assesment cardiorespiratory fitness

8/22/2019 ASSESMENT Cardiorespiratory Fitness

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Cardiorespiratory Fitness


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Maximum Oxygen Uptake(VO2max)

Definition:

Maximum Oxygen uptake defined as thegreatest rate at which oxygen can beconsumed during exercise or the maximalrate at which oxygen can be taken up,distributed, and used by the body during

physical activity.


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Contributions to max VO2

a. respiratory system

b. CV system

c. Musculoskeletal system


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Determination of true maxCriteria

1. oxygen consumption plateaus during thelast minutes of a graded exercise test(defined as a rise of less than 2 ml/kg/min

between the final test stages2. The respiratory exchange ratio increases

to 1.15 or higher

3. Subjects HR increases to within 10 beatsof age predicted max HR

4. Blood lactate levels > 8 mmol/liter


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Measurement of max VO2

1. Laboratory measurement (Graded Exercise Test/ GXT)

i. maximal lab tests

expensive,

time consuming

requires highly trained personnel potentially higher risks

not practical in most situations.

ii. submaximal lab tests

2. nonexercise test VO2 max predictions

3. field tests of CR endurance


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Measurement of max VO2 (contd)

Before VO2max measurement areconducted the preliminary considerations,such as

medical/health screening questionnaire,

consent form,

physical exam by a physician if high risk

a treadmill test

possibly a blood lipid analysis.


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Measurement of max VO2 (contd)Graded Exercise Test (GXT)

Purposes for GXT1. assess the safety in terms of starting or changing an exercise program2. aid in the diagnosis of heart disease3. prescribing an appropriate exercise program4. to follow the progress of known coronary or pulmonary disease5. to determine effectiveness of medical or surgical procedures involving medication

6. to develop a rapport with an indiv.7. to assess the CV or Pulmonary capacity of both the apparently healthy and the

diseased8. To determine when to interfere

put in a new valve

What do GXT's do

1. Yield sig. data on the status of heart and lung functional capacities2. detects myocardial ischemia - not CAD3. Yield the cardiorespiratory capacities for exercise prescription purpose

Purposes of GXT's1. Functional2. diagnostic3. Prognostic


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Factors that determine the depth of GXT scan1. age2. health status3. type of test ( max )4. exercise plan (vigorous or sedentary)

5. Submaximal or maximal Test

Importance of screening prior to exercise testing1. safety2. choosing appropriate exercise testing

3. identification needs for more comprehensive medical evaluations4. prescribing appropriate exercise programs

nature of the exercise programs


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Three categories to undergo GXT1. apparently healthy2. high risk

symptoms suggest CV, Pumonary or metabolic prob's; or al least one majorcoronary risk factor

Major Coronary risk factors

1. High BP - 145 / 952. Total Cholesterol / HDL's > 5.03. Cig. smoking4. Abnormal resting ECG

is indirect evidence of an old myocardial infarct, l-ventricular hypertrophy,ischemia, conduction defects, or disrhythmias

5. Family history of coronary or other atherosclerosis prior to age 50

6. Diabetes Mellitus

3. Individual's with known diseases Metabolic Diseases

1. Diabetes2. renal disease3. thyroid disorder

4. liver disease5. other smaller diseases


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Classify individuals1. Give a medical questionnaire2. Then put them in one of the above three categories

Guidelines for GXT

1. Apparently Healthy no major coronary risk factorsi. If < age 45

Not compulsory to exercise test prior to beginning an exerciseprogram

ii. if 45 or older give a max exercise test before beginning or changing the

exercise program

all max exercise tests after age 35 should be done with a physicianpresent

a sub max test at any age will not require a physician it is valuable to giving a safe exercise prescription


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2. High risk1. GXT max is desirable at any age

esp. with symptoms physician should be there

2. without symptoms and less than 35

no physician necessary3. Sub-max tests little diagnostic value lead to determination of heart disease functional test tests fitness

4. Symptomatic at any age

need a physician supervised max test

3. Diseased Need a physician supervised max test Purpose

1. to determine the safety of the exercise

2. to determine functional capacity


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Complications and potential risks of GXT's1. Extremely low risk of morbidity both max and sub-max

deaths are not related to severity deaths are 1 / 10,000

2. the complication rate is 8 / 10,000

3. ventricle Arrhythmia or myocardial Infarction (MI) = 4 / 10,000

The risks appear acceptable each case is evaluated separately as to the benefits vs. the risk (

exp. with the old and diseased )

The PAR-Q is used as a bare minimum will identify those to whom exercise may be harmful contains 6 questions if answer yes, then should not exercise until cleared by a

physician


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Depth of the evaluation

in addition to the others ( age, health status,type of test, and exercise plan )

Other complications evaluated prior toexercise testing

(1) medical history

is the most important(2) physical exam.

