Transcript Cardiorespiratory Testing

Cardiorespiratory Testing
Maximal Oxygen Uptake
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• AKA VO2 Max
• Criterion measure of cardiorespiratory
fitness
• Product of maximal cardiac output and
arterial-venous oxygen difference
• Directly related to functional capacity of the
heart
Maximal Oxygen Uptake
• Direct measurement
– Open-circuit spirometry
• Pulmonary ventilation
• Expired O2 and CO2 fractions
Maximal Oxygen Uptake
• Indirect methods
– Estimation techniques
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– VO2 values correlated with intensities reached
• Similarities in fitness levels
• Similarities in age and gender
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• Regression equations used to predict VO2
Maximal Oxygen Uptake
• Indirect methods
– Estimation techniques
• Step tests
– Little equipment or skill needed
– Short duration test – less than 5 minutes
– Requires some balance
– Difficult for extremely deconditioned
Maximal Oxygen Uptake
• Indirect methods
– Estimation techniques
• Field tests – practical (mass testing)
– Cooper 12 minute run
» Requires maximal effort & motivation
» Unmonitored – danger for at-risk?
– Rockport 1 mile walk
» Requires maximal effort & motivation
» Unmonitored but walking vs. running decreases danger
Maximal Oxygen Uptake
• Indirect methods
– Estimation techniques
• Treadmill tests
– Accommodates all fitness levels – speed changes
– Requires skill and balance for some – practice?
– Difficult to measure BP
Maximal Oxygen Uptake
• Indirect methods
– Estimation techniques
• Cycle ergometer tests
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Easy to take BP measurements
Non weight bearing – accommodates extremely weak
Small work rate adjustments can be made
Familiar skill – but not a common activity
– Severe localized fatigue - motivation
– Specific pedal cadence is required - motivation
Maximal Oxygen Uptake
• Maximal Exercise Tests
– Advantage
• True maximal capacity can be measured
• Increased sensitivity in Dx of CAD in asymptomatic
– Disadvantage
• Volitional fatigue
– do they know maximum?
– risk of injury
• Physician supervision*
• Emergency equipment*
Maximal Oxygen Uptake
• Maximal Exercise Tests
– Incremental workloads
– Steady state not required
• “Quick and dirty”
• Just max is the goal
– Prolonged – other measures along the way
• Ventilatory threshold
• Lactate threshold
Maximal Oxygen Uptake
• Submaximal Exercise Tests
– Assumptions
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Steady is state reached at each work rate
Linear relationship between HR and work rate
Maximal HR is uniform for every age
Predict max from slope of line
Submaximal Testing
• Keys to success
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2-3 min warm-up and equipment acquaintance
Monitor HR & BP near the end of each stage
Perceived exertion (6-20 or 1-10 scale)
Monitor subject’s/client’s appearance
Terminate at 85% of age-predicted max HR, or
70% of HR reserve, or if problems arise
– Allow warm-down & monitor
Submaximal Testing
• Test Termination Criteria in Low-risk adults (Box 4-5)
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***Subject requests to stop***
**Failure of testing equipment**
Onset of angina – pain associated with ischemia
Significant rise or drop in BP
Signs of poor perfusion – pallor
Failure of HR to increase with workload increase
Noticeable change in heart rhythm
Severe fatigue
Submaximal Testing
• Cycle Ergometer Tests
– Astrand-Rhyming Cycle Ergometer Test (page 70)
• Single stage test – target HR from 125-170
• Work Rate – (@ 50 rpm)
– Men – unfit 300 or 600, fit 600 or 900 kgm/min
– Women – unfit 300 or 450, fit 450 or 600 kgm/min
• Heart rate taken @ 5th & 6th min. – average them
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• Use of nomogram
to estimate max VO2 (Figure 4-1)
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• Correct VO2 max by multiplying correction factor for age
difference in max HR
Submaximal Testing
• Cycle Ergometer Tests
– YMCA Cycle Ergometry Test (page 74)
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2 - 4 stage continuous exercise
Branching – if ___ Hr, then ___ intensity
Heart rate taken @ 2nd & 3rd min. of each stage
HR must be within 6 beats to go to next stage
HR must be between 110 and 85% age predicted max
Plot HRs of last min. then extrapolate to max HR
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Line to predicted work rate at max VO2
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Calculate a predicted VO2 (Appendix D)
Prediction Line
Max HR
220-age
Submax 2
Submax 1
Max Work Rate
Work Rate
Evaluation of Results
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• Compare predicted VO2 to norm table (table
4-8)
Example
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Male, Age = 45
1st stage yields HR of 98
2nd stage yields HR of 121
3rd stage yields HR of 143
Age predicted max HR = 175
85% of max HR = 149
Predicted max = ? Plot to find
Example
• Use graph to plot predicted work rate at max
HR
• Used predicted max
work rate for calculation of
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predicted max VO2
Maximal Testing
• Purpose
– Diagnosis of CAD
– Prognosis of client regarding disease
– Finding functional capacity for prescription
(CRF – Cardiorespiratory Function)
• Physician Supervised?
