01.CIR.0000164274.41137.75 |pmid=16389672 |doi-access=free }}</ref>


According to the original Bruce protocol the patient walks on an uphill treadmill in a graded exercise test with electrodes on the chest to monitor. Every 3 min the speed & incline of the treadmill are increased.<ref>{{cite journal |last1=Bruce |first1=RA |title=Exercise testing of patients with coronary heart disease. Principles and normal standards for evaluation |journal=Annals of Clinical Research |date=December 1971 |volume=3 |issue=6 |pages=323–32 |pmid=5156892 }}</ref> There are 7 such stages and only very fit athletes can complete all 7 stages. The modified Bruce Protocol is an alteration in the protocol so that the treadmill is initially horizontal rather than uphill, with the 1st few intervals increasing the treadmill slope only.<ref>{{cite journal |last1=Sheffield |first1=L.Thomas |last2=Roitman |first2=David |title=Stress testing methodology |journal=Progress in Cardiovascular Diseases |date=July 1976 |volume=19 |issue=1 |pages=33–49 |doi=10.1016/0033-0620(76)90007-4 |pmid=785541 }}</ref>


The Bruce treadmill test estimates [[VO2 max|maximum oxygen uptake]] using a formula and the performance of the subject on a treadmill as the workload is increased. The test is easy to perform in a medical office setting, does not require extensive training or expensive equipment, and it has been validated as a strong predictor of clinical outcomes.<ref>{{cite journal |last1=Kelly |first1=Jacob P. |last2=Andonian |first2=Brian J. |last3=Patel |first3=Mahesh J. |last4=Huang |first4=Zhen |last5=Shaw |first5=Linda K. |last6=McGarrah |first6=Robert W. |last7=Borges-Neto |first7=Salvador |last8=Velazquez |first8=Eric J. |last9=Kraus |first9=William E. |title=Trends in Cardiorespiratory Fitness: The Evolution of Exercise Treadmill Testing at a Single Academic Medical Center from 1970 to 2012 |journal=American Heart Journal |date=April 2019 |volume=210 |pages=88–97 |doi=10.1016/j.ahj.2019.01.001 |pmid=30743212 |pmc=6441626 }}</ref>
==Definition==

It is a standardized multistage treadmill test for assessing cardiovascular health. Developed by Robert A. Bruce in 1963 who was an American Cardiologist. According to the original Bruce protocol the patient walks on an uphill treadmill in a graded exercise test with electrodes on the chest to monitor. Every 3 min the speed & incline of the treadmill are increased. There are 7 such stages and only very fit athletes can complete all 7 stages.
The modified Bruce Protocol is an alteration in the protocol so that the treadmill is initially horizontal rather than uphill, with the 1st few intervals increasing the treadmill slope only.

==Indication==

Coronary heart disease
Physical fitness

==Purpose==

To evaluate cardiac function and fitness
==Equipment required==
* Treadmill
* Stopwatch
* A 12 lead ECG machine & leads
* Sticking tape
* Clips

==Pre test==

Explain the test procedure to subject
Screening & health risk is to be assessed
A inform consent is taken from patient.
Prepare forms & record basic information such as age,height,body weight,gender,test condition.
Perform warm up exercise


==Procedure==
==Procedure==
Exercise is performed on a treadmill. The leads of the ECG are placed on the chest wall. The treadmill is started at 2.74&nbsp;km/h (1.7mph) & at an inclined gradient of 10%. After 3 min incline of the treadmill is increased by 2%, and the speed increases. Indications to terminate the test include signs or symptoms of [[Coronary ischemia|impaired blood flow to the heart]], [[arrhythmia|irregular heart rhythm]], fatigue, shortness of breath, [[Wheeze|wheezing]], leg cramps, or [[claudication|any impairment in walking or pain, discomfort, numbness, or tiredness in the legs]].<ref name=Circulation2013/>

Exercise is performed on a treadmill. The leads of the Ecg are placed on the chest wall. The treadmill is started at 2.74km/hr (1.7mph) & at an inclined gradient of 10%
After 3 min incline of the treadmill is increased by 2%, and the speed increases .
The test should be stopped ,when the subject cannot continue due to fatigue or pain or due to any other medical condition .


