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Assessing Cardiorespiratory Endurance. A Fitness Indicator. Determination of Fitness Level. Everyone possesses some degree of cardiorespiratory endurance (CRE)

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determination of fitness level
Determination of Fitness Level
  • Everyone possesses some degree of cardiorespiratory endurance (CRE)
  • CRE=a health associated component that relates to the ability of circulatory and respiratory systems to supply fuel during sustained physical activity and to eliminate fatigue products after supplying fuel.
vo 2 max
VO2 max
  • VO2 max is the most commonly used index to assess CRE
  • Definition - The largest amount of oxygen that an individual can utilize during strenuous exercise to complete exhaustion
  • Has become the accepted measure of CRE
vo 2 max1
VO2 max
  • Units
    • liters/minute or ml/minute (absolute)
    • ml/kg/min (relative to body weight)
    • ml/kg of FFM/min (relative to FFM)
  • Range 15 (sedentary with disease) to 75 (young endurance runner) ml/kg/min
  • Women about 10-20% lower than men
methods of determining vo 2 max
Methods of Determining VO2 max
  • Submaximally
  • Maximally
slide10
GXT
  • Graded Exercise Testing - GXT (incremental increases in workload)
  • General Guidelines
    • measure the subject’s HR and BP and RPE at regular intervals (near the end of each stage [HR, BP, RPE] or every minute [HR])
    • if HR does not reach steady state during the stage extend stage 1 minute
slide11
GXT
  • General Guidelines
    • All testing begins with a 2-3 min warm-up
    • Cool- down at a low intensity for at least 4 minutes - continue measuring HR, BP and RPE
    • increase intensity in .5-2 MET increments
    • closely observe subject for contraindications
submaximal assumptions
Submaximal Assumptions
  • 1. A steady-state HR is obtained for each exercise work rate
  • 2. A maximal HR for a given age is uniform (220-age)
assumptions
Assumptions
  • 3. Mechanical efficiency (ie. VO2 at a given work rate) is the same for everyone.
    • This may not be true and it has been suggested that submaximal exercise testing underestimates VO2max in the untrained and overestimates in the trained
submaximal assumptions1
Submaximal Assumptions
  • 4. There is a linear relationship between HR and Workload
  • 5. HR will vary depending on fitness level between subjects at any given workload
submaximal protocols
Submaximal Protocols
  • Oxygen consumption for any given WL does not vary between subjects
  • The slope of the line is about the same for any two given subjects
  • The rate of increase in O2 consumption with increasing WL does not vary between subjects
submax protocols
Submax Protocols
  • HR does vary between subjects
  • rate of increase in HR depends on fitness level
  • The more fit you are the lower your HR at any given WL
  • An untrained person will reach their HR max at a lower WL vs. a trained person of the same age.
slide22

.

HEART RATE, VO2, AND INCREASING WORK

submaximal protocols1
Submaximal Protocols
  • 1. YMCA - bike
  • 2. Astrand Rhyming – bike
  • 3. ACSM - bike
  • 4. Bruce Protocol - treadmill
  • 5. McCardles Step Test
slide25
YMCA
  • Multi-stage protocol
  • 3-4 consecutive 3 minute stages
  • HR between 110-150 bpm (the HR range at which the relationship between VO2 and WL is most linear)
ymca procedures
YMCA Procedures
  • 1. Adjust seat height (legs nearly straight when extended - 5º bend)
  • 2. Measure pre-exercise BP and HR with subject seated on bike
  • 3. Pedal at 50 rpm (if using a metronome - 100x/minute)
  • 4. Warm-up, zero resistance for 2-3 minute
ymca protocol
YMCA Protocol
  • 5. Stage 1
    • .5 kp for 3 minutes
    • at every stage measure BP at 2.0 min (more often if hypertensive)
    • at every stage measure HR during last half of minutes 2 and 3
    • if HR at 2 and 3 minutes differ by more than 6 bpm extend the stage for 1 min
ymca protocol1
YMCA Protocol
  • 6. Stage 2
    • Workload in this stage and successive stages depends on HR during stage 1 (p 75 guidelines)
  • 7. Continue test until HR recorded at two successive WL are between 110 and 150 bpm (for many this occurs during 2nd and 3rd WL)
ymca protocol2
YMCA Protocol
  • 8. Note that if HR is greater than 110 at end of 1st stage then only one more stage is necessary
  • 9. At completion of test reduce resistance to .5kp and allow subject to pedal for at least 4 minutes or until HR falls below 100 bpm and BP stabilizes.
ymca protocol3
YMCA Protocol
  • 10. The HR measured during the last minute of each stage is plotted against workload.