3) lab tests


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Conditions for a GXT1. Continuous or non-continuous

children use non-cont a ramp protocol is a continuous one

2. Single load or multi-staged3. supine or upright

4. modality5. max or a sub-max6. nature of recovery

cool down(1) not needed with cardiac patients if looking at recovery(2) if not enough time (over 10 min.) have them lie down and elevate the feet

7. Type of protocol

a. diseased statusb. activity statusc. age

more likely to get a false positive than a true positive myocardium irritability increases with age

8. orthopedic considerations


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GXT preparations1. Patient preparation

food, clothing, etc.2. Complete medical history and any lab tests3. Consider the indications and the contraindications to testing

recent MI is a definite contraindication recent illness is also

will get a false positive4. consideration of the factors leading to a false positive or negative

sub-max tests => false negatives because of1. did not get high enough intensity

2. more likely in the females (big breasted ones esp., and the old)5. consideration of drug effects and electrolyte imbalance are they on drugs diuretics effect the electrolyte imbalance

6. obtain the informed consent


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Subject preparation1. Avoid strenuous activity on the day of the test, esp. 2-4 hr before

if testing athletes, have them rest the day before2. have an overnight fast, or four hours past a heavy meal or 2 hours

past a light meal

3. avoid caffeine 2-4 hrs before they increase the PVC's and HR

4. no alcohol or cigs 2-4 hrs before, esp. just before alcohol can both increase and decrease HR

5. free of any illness or discomfort

6. dressed comfortable with light shoes7. 68-74 deg. F., with a 40 - 60 % humidity8. rest comfortable in a supine position 10 min. prior


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Informed consent (would not hold up in court)1. absolute necessity- though not universally recognized2. ACSM - states they should sign prior to exercise3. the exact value of the medical viewpoint is not clear

people cannot waive their right to sue4. PURPOSE - to make certain the participant is aware of the risk

if a subject asks excessive questions, this person is likely to sue ifsomething goes wrong

Specifics of an informed consent1. Immediately prior to exercise, the participant must receive2. Should contain

a) explanation of the procedures, purpose, risks, discomfort, and benefitsb) offer to fully answer any questionsc) both the person and the test administrator should sign should sign

if a minor, then both parents and the minor should signd) a brief demonstration of the test procedures


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Graded Exercise Test (GXT)Maximal Exercise Test

Maximal Tests should Involve large muscle groups Allow for measurable and reproducible workload Be tolerated by a variety of people Mechanical efficiency should be as uniform as possible in the population study

people should be equally efficient

Difficulties in Maximal Test1. Motivation

i. subjectii. administrator

relates to experience2. Increased risk of bringing on a cardiac abnormality

especially in the middle aged3. Values depend on the accurate calibration of the ergometer and the measuring

device should allow for constant efficiency

4. All subjects should be able to tolerate a similar accumulation of anaerobic metabolites(need to keep anaerob. part constant)

Especially in the bike, as it requires more anaerobic capacity


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Graded Exercise Test (GXT)Maximal Exercise Test Protocols

1. Typesi. Naughton - good for the average person, has steady increasesii. Ellestat - bigger jumpsiii. Catisiv. Balke - he is the father of treadmill protocols

3-4 MPH walking

v. Bruce - is a standard (considered useless by many)STAGE MPH % GRADE MINUTES / STAGE METS

1 1.7 10 3 42 2.5 12 " 6-73 3.4 14 " 8-94 4.2 16 " 15-16

5 5.0 18 " 216 5.5 20 "7 6.0 22 "

NEED TO MEMORIZE STAGES


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Graded Exercise Test (GXT)Maximal Exercise Test Protocols

2. Reasons to stop the test

i. Absolute

a) visual disturbances

b) confusion

c) Three or more premature ventricularcontractions

d) malfunctioning equipment

ii. Relative

a) Less serious symptoms dizziness

leg pain

b) SBP increases less than 20 mm / Hg


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Graded Exercise Test (GXT)SUBMAXIMAL LAB TESTS (contd)

Why test using submax testing?1. larger numbers can be tested quickly2. not as much skill needed to administer the test3. not as much equipment required4. the subject tested does not have to perform an all out effort5. max testing requires a high level of motivation to get to max6. submax testing can give an adequate assessment of fitness status

without risk, expense, and hard effort.7. to avoid potential risk of maximal testing

safer (by 3 times) for cardiac emergencies difficult to arrange for medical coverage

8. require no specific skill9. do not require the subject to stress till max

some measure VO2, while most measure HR

Sub - Max tests should not be used for1. Research

2. comparisons between individuals


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Graded Exercise Test (GXT)SUBMAXIMAL LAB TESTS

Three assumptions for submax exercise testing:1. A linear relationship exists between heart rate, oxygen uptake and workload

throughout the entire range this depends on the steady increasing CO and A-VO2 difference. the deviation from this in healthy young adults is small in the older, the dev. is more as the SV may not be sustained, causing too

much increase in HRi. if intensity too low, SV may not max and the HR may fluxateii. if too high, VO2 will plateau, HR will continue to increase, and the VO2 will

be underestimated because the HR will be disproportionately high

2. The maximum heart rate at a given age is uniform. That an individuals HR varies little from the mean

220 - age has a std.dev. of +/- 12 beats / min.