===Stages===
===Stages===
Stages of the standard Bruce protocol are as follows:<ref name="Circulation2013">{{cite journal |last1=Fletcher |first1=Gerald F. |last2=Ades |first2=Philip A. |last3=Kligfield |first3=Paul |last4=Arena |first4=Ross |last5=Balady |first5=Gary J. |last6=Bittner |first6=Vera A. |last7=Coke |first7=Lola A. |last8=Fleg |first8=Jerome L. |last9=Forman |first9=Daniel E. |last10=Gerber |first10=Thomas C. |last11=Gulati |first11=Martha |last12=Madan |first12=Kushal |last13=Rhodes |first13=Jonathan |last14=Thompson |first14=Paul D. |last15=Williams |first15=Mark A. |title=Exercise Standards for Testing and Training: A Scientific Statement From the American Heart Association |journal=Circulation |date=20 August 2013 |volume=128 |issue=8 |pages=873–934 |doi=10.1161/CIR.0b013e31829b5b44|pmid=23877260 }}</ref>
{| class="wikitable"
* Level 1 - 10% Incline at 2.7 km/h
* Level 2 - 12% Incline at 4.02 km/h
* Level 3 - 14% Incline at 5.47 km/h
* Level 4 - 16% Incline at 6.76 km/h
* Level 5 - 18% Incline at 8.05 km/h
* Level 6 - 20% Incline at 8.85 km/h
* Level 7 - 22% Incline at 9.65 km/h
* Level 8 - 24% Incline at 10.46 km/h
* Level 9 - 26% Incline at 11.26 km/h
* Level 10 - 28% Incline at 12.07 km/h

==Result==

Measuring VO2 Max With the Bruce Protocol
Maximal oxygen uptake (VO2 max) refers to the maximum amount of oxygen that an individual can take in and use during intense or maximal exercise.3 It is measured as milliliters of oxygen used in one minute per kilogram of body weight (ml/kg/min).
The Bruce treadmill test is an indirect maximal oxygen uptake test. It is considered indirect because it estimates VO2 max using a formula and the person's performance on a treadmill as the workload is increased.

==Advantage==

MHR( maximum heart rate 220-age)by recording HR during test which can be used in training programs to set intensity.

==Disadvantage==

Large time and cost require and specilised training for exercise ECG tracing.

==History==
Before the development of the Bruce protocol there was no safe, standardized protocol that could be used to monitor [[cardiac]] function in exercising patients. Master's Two-Step test was sometimes used, but it was too strenuous for many patients, and inadequate for the assessment of [[Respiratory system|respiratory]] and [[Circulatory system|circulatory]] function during varying amounts of exercise. Most physicians relied upon patients' complaints about exertion, and examined them only at rest.{{cn|date=March 2021}}

To address these problems, Bruce and his colleagues began to develop a [[cardiac stress test]]. The test made extensive use of relatively new technological developments in [[Electrocardiography#Electrocardiograph machines|electrocardiograph machines]] and motorized [[treadmill]]s. The Bruce exercise test involved walking on a treadmill while the heart was monitored by an electrocardiograph with various [[electrode]]s attached to the body. [[Breathing]] volumes and respiratory [[gas exchange]] were also monitored before, during and after exercise. Because the treadmill speed and inclination could be adjusted, this physical activity was tolerated by most patients. Initial experiments involved a single-stage test, in which subjects walked for 10 minutes on the treadmill at a fixed workload. Bruce's first reports on treadmill exercise tests, published in 1949, analyzed minute-by-minute changes in respiratory and circulatory function of normal adults and patients with heart or lung disease.<ref>{{cite journal|author1=Robert A. Bruce|author2=Frank W. Lovejoy Jr.|author3=Raymond Pearson|author4=Paul N. G. Yu|author5=George B. Brothers|author6=Tulio Velasquez|title=Normal respiratory and circulatory pathways of adaptation in exercise|journal=J Clin Invest|volume=28|issue=6 Pt 2|pages=1423–30|year=1949|doi=10.1172/JCI102207|pmid=15407661|pmc=439698}}</ref><ref>{{cite journal|author1=Robert A. Bruce|author2=Raymond Pearson|author3=Frank W. Lovejoy Jr.|author4=Paul N. G. Yu|author5=George B. Brothers|title=Variability of respiratory and circulatory performance during standardized exercise|journal=J Clin Invest|volume=28|issue=6 Pt 2|pages=1431–8|year=1949|doi=10.1172/JCI102208|pmid=15395945|pmc=439699}}</ref>