  • 11. The line generated from the plotted points is extrapolated to the age-predicted HR max
  • 12. A perpendicular line is dropped to the x-axis to estimate the work rate this person would achieve if taken to max.
acsm bike test
ACSM Bike Test
  • 1. 2-3 minute warm-up
  • 2. Take HR twice during each stage (3 minute stages) and RPE/BP once (similar to YMCA)
  • 3. If HRs are greater than 110, steady state should be reached (HRs within 6bpm) before increasing the workload
slide33
ACSM
  • Protocol A B C (kgm/min)
  • Stage 1 150 150 300
  • Stage 2 300 300 600
  • Stage 3 450 600 900
  • Stage 4 600 900 1200
slide34
ACSM
  • Protocol Selection
  • BW Very Active
  • (kg) No Yes
  • <73 A A
  • 74-90 A B
  • >91 B C
    • *very active is defined as aerobic exercise 20 minutes, 3 days/week
slide35
ACSM
  • 5. Terminate test when HR reaches 85% of age-predicted max HR or 70% of HR reserve
  • 6. Recovery at workload equal to the 1st stage or less for at least 4 minutes with HR, BP, and RPE monitored.
slide36
ACSM
  • Plot HRs from last two stages to determine VO2max much like YMCA.
astrand rhyming
Astrand Rhyming
  • Single-stage test (VO2 max is determined using 1 submaximal data point-HR)
  • Duration of test is 6 minutes
astrand rhyming1
Astrand Rhyming
  • 1. Adjust seat height (legs nearly straight when extended - 5º bend)
  • 2. Measure pre-exercise BP and HR with subject seated on bike
  • 3. Pedal at 50 rpm (if using a metronome - 100x/minute)
  • 4. Warm-up, zero resistance for 2-3 minute
astrand rhyming2
Astrand Rhyming
  • 5. Pedal rate is 50 rpm
  • 6. Determine Workload
    • unconditioned males - 300 or 600 kgm/min
    • conditioned males - 600 or 900 kgm/min
    • unconditioned females - 300-450 kgm/min
    • conditioned females - 450 or 600 kgm/min
  • 7. 6 minute test
astrand rhyming3
Astrand Rhyming
  • 8. At end of 2nd minute of pedaling take HR (BP at 1.25-1.5 min)
    • want the HR to be between 125-170bpm
    • if less than 125 increase resistance by 1 kp for men and 1/2 kp for women
    • if greater than 170 bpm decrease resistance by 1 kp
    • continue to monitor HR every minute until HR exceeds 125
astrand rhyming4
Astrand Rhyming
  • 9. At the end of the 5th and 6th minute take HR and average the two values (make sure values are within +6bpm to assure a steady state HR was obtained)
  • 10. BP at 4:30 and 5:30
  • 11. Reduce resistance and cool-down for 4 minutes.
astrand rhyming5
Astrand Rhyming
  • 10. Determine VO2 from nomogram (p. 73 guidelines, p.69 Heyward)
  • 11. Age-correction factor (p. 74 guidelines, p.72 heyward)
  • 12. Convert to relative value
treadmill tests
Treadmill Tests
  • Bruce Protocol
  • Balke
  • Ellestad
  • Others……….