3. the mechanical efficiency (oxygen uptake at a given workload) is the same foreveryone.

it actually varies more on the bike than on the t-mill solution:

instead of testing them right away on the exercise, why not let them come

into the program and let them get used to the equipment, then test them.This may eliminate much of the mech. eff. difference


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These assumptions are not entirely accurate and canresult in 10-20% error due to1. in most submaximal tests, HRs at submaximal workloads are

plotted, then extrapolated to an estimated maximum heart ratelevel, and then further extrapolated to an average oxygen

consumption.2. These extrapolations can result in substantial error.a. max HR using the equation 220-age varies considerably among

individuals of the same age. One SD of12 beatsb. oxygen uptake at the same workload can vary 15% among different

people. Some are more efficient than others.c. VO2max estimates from submax tests tend to overestimate those

who are highly trained (they respond with a low HR at a givenworkload) and underestimate the untrained.


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Choice of Equipment1. Treadmill

There are some tests available, but due to cost restraints, this is not the methodof choice.

Normally used for maximal tests2. Bicycle

1. Cost Much less $ 10 bikes = 1 t-mill

2. Less space3. t-mill is seen as ominous4. bike has a measurable - reproducible workload5. Used for assessing work capacity

except for bicyclers, it is hard to test for maximal values on the bike

6. Mechanical efficiency is independent of weight except in the very obese

7. Efficiency varies with RPM (for any given workload) unless you have a RPMindependent bike

8. 50 RPM is the optimal efficiency for sub-max tests at > 200 watts, RPM need to progressively increase past 60 RPM ( 90 RPM

is the optimal pedaling rate for elite cyclists)

if the test requires a change if the wattage, one needs to also change therpm to keep the efficiency from dropping too much


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ACSM sub max test HRmax = 220 - age has some variance

some people may stop at 70 or even 100 % HRmax

The ACSM test has different endpoints1. 85 % of HR max2. pre determined exercise intensity3. achieve a certain RPE

VO2 max is an unreliable measure

Not is good for diagnosis, as need to go a highintensity

used best for intraindividual differences


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ACSM sub max test

measured in ml/min and is non-weight bearing bigger (muscled or resistant trained) people have an advantage

may therefore overestimate their VO2max Considerations for the protocol

1. weight

2. activity status questionnaire works for both the test and the prescription Monitor HR during the test

the last 15 sec of each.stage for 2-3 stages Test termination

70 %HRmax is okay for older population (35-40 yrs old), but may not be a highenough intensity for younger people

Calculation of VO21. use the axis derivation2. or use 2 KGM + 300

used for non-weight bearing activities that only have one point ex: if the max is 200 watts, then 200 W = 1200 kgm.,

2*(1200) + 300 = 2700 ml/min

* read for the cycle max protocol


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Legal and procedural considerations1. Standard of care

The AMA, American Heart Assoc.,the ACSM, the American PTassoc. all publish standards forprofessional standards of care

should be familiar with all of them

2. Providing a safe test what constitutes a safe test for the participant

3. Legal risks associated with tests what risks from the test are for the participant


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What constitutes Liability1. Negligence

i. failure to conform ones conduct to a generally accepted std. of dutyii. failure to give due care to protect the patient

if you are supposed to do soiii. the failure to protect proximally caused the injury

in general(1) must have to protect(2) must have the responsibility to protect(3) prove proximal cause from the failure to protect

2. Other parameters (if omitted)i. monitoring ECG, HR, BP, RPE, etc.ii. pre-screening (risk factor ass.) or medical screeningiii. with more education, are held more responsibility.iv. still held accountable for std. of care if have just a little knowledgev. cannot practice medicine without a license (or will be in violation of a

civil and a criminal law) cannot diagnose and prescribe ECG's


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To minimize risks1. Exercise due care consistent with common professional

standards not avail for medical exer. testing

2. Execute a consent form

it is an assumption of some of the risks by the subject

Conducting an Informed Consent Subject must be legally capable of giving consent (adult) must know and fully understand risks consenting to

must know all facts and related dangers in order to make aninformed decision must give the consent voluntarily, under no duress