In 1950 Bruce joined the [[University of Washington]], where he continued research on the single-stage test, particularly as a predictor of the success of surgery for [[Valvular heart disease|valvular]] or [[Congenital heart defect|congenital]] heart disease. Later he developed a multistage test, consisting of several stages of progressively greater workloads. It was this multistage test — a description of which was first published in 1963 — that became known as the Bruce Protocol. In the initial paper, Bruce reported that the test could detect signs of such conditions as [[Angina|angina pectoris]], a previous [[Myocardial infarction|heart attack]], or a ventricular [[aneurysm]]. Bruce and his colleagues also demonstrated that exercise testing was useful in screening apparently healthy people for early signs of coronary artery disease.{{cn|date=March 2021}}

Typically during a Bruce Protocol, heart rate and rating of perceived exertion are taken every minute and blood pressure is taken at the end of each stage (every three minutes). There are Bruce protocol tables available for maximal (competitive athletes) and sub-maximal (non-athletic people) efforts{{cn|date=March 2021}} (see below).

{| border=1 cellspacing=0 cellpadding=2

|-
! Stage
! Stage
! title="duration in minutes" | Minutes
! title="duration in minutes" | Minutes
Line 109: Line 43:
!min/km
!min/km
! [[Metabolic equivalent|MET]]S
! [[Metabolic equivalent|MET]]S
!m/s
|-
|-
| 1 || 3 || 10 || 1.7
| 1 || 3 || 10 || 1.7
|35:18|| 2.7
|35:18|| 2.7
|22:13|| 3
|22:13|| 3
|0.75
|-
|-
| 2 || 3 || 12 || 2.5
| 2 || 3 || 12 || 2.5
|24:00|| 4.0
|24:00|| 4.0
|15:00|| 4-5
|15:00|| 4-5
|1.11
|-
|-
| 3 || 3 || 14 || 3.4
| 3 || 3 || 14 || 3.4
|17:39|| 5.5
|17:39|| 5.5
|10:55|| 7
|10:55|| 7
|1.52
|-
|-
| 4 || 3 || 16 || 4.2
| 4 || 3 || 16 || 4.2
|14:17|| 6.8
|14:17|| 6.8
|8:49|| 10
|8:49|| 10
|1.89
|-
|-
| 5 || 3 || 18 || 5.0
| 5 || 3 || 18 || 5.0
|12:00|| 8.0
|12:00|| 8.0
|7:30|| 14
|7:30|| 14
|2.22
|-
|-
| 6 || 3 || 20 || 5.5
| 6 || 3 || 20 || 5.5
|10:55|| 8.9
|10:55|| 8.9
|6:44|| 17
|6:44|| 17
|2.47
|-
|-
| 7 || 3 || 22 || 6.0
| 7 || 3 || 22 || 6.0
|10:00|| 9.7
|10:00|| 9.7
|6:11||21
|6:11||21
|2.69
|}
|}
Total Duration = 21 minutes
Total Duration = 21 minutes

==History==
{{sectionrefimprove|date=August 2023}}
Before the development of the Bruce protocol there was no safe, standardized protocol that could be used to monitor cardiac function in exercising patients. Master's two-step test<ref name="Master1935">{{cite journal |last1=Master |first1=Arthur M. |title=The two-step test of myocardial function |journal=American Heart Journal |date=April 1935 |volume=10 |issue=4 |pages=495–510 |doi=10.1016/S0002-8703(35)90218-6}}</ref> was often used, but it was too strenuous for many patients, and inadequate for the assessment of [[Respiratory system|respiratory]] and [[Circulatory system|circulatory]] function during varying amounts of exercise.