treadmill protocols
Treadmill Protocols
  • Bruce and Ellestad
    • larger increments
    • use on younger and/or more physically active
  • Balke-Ware
    • smaller increments (1MET/stage or lower)
    • use on older, deconditioned, and/or diseased subjects
treadmill protocol
Treadmill Protocol
  • Single-stage (using one data point) even though we may have more than one stage
  • May need to have a long accustomization period and explanation of procedures before beginning
bruce treadmill protocol
Bruce Treadmill Protocol
  • 1. Measure resting BP and HR while standing on the belt of the treadmill
  • 2. Ask subject to straddle the belt while starting treadmill at 1.7 mph and 0% grade
  • 3. Ask subject to begin walking and when comfortable release handrails
  • 4. This is a warm-up and should continue until subject is comfortable
bruce treadmill protocol1
Bruce Treadmill Protocol
  • 5. Stage 1
    • Increase grade to 10%
    • 3 minutes long
    • Measure HR at end of each minute and BP at end of each stage
bruce treadmill protocol2
Bruce Treadmill Protocol
  • 6. The objective is to reach a steady state HR between 115 and 155 bpm (usually occurs during the first 6 minutes of exercise or by the end of the 2nd stage) – Page 98 guidelines
  • 7. Once subject reaches proper HR terminate the test at the end of that stage
bruce treadmill protocol3
Bruce Treadmill Protocol
  • 8. Reduce treadmill speed to 1.7mph and 5% grade and cool-down for 4 minutes.
  • 9. VO2 is estimated from the last minute of a fully completed stage
treadmill protocol1
Treadmill Protocol
  • 10. Calculate VO2 from the gender specific equations
  • Males
    • VO2=SMVO2 [(HRmax-61)/(HRSM-61)]
  • Females
    • VO2=SMVO2[(HRmax-72)/(HRSM-72)]
    • SMVO2 = submaximal VO2 from table or ACSM equations
    • HRSM = submax HR from test
modified bruce protocol
Modified Bruce Protocol
  • Start at 1.7 mph, 0% grade or at 1.7 mph and 5% grade (used on diseased and elderly populations)
treadmill protocol2
Treadmill Protocol
  • Protocols should be individualized
  • Test time should ideally be 8-12min
  • Increments of 10-15 W/min or 1-3%/min grade can be used for the elderly
mccardle s step test
McCardle’s Step Test
  • Bench ht. = 41.25 cm
  • Step Rate = 24 step/min (metronome = 96) for men and 22 step/min (metronome=88) for women
  • 3 minutes of stepping
  • Record HR from the first 15seconds after the stepping has stopped
mccardle
McCardle
  • Men
    • VO2 = 111.33 - (0.42 x HRrec)
  • Women
    • VO2 = 65.81 - (0.1847 x HRrec)
    • value is ml/kg/min
maximal testing
Maximal Testing
  • Assumption: The subject was highly motivated and gave a maximal effort.
max testing
Max Testing
  • Laboratory Tests
  • 1. Open Circuit Indirect Calorimetry
  • 2. Cycle
  • 3. Treadmill (Bruce)
maximal protocols
Maximal Protocols
  • Field Tests
  • 4. 12 minute run
  • 5. 1.5 mile run
  • 6. Rockport Walking Test
measuring energy costs of exercise
Measuring Energy Costs of Exercise
  • Direct calorimetry—measures the body's heat production to calculate energy expenditure.
  • Indirect calorimetry—calculates energy expenditure from the respiratory exchange ratio (RER) of CO2 and O2.
respiratory exchange ratio
Respiratory Exchange Ratio
  • The ratio between CO2 released (VCO2) and oxygen consumed (VO2)
  • RER = VCO2/VO2
  • The RER value at rest is usually 0.78 to 0.80
slide62
RER
  • Value ranges from .7-1.0
  • 0.7 mainly uses fats as an energy source
  • 1.0 mainly uses carbohydrates as an energy source
  • Can exceed 1.0 during heavy non-steady state, maximal exercise, or when nervous due to hyperventilation (increased CO2)
kcals
KCALS
  • (RER + 4) x (Liters of O2 consumed per minute) = kcal/minute
  • For example:
    • RER determined from gas analysis = .75
    • 4 + .75 = 4.75
    • L of O2 per minute = 3 liters
    • 4.75 x 3 = 14.25 kcal/min
    • If exercised for 30 minutes = 427.5 kcals
cycle to max
Cycle to Max
  • 15 W/min protocol