– Low risk & men < 45 yr / women < 55 yr
– Moderate & High risk
Maximal Testing
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Personnel
– “Experienced paramedical personnel”
– ACSM Exercise Specialist Certified? KSA’s
1. Exercise Physiology and Related Exercise Science
2. Pathophysiology and Risk Factors
3. Health Appraisal, Fitness and Clinical Exercise Testing
4. Electrocardiography and Diagnostic Techniques
5. Patient Management and Medications
6. Medical and Surgical Management
7. Exercise Prescription and Programming
8. Nutrition and Weight Management
9. Human Behavior and Counseling
10. Safety, injury Prevention, and Emergency Procedures
11. Program Administration, Quality Assurance, and Outcome
Assessment
Maximal Testing
• Work Rate Changes
– Incremental Format
• 1 minute – 3 minutes
• Large intensity changes
• Time to reach steady state
– Ramp Format
• ~ 20 sec stages
• Small intensity changes
• Smoother – non-steady state
Maximal Testing
• Clinical
– Treadmill
• Bruce Protocol
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most common
large metabolic demand increments
best for more fit subjects
3 min stages
increases in speed & grade
Maximal Testing
• Clinical
– Treadmill
• Balke-Ware
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small work increments
best for less fit subjects
1 min stages
speed remains at 3.3 mph
increases in grade only by 1% each stage
Maximal Testing
• Sequence of Measures
– HR (ECG), BP, RPE, Familiarization, Termination
– Box 4-4
• Pre
• Exercise
• Posttest
Maximal Testing
• Indications for Terminating Test
– Absolute
• Decreased medical status
• Equipment Failure
• Request to stop
– Relative
• Change in hemodynamic function
• Change in ECG
• Fatigue / Chest Pain
Maximal Testing
• Symptomatic
– Angina Scale
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1+
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4+
Light, barely noticeable
Moderate, bothersome
Moderately severe, very uncomfortable
Most severe or intense pain ever experienced
– A 3+ would indicate stopping a test
Maximal Testing
• Functional Aerobic Impairment
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– %FAI = (Predicted VO2 – Observed VO2) x 100
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Predicted VO2
Maximal Testing
• Metabolic Equivalents
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METs
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• Multiples of VO2 at rest - 3.5 ml/kg/min
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• Predicted average max VO2 in METs
– Men= (57.5 - .445 x age) / 3.5
– Women= (42.3 - .356 x age) / 3.5
Maximal Testing
• Performance
– Determine functional capacity
• Velocity at max for prescription and program assessment
• HR at max for prescription and program assessment
• Power at max for prescription and program assessment
Maximal Testing
• Performance
– Methods
• Max only
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“Quick & dirty” – rapid rise in intensity until max
8- 12 minutes of testing
No need for steady state
max is goal without fatigue from time
Maximal Testing
• Treadmill
– Protocol
• Ramp or incremental stages
• Alternate speed and / or grade
• Limitation should be physiological not
psychological
Maximal Testing
• Cycle Ergometer
– Protocol
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Ramp or incremental stages
Maintain pedal cadence
Increase tension
Seated & legs only – no standing or arm assistance
Limitation should be physiological not
psychological
Maximal Testing
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Max VO2 Determination Criteria
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Caveat 1. Use of large muscle groups
Caveat 2. Activity specific to “athlete’s” sport
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No increase in VO2 with increase in work rate
RER > 1.15
HR during final stage + 10 beats of predicted HR
Blood lactate concentration > 8 mmoles/liter
VO2 (ml/kg/min)
Max VO2
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Work Rate
Maximal Testing
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• PEAK VO2
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– Highest VO2 reached without meeting caveats
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– Highest VO2 reached without meeting 2 of 3
criteria
Maximal Testing
• Threshold Determination
– OBLA – rapid blood lactate accumulation
– T-vent - non-linear ventilation increase
– Protocol
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Smaller intensity increments – not too small!
Even intensity increments
Minute by minute measures – “catch” the inflection point
May last too long to achieve max (fatigue)
Ventilation (ml/min)
Ventilatory Threshold
T-vent
Work Rate
Supra-maximal Testing
• Wingate Anaerobic Power Test
– Energy supply beyond aerobic metabolism
– Protocol
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Cycle ergometer
30 second ride at maximal cadence
Load = 7.5% to 10% of body mass (kg)
Determines peak power (watts)
Determines average power
Determines %Power Decline
Supra-maximal Testing
• Wingate Anaerobic Power Test
– Indices
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Phosphagen stores
Glycolytic system
Buffering capacity
Motivation & capacity to tolerate discomfort
“Kick” at the end of a race or surge during the race
Power to weight ratio (relative power)
Questions?
End