To address these problems, Bruce and his colleagues began to develop a [[cardiac stress test]]. The test made extensive use of relatively new technological developments in [[Electrocardiography#Electrocardiograph machines|electrocardiograph machines]] and motorized [[treadmill]]s. The Bruce exercise test involved walking on a treadmill while the heart was monitored by an electrocardiograph with various [[electrode]]s attached to the body. [[Breathing]] volumes and respiratory [[gas exchange]] were also monitored before, during and after exercise. Because the treadmill speed and inclination could be adjusted, this physical activity was tolerated by most patients. Initial experiments involved a single-stage test, in which subjects walked for 10 minutes on the treadmill at a fixed workload. Bruce's first reports on treadmill exercise tests, published in 1949, analyzed minute-by-minute changes in respiratory and circulatory function of normal adults and patients with heart or lung disease.<ref>{{cite journal|author1=Robert A. Bruce|author2=Frank W. Lovejoy Jr.|author3=Raymond Pearson|author4=Paul N. G. Yu|author5=George B. Brothers|author6=Tulio Velasquez|title=Normal respiratory and circulatory pathways of adaptation in exercise|journal=J Clin Invest|volume=28|issue=6 Pt 2|pages=1423–30|year=1949|doi=10.1172/JCI102207|pmid=15407661|pmc=439698}}</ref><ref>{{cite journal|author1=Robert A. Bruce|author2=Raymond Pearson|author3=Frank W. Lovejoy Jr.|author4=Paul N. G. Yu|author5=George B. Brothers|title=Variability of respiratory and circulatory performance during standardized exercise|journal=J Clin Invest|volume=28|issue=6 Pt 2|pages=1431–8|year=1949|doi=10.1172/JCI102208|pmid=15395945|pmc=439699}}</ref>

In 1950 Bruce joined the [[University of Washington]], where he continued research on the single-stage test, particularly as a predictor of the success of surgery for [[Valvular heart disease|valvular]] or [[Congenital heart defect|congenital]] heart disease. Later he developed a multistage test, consisting of several stages of progressively greater workloads. It was this multistage test — a description of which was first published in 1963 — that became known as the Bruce Protocol. In the initial paper, Bruce reported that the test could detect signs of such conditions as [[Angina|angina pectoris]], a previous [[Myocardial infarction|heart attack]], or a ventricular [[aneurysm]]. Bruce and his colleagues also demonstrated that exercise testing was useful in screening apparently healthy people for early signs of coronary artery disease.{{cn|date=March 2021}}

Typically during a Bruce Protocol, heart rate and rating of perceived exertion are taken every minute and blood pressure is taken at the end of each stage (every three minutes). There are Bruce protocol tables available for maximal (competitive athletes) and sub-maximal (non-athletic people) efforts.{{cn|date=March 2021}}


===Modifications===
===Modifications===
{{sectionrefimprove|date=August 2023}}
The Modified Bruce protocol starts at a lower workload than the standard test and is typically used for elderly or sedentary patients. The first two stages of the Modified Bruce Test are performed at a 1.7&nbsp;mph and 0% grade and 1.7&nbsp;mph and 5% grade, and the third stage corresponds to the first stage of the Standard Bruce Test protocol as listed above.{{cn|date=March 2021}}
The Modified Bruce protocol starts at a lower workload than the standard test and is typically used for elderly or sedentary patients. The first two stages of the Modified Bruce Test are performed at a 1.7&nbsp;mph and 0% grade and 1.7&nbsp;mph and 5% grade, and the third stage corresponds to the first stage of the Standard Bruce Test protocol as listed above.{{cn|date=March 2021}}


===Results===
===Results===
{{sectionrefimprove|date=August 2023}}
The test score is the time taken on the test, in minutes. This can also be converted to an estimated [[VO2 max|maximal oxygen uptake]] 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.{{cn|date=March 2021}}
The test score is the time taken on the test, in minutes. This can also be converted to an estimated [[VO2 max|maximal oxygen uptake]] 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.{{cn|date=March 2021}}
* VO2max (ml/kg/min) = 14.76 - (1.379 × T) + (0.451 × T²) - (0.012 × T³)
* VO2max (ml/kg/min) = 14.76 - (1.379 × T) + (0.451 × T²) - (0.012 × T³)
Line 153: Line 107:


===Underlying Heart Rate Formulas===
===Underlying Heart Rate Formulas===
[[Maximum heart rate]] (MHR) is often calculated with the formula 220-age, which is quite inaccurate. The heart rate formula most often used for the Bruce is the Karvonen formula (below).
[[Maximum heart rate]] (MHR) is often calculated with the formula 220-age, which is quite inaccurate.{{cn|date=April 2024}} The heart rate formula most often used for the Bruce is the Karvonen formula (below).


A more accurate formula, offered in a study published in the journal, Medicine & Science in Sports & Exercise, is 206.9 - (0.67 x age) which can also be used to more accurately determine VO2 Max, but may produce significantly different results.
A more accurate formula, offered in a study published in the journal, Medicine & Science in Sports & Exercise, is 206.9 - (0.67 x age) which can also be used to more accurately determine VO2 Max, but may produce significantly different results.{{cn|date=April 2024}}


A diagnostician (e.g., physical therapist, personal trainer, doctor, athletic trainer, nurse, medical professional, dietitian, etc.) may be best served to conduct the test twice using both parameters and formulas.
A diagnostician (e.g., physical therapist, personal trainer, doctor, athletic trainer, nurse, medical professional, dietitian, etc.) may be best served to conduct the test twice using both parameters and formulas.


===Karvonen method===
===Karvonen method===
The ''Karvonen method'' factors in resting heart rate (HR<sub>rest</sub>) to calculate target heart rate (THR), using a range of 50–85%:{{cn|date=March 2021}}
The ''Karvonen method'' factors in resting heart rate (HR<sub>rest</sub>) to calculate [[target heart rate]] (THR), using a range of 50–85% intensity:<ref>{{cite journal |vauthors=Karvonen J, Vuorimaa T |title=Heart rate and exercise intensity during sports activities. Practical application |journal=Sports Medicine |volume=5 |issue=5 |pages=303–11 | date=May 1988 |pmid=3387734 |doi=10.2165/00007256-198805050-00002|s2cid=42982362 }}</ref>

:THR = ((HR<sub>max</sub> − HR<sub>rest</sub>) × %Intensity) + HR<sub>rest</sub>
:THR = ((HR<sub>max</sub> − HR<sub>rest</sub>) × %Intensity) + HR<sub>rest</sub>


Example for someone with a HR<sub>max</sub> of 180 and a HR<sub>rest</sub> of 70:<br>
Example for someone with a HR<sub>max</sub> of 180 and a HR<sub>rest</sub> of 70:

50% intensity: ((180 − 70) × 0.50) + 70 = 125 bpm<br>
85% intensity: ((180 − 70) × 0.85) + 70 = 163 bpm
* 50% intensity: ((180 − 70) × 0.50) + 70 = 125 bpm
* 85% intensity: ((180 − 70) × 0.85) + 70 = 163 bpm


==References==
==References==
Line 174: Line 128:


{{DEFAULTSORT:Bruce Protocol}}
{{DEFAULTSORT:Bruce Protocol}}
[[Category:Cardiac procedures]]
[[Category:Diagnostic cardiology]]
[[Category:Exercise physiology]]
[[Category:Exercise physiology]]

Latest revision as of 21:22, 17 April 2024

Bruce protocol
Treadmill for functional diagnostics for competitive athletes (1980)
Purposeevaluate cardiac function
Test ofCardiac stress test

The Bruce protocol is a standardized diagnostic test used in the evaluation of cardiac function and physical fitness, developed by American cardiologist Robert A. Bruce.[1]

According to the original Bruce protocol the patient walks on an uphill treadmill in a graded exercise test with electrodes on the chest to monitor. Every 3 min the speed & incline of the treadmill are increased.[2] There are 7 such stages and only very fit athletes can complete all 7 stages. The modified Bruce Protocol is an alteration in the protocol so that the treadmill is initially horizontal rather than uphill, with the 1st few intervals increasing the treadmill slope only.[3]