  • VO2males =10.51 (power in W) + 6.35 (BW in kg) - 10.49 (age in y) + 519.3
  • VO2females =9.39 (power in W) + 7.7 (BW in kg) - 5.88 (age in y) + 136.7
  • values are in ml/min - divide by BW in kg
treadmill to max bruce
Treadmill to Max (Bruce)
  • VO2 = 14.8 - 1.379 (time in min) + 0.451 (time2) - 0.012 (time3)
  • While holding handrail
  • VO2 = 2.282 (time in min) + 8.545
population specific equations
Population-specific Equations
  • P. 61 Heyward
  • Active vs. Sedentary, Gender specific, Cardiac patients
12 minute run1
12 minute run
  • The further you can run in 12 minutes the higher your VO2max
1 5 mile run 1 mile walk
1.5 Mile Run/1 Mile Walk
  • The faster you can run 1.5 miles or walk 1 mile the higher your VO2max
field tests
Field Tests
  • 12 min run
    • VO2 = 3.126 (meters in 12 min) - 11.3
  • 1.5 mile run
    • VO2 = 3.5 + 483/(time in minutes)
  • Rockport Walking Test (1 mile walk)
    • VO2 = 132.853 - 0.1692 (BW in kg) - 0.3877 (age in y) + 6.315 (gender) - 3.2649 (time in min) - 0.1565 (HR)
    • 0 for female; 1 for male; HR at end of walk
normal responses to gxt
Normal Responses to GXT
  • 1. Systolic BP increases in direct proportion to increasing WL
  • 2. HR increases linearly with WL
  • 3. Diastolic BP changes very little
  • 4. Shortened QT Interval
  • 5. Reduced R-wave amplitude
  • 6. Positive upslope of ST segment
abnormal responses to gxt
Abnormal responses to GXT
  • 1. ST segment depression
  • 2. Increased R-wave amplitude
  • 3. V-tach
  • 4. Multiform PVC’s
  • 5. Failure of HR to rise with WL
  • 6. Failure of systolic to rise
  • 7. Systolic and diastolic greater than 250 or 120
test termination
Test Termination
  • 1. Have reached a pre-determined endpoint
  • Absolute
  • 1. Suspicion of myocardial infarction
  • 2. Moderate to severe angina
  • 3. Drop in Systolic BP with increasing Workload (>20)
absolute
Absolute
  • 4. Arrhythmias
  • 5. Pale or cold and clammy skin
  • 6. Severe shortness of breath
  • 7. Dizzy, blurred vision, or confusion
  • 8. Patient requests stop
  • 9. V-tach or multiform PVC’s
  • 10. ST segment depression
absolute1
Absolute
  • 11. Excessive rise in BP (systolic >250; diastolic >120)
  • 12. Failure of HR to increase
relative
Relative
  • 1. ECG changes from baseline
  • 2. Chest pain that is increasing
  • 3. Wheezing
  • 4. Leg cramps
  • 5. High Systolic/Diastolic
  • 6. Less serious arrhythmias
  • 7. Less severe shortness of breath
advantages of submaximal testing
Advantages of Submaximal Testing
  • 1. Safer
  • 2. Controlled pace (motivation not a factor)
  • 3. Not population specific (no pacing advantage)
  • 4. Quick assessment
  • 5. Cost effective
advantages of submaximal testing1
Advantages of Submaximal Testing
  • 6. Don’t need highly trained personnel
  • 7. Can do mass testing
  • 8. No physician supervision required (if symptom and disease free)
disadvantages of submaximal testing
Disadvantages of Submaximal Testing
  • 1. VO2 max is not directly measured (error rate of 10-20%)
  • 2. Don’t get a measure of true maximal HR
    • estimates of max HR using 220-age can vary by +15 bpm for individuals of the same age
advantages and disadvantages of a maximal test
Advantages and Disadvantages of a Maximal Test
  • Advantages
  • 1. More accurate
  • Disadvantages
  • 1. Motivation is a factor
  • 2. More risk involved
  • 3. Time
  • 4. Cost of equipment (if using metabolic cart)
walking running vs cycling stepping
Walking/Running vs. Cycling/Stepping
  • Walking/Running are the most natural forms of locomotion (most Americans are unaccustomed to cycling
  • In general, subjects reach higher VO2max values during treadmill tests
  • Treadmill are more expensive than cycles
  • Treadmill is less portable
walking running vs cycling stepping1
Walking/Running vs. Cycling/Stepping
  • Body weight has a much smaller effect on cycle ergometry versus treadmills
  • Treadmill more dangerous (greater risk of a fall
  • Measurement of HR is more difficult on a treadmill and while stepping