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Further considerations Be aware of organizations that publish standards Ask questions regarding activity habits know of local medical practices and national standard's add knowledge of risks to consent form (adapt it to population) have a legal council and a medical director MUST have liability insurance If you suggest your program is a preventative program, then it is a

medical program See the state statutes on informed consent Have a physician answer questions from participants obtain consent by audio/video tape keep copies of records (questions and responses) Document the emergency procedures Inspect the physical site (w/ written records) Institute people how to use equipment keep records on personal certifications evaluate employees periodically, check out references


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Field tests for CR fitness

A. Running Endurance tests

1. 1 mile run prediction test

VO2 max (ml/kg/min) = (-8.41 X MRT) + (0.34 X MRT2) + (0.21 X ageX sex) (0.84 X BMI) + 108.94

Sex = 0 for females, 1 for males; BMI = body mass index in kg/m2

Example: 15 year old male ran the mile in 6.5 minutes, a BMI of 21

VO2max = (-8.41 X 6.5) +(0.34 X 6.52) + (0.21 X 15 X 1) (0.84 X 21) + 108.94= 54.2 ml/kg/min


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2. 1.5 mile run for college students

VO2max = 88.02 + (3.716 X gender) (0.1656 X kg) (2.767 Xtime)

Gender = 0 for females; 1 for males; time = total time in minutes

Example: a 70 kg male ran 1.5 miles in 9 minutes

VO2 max = (88.02)+(3.716 X 1) (0.1656 X 70) (2.767 X 9)= 55.3 ml/kg/min


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Estimation of VO2 max fromaverage running speed


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An order should be followed for atesting battery.

1. It should take about 1 hour.2. Precise instructions are given to the participants before

they come for testing3. Should dress in the proper exercise attire, and bring a

swim suit if necessary4. Avoid eating or drinking for 3 hours prior to the test.5. Avoid exercising on the day of the test6. Try to get a good nights sleep7. Bring the medical/health questionnaire


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An order should be followed for atesting battery.

8. If blood is to be analyzed avoid alcohol and vigorous exercise for24 hour prior to the test, and a 12 hour fast; diabetics should beallowed to keep their dietary habits and injections of insulin asregular as possible, and patients should continue their medicationregimen on their usual schedule so that the exercise testresponses will be consistent with responses expected during

exercise training.9. Testing session should begin with quiet, resting tests (HR, bloodpressure, blood drawing, all after a 5 minute rest)

10. Body composition measures11. Graded exercise testing for cardiorespiratory endurance12. Musculoskeletal tests; if done before the CR tests the HR & BP

could be elevated13. Immediate feedback and counseling should follow the testing.


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Examples: YMCA

1. standing height2. weight3. resting HR and BP4. skinfold tests

5. submaximal cycle test for CR endurance; or 3 minutestep test for mass testing6. sit and reach test7. Bench press test (35 # for women; 80 pounds for men

at a rate of 30 times per minute for muscular endurance

and strength)8. Timed (1 minute) situps for abdominal muscular

endurance or abdominal curlups


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Examples: Canadian

1. resting HR2. BP3. standing height4. weight5. waist girth

6. skinfolds (triceps, biceps, subscapular, iliac crest, medial calf)7. Canadian aerobic fitness step test8. Grip strength9. Pushups10.Trunk forward flexion

11.Partial curlups12.Vertical jump


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Blood pressure measurement

For best results1. mercury stand sphygnomanometer, a recently calibrated

aneroid manometer, or validated electronic device.2. 2 or more readings should be taken 30-60seconds apart,

and averaged; if differ by more than 5 mmHg, andadditional reading is taken

3. take measurement in a quiet room with temperatureapprox. 70-74 deg F, or 21-23 deg. C

4. having upper arm bare makes it easier to adject the cuff

5. with older people, because of potential arterialobstructions, it is best to take readings on both arms. Ifthe pressures differ by more than 10 mmHg obtainsimultaneous readings in the two arms and thereafteruse the arm with the high pressure.


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6. Use the proper size cuff. The rubber bladder shouldencircle 80% of the arm. If the persons arm is largethe adult normal size cuff will be too small making thereading larger than it actually should be

7. Between determinations allow 30 seconds for normal

circulation to return to the arm.8. Subject should be comfortably seated with the arm

straight, palm up, and the whole forearm supported atheart level on a smooth surface.

9. Anxiety, emotional turmoil, food in stomach, bladder

distension, climate variation, exertion and pain all mayinfluence the BP and should be avoided orcontrolled. Smoking or ingested caffeine should beavoided for at least 30-60 minutes prior tomeasurement. Note the time when the person took

any medication for BP and the name of themedication.


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assesment cardiorespiratory fitness

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