The Bruce treadmill test estimates maximum oxygen uptake using a formula and the performance of the subject on a treadmill as the workload is increased. The test is easy to perform in a medical office setting, does not require extensive training or expensive equipment, and it has been validated as a strong predictor of clinical outcomes.[4]

Procedure

[edit]

Exercise is performed on a treadmill. The leads of the ECG are placed on the chest wall. The treadmill is started at 2.74 km/h (1.7mph) & at an inclined gradient of 10%. After 3 min incline of the treadmill is increased by 2%, and the speed increases. Indications to terminate the test include signs or symptoms of impaired blood flow to the heart, irregular heart rhythm, fatigue, shortness of breath, wheezing, leg cramps, or any impairment in walking or pain, discomfort, numbness, or tiredness in the legs.[5]

Stages

[edit]

Stages of the standard Bruce protocol are as follows:[5]

Stage Minutes % grade MPH min/mile km/h min/km METS m/s
1 3 10 1.7 35:18 2.7 22:13 3 0.75
2 3 12 2.5 24:00 4.0 15:00 4-5 1.11
3 3 14 3.4 17:39 5.5 10:55 7 1.52
4 3 16 4.2 14:17 6.8 8:49 10 1.89
5 3 18 5.0 12:00 8.0 7:30 14 2.22
6 3 20 5.5 10:55 8.9 6:44 17 2.47
7 3 22 6.0 10:00 9.7 6:11 21 2.69

Total Duration = 21 minutes

History

[edit]

Before the development of the Bruce protocol there was no safe, standardized protocol that could be used to monitor cardiac function in exercising patients. Master's two-step test[6] was often used, but it was too strenuous for many patients, and inadequate for the assessment of respiratory and circulatory function during varying amounts of exercise.

To address these problems, Bruce and his colleagues began to develop a cardiac stress test. The test made extensive use of relatively new technological developments in electrocardiograph machines and motorized treadmills. The Bruce exercise test involved walking on a treadmill while the heart was monitored by an electrocardiograph with various electrodes attached to the body. Breathing volumes and respiratory gas exchange were also monitored before, during and after exercise. Because the treadmill speed and inclination could be adjusted, this physical activity was tolerated by most patients. Initial experiments involved a single-stage test, in which subjects walked for 10 minutes on the treadmill at a fixed workload. Bruce's first reports on treadmill exercise tests, published in 1949, analyzed minute-by-minute changes in respiratory and circulatory function of normal adults and patients with heart or lung disease.[7][8]

In 1950 Bruce joined the University of Washington, where he continued research on the single-stage test, particularly as a predictor of the success of surgery for valvular or congenital heart disease. Later he developed a multistage test, consisting of several stages of progressively greater workloads. It was this multistage test — a description of which was first published in 1963 — that became known as the Bruce Protocol. In the initial paper, Bruce reported that the test could detect signs of such conditions as angina pectoris, a previous heart attack, or a ventricular aneurysm. Bruce and his colleagues also demonstrated that exercise testing was useful in screening apparently healthy people for early signs of coronary artery disease.[citation needed]

Typically during a Bruce Protocol, heart rate and rating of perceived exertion are taken every minute and blood pressure is taken at the end of each stage (every three minutes). There are Bruce protocol tables available for maximal (competitive athletes) and sub-maximal (non-athletic people) efforts.[citation needed]

Modifications

[edit]

The Modified Bruce protocol starts at a lower workload than the standard test and is typically used for elderly or sedentary patients. The first 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.[citation needed]

Results

[edit]

The test score is the time taken on the test, in minutes. This can also be converted to an estimated maximal oxygen uptake 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.[citation needed]

  • VO2max (ml/kg/min) = 14.76 - (1.379 × T) + (0.451 × T²) - (0.012 × T³)
  • Women: VO2max (ml/kg/min) = 2.94 x T + 3.74
  • Young 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

ref: ACSM's Health-Related Physical Fitness Assessment Manual

Underlying Heart Rate Formulas

[edit]

Maximum heart rate (MHR) is often calculated with the formula 220-age, which is quite inaccurate.[citation needed] The heart rate formula most often used for the Bruce is the Karvonen formula (below).

