Transcript Graded Exercise Tests GXTs

Graded Exercise Tests
GXTs
A multistage test that determines a
person’s physiological responses to
different intensities of exercise and/or
the person’s peak aerobic capacity
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When to use
submaximal and maximal tests
Load
Heart
Cardiovascular response
Evaluate CRF in
fitness program for
healthy population
Submaximal
Evaluate cardiovascular
fitness prior to and following
a fitness program
Changes occur in ECG
Clinical assessment of
coronary heart disease
Maximal test
to determine the presence
of CHD in asymptomatic
individual
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Maximal GXT
*a diagnostic, functional capacity test is mandatory for all
people in the high-risk category who want to start an
exercise program.
* usually done with a treadmill or cycle ergometer
Purposes of Maximal GXT with ECG
To diagnose overt or latent heart disease
•To evaluate cardiorespiratory functional capacity
•To evaluate response to conditioning or
•cardiac-rehabilitation program
•To increase individual motivation for entering and adhering
•to exercise program
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Your fitness center is responsible for
both fitness program and fitness testing..
Maximal GXT
Submaximal GXT
Inactive person
Discomfort from the test
Discourage from
participating in fitness
program
Find fewer
abnormal
responses
Inaccurate
estimate VO2max
Suggestion: in a fitness program for apparently healthy people,
administer submaximal test early and conduct a maximal test until
the participant has been involved in a regular exercise program
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More about submaximal and maximal GXT
Typically, Health/ fitness Instructor uses Sub- to estimate
a person’s VO2max
Predicted VO2max from any submaximal test involves error
Only way to determine true functional capacity is to measure it
during a maximal test
Changes in HR, BP and RPE as a result of an exercise program
make a submaximal test a good mechanism for showing
improvements in CRF
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Any of GXT protocols can be used for submaximal or
maximal testing - the only difference is the criteria for
stopping the test
Test is stopped if
any of the abnormal
responses
Absence of
abnormal responses
Submaximal
when target HR
reached
often 85% of HRmax
Maximal
when a state of
voluntary exhaustion
reached
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Guidelines for Exercise Test
Administration
Medical evaluation prior to testing
medical history
physical examination
Contraindication to testing
General principles of exercise testing
Test protocols
Informed consent
Preparation for ECG monitoring
Conducting the test
Interpretation of the exercise test
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Contraindications for Exercise
and Exercise Testing
P58 table 3.3
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General principles of exercise
testing
1. If there is any doubt as to the benefit of testing or the safety of
testing, the test should not be performed at that time.
2. The test protocol should be selected to accommodate the
individual patients ability to perform treadmill exercise or cycle
ergometer.
3. The exercise test should begin at a MET level intensity
considerably below the anticipated limitation or maximal capacity
and increase gradually in 2- or 3-minute stages, with observation
made at each different stage. The increase in intensity at each stage
may be as large as 2 to 3 METs in healthy population or as small
as 1/2 MET in those with disease.
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4. Heart rate, blood pressure, rating of perceived exertion (RPE)
and patient appearance and symptoms should be monitored
regularly.
5. Contraindications for testing and indication for stopping exercise
should be closely observed.
6. All observations should be continued for at least 4 minutes on
recovery unless abnormal responses occur which would require
a longer post-test observation.
7. The testing area should be 22C (72F)or less and the humidity
60% or less if possible.
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Steps to Administering a GXT
P219,
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Maximal Exercise Test Protocols
No one GXT protocol is appropriate for all types of people
Young active
Start
6 METs
Increment 2-3 METs
per stage
Sedentary
4 METs
2 METs
1-2 METs
0.5-1 METs
Compare CRF
Time per stage
Questionable health status
1-2 minutes
Predict VO2max
2-3 minutes
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Testing Protocol for Different Groups
P 220 T 11.6
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Submaximal Treadmill Test Protocols
Balke Standard Protocol
3.5 mph, 2.5% grade increase every 2 minutes
Heart rate monitored in the last 30s of each stage
Test terminated at 85% of age-adjusted maximal heart rate
Maximal aerobic power estimated by extrapolating the HR
response to the person’s estimated maximal heart rate
The heart rate response is usually quite linear between
110 beats/min and the subject’s 85% of maximal HR cutoff
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Submaximal Cycle Ergometer Test
Protocols
p223
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Submaximal Cycle Ergometer Test
Protocols
A linear relationship between HR and work rate (VO2) once
a HR of approximately 110 beats/min is reached
The subject is required to complete one more stage past the one
causing HR of 110 beats/min
Each stage lasts 3 minutes , unless a subject’s HR has not reached
a steady state (greater than 5 beats/min difference between 2nd
and 3rd-min HR). In that case, an extra minute is added to that stage
the pedal rate is maintained at 50 rev/min, so that, on a Monark cycle,
a 0.5-kp increase in load is equal to 150 kpm/min (25W)
50 rev/min X 6 meters/rev X 1 kp = 300 kg.m/min
1 watt = 6.0 kg.m/min
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1 kp = I kilopond = kilogram
Submaximal Cycle Ergometer Test
Protocols
Seat height is adjusted so that the knee is slightly bent (50)
when the pedal is at the bottom of the swing through 1 revolution
seat height is recorded
HR is monitored during the later half of the 2nd and 3rd min of
each stage
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Guide for setting workloads for men and women on
YMCA submaximal cycle ergometer test
P224 f 11.4
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A sample of
YMCA submaximal cycle ergometer test
P224 correction factor
p225 f11.5 and In review
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