A more accurate formula, offered in a study published in the journal, Medicine & Science in Sports & Exercise, is 206.9 - (0.67 x age) which can also be used to more accurately determine VO2 Max, but may produce significantly different results.[citation needed]

A diagnostician (e.g., physical therapist, personal trainer, doctor, athletic trainer, nurse, medical professional, dietitian, etc.) may be best served to conduct the test twice using both parameters and formulas.

Karvonen method

[edit]

The Karvonen method factors in resting heart rate (HRrest) to calculate target heart rate (THR), using a range of 50–85% intensity:[9]

THR = ((HRmax − HRrest) × %Intensity) + HRrest

Example for someone with a HRmax of 180 and a HRrest of 70:

  • 50% intensity: ((180 − 70) × 0.50) + 70 = 125 bpm
  • 85% intensity: ((180 − 70) × 0.85) + 70 = 163 bpm

References

[edit]
  1. ^ Kennedy JW, Cobb LA, Samson WE (10 May 2005). "Robert Arthur Bruce, MD: 1916–2004". Circulation. 111 (18): 2410–2411. doi:10.1161/01.CIR.0000164274.41137.75. PMID 16389672.
  2. ^ Bruce, RA (December 1971). "Exercise testing of patients with coronary heart disease. Principles and normal standards for evaluation". Annals of Clinical Research. 3 (6): 323–32. PMID 5156892.
  3. ^ Sheffield, L.Thomas; Roitman, David (July 1976). "Stress testing methodology". Progress in Cardiovascular Diseases. 19 (1): 33–49. doi:10.1016/0033-0620(76)90007-4. PMID 785541.
  4. ^ Kelly, Jacob P.; Andonian, Brian J.; Patel, Mahesh J.; Huang, Zhen; Shaw, Linda K.; McGarrah, Robert W.; Borges-Neto, Salvador; Velazquez, Eric J.; Kraus, William E. (April 2019). "Trends in Cardiorespiratory Fitness: The Evolution of Exercise Treadmill Testing at a Single Academic Medical Center from 1970 to 2012". American Heart Journal. 210: 88–97. doi:10.1016/j.ahj.2019.01.001. PMC 6441626. PMID 30743212.
  5. ^ a b Fletcher, Gerald F.; Ades, Philip A.; Kligfield, Paul; Arena, Ross; Balady, Gary J.; Bittner, Vera A.; Coke, Lola A.; Fleg, Jerome L.; Forman, Daniel E.; Gerber, Thomas C.; Gulati, Martha; Madan, Kushal; Rhodes, Jonathan; Thompson, Paul D.; Williams, Mark A. (20 August 2013). "Exercise Standards for Testing and Training: A Scientific Statement From the American Heart Association". Circulation. 128 (8): 873–934. doi:10.1161/CIR.0b013e31829b5b44. PMID 23877260.
  6. ^ Master, Arthur M. (April 1935). "The two-step test of myocardial function". American Heart Journal. 10 (4): 495–510. doi:10.1016/S0002-8703(35)90218-6.
  7. ^ Robert A. Bruce; Frank W. Lovejoy Jr.; Raymond Pearson; Paul N. G. Yu; George B. Brothers; Tulio Velasquez (1949). "Normal respiratory and circulatory pathways of adaptation in exercise". J Clin Invest. 28 (6 Pt 2): 1423–30. doi:10.1172/JCI102207. PMC 439698. PMID 15407661.
  8. ^ Robert A. Bruce; Raymond Pearson; Frank W. Lovejoy Jr.; Paul N. G. Yu; George B. Brothers (1949). "Variability of respiratory and circulatory performance during standardized exercise". J Clin Invest. 28 (6 Pt 2): 1431–8. doi:10.1172/JCI102208. PMC 439699. PMID 15395945.
  9. ^ Karvonen J, Vuorimaa T (May 1988). "Heart rate and exercise intensity during sports activities. Practical application". Sports Medicine. 5 (5): 303–11. doi:10.2165/00007256-198805050-00002. PMID 3387734. S2CID 42982362.
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