Chapter 4: Cardiorespiratory Fitness

I. Maximum Oxygen uptake defined as the greatest rate at which oxygen can be consumed during exercise or the maximal rate at which oxygen can be taken up, distributed, and used by the body during physical activity.

II. Contributions to max VO2

a. respiratory system

b. CV system

c. Musculoskeletal system

III. Determination of true max

a. oxygen consumption plateaus during the last minutes of a graded exercise test (defined as a rise of less than 2 ml/kg/min between the final test stages

b. The respiratory exchange ratio increases to 1.15 or higher

c. Subjects HR increases to within 10 beats of age predicted max HR

d. Blood lactate levels > 8 mmol/liter

IV. Laboratory measurement of max VO2 is expensive, timeconsuming, requires highly trained personnel, potentially higher risks, and is not practical in most situations.  Various formulas and tests have been developed as substitutes.

a. nonexercise test VO2 max predictions

b. field tests of CR endurance

c. submaximal lab tests

d. maximal lab tests

V. Before these tests are conducted the preliminary considerations, such as medical/health screening questionnaire, consent form, and if high risk as physical exam by a physician, a treadmill test and possibly a blood lipid analysis.

VI. An order should be followed for a testing battery. 

a. It should take about 1 hour. 

b. Precise instructions are given to the participants before they come for testing

c. Should dress in the proper exercise attire, and bring a swim suit if necessary

d. Avoid eating or drinking for 3 hours prior to the test.

e. Avoid exercising on the day of the test

f. Try to get a good night’s sleep

g. Bring the medical/health questionnaire

h. If blood is to be analyzed avoid alcohol and vigorous exercise for 24 hour prior to the test, and a 12 hour fast; diabetics should be allowed to keep their dietary habits and injections of insulin as regular as possible, and patients should continue their medication regimen on their usual schedulae so that the exercise test responses will be consistent with responses expected during exercise training.

i. Testing session should begin with quiet, resting tests (HR, blood pressure, blood drawing, all after a 5 minute rest)

j. Body composition measures

k. Graded exercise testing for cardiorespiratory endurance

l. Musculoskeletal tests;  if done before the CR tests the HR & BP could be elevated

m. Immediate feedback and counseling should follow the testing. 

VI. Examples:  YMCA

a. standing height

b. weight

c. resting HR and BP

d. skinfold tests

e. submaximal cycle test for CR endurance; or 3 minute step test for mass testing

f. sit and reach test

g. Bench press test (35 # for women; 80 pounds for men at a rate of 30 times per minute for muscular endurance and strength)

h. Timed (1 minute) situps for abdominal muscular endurance or abdominal curlups

VII. Examples: Canadian

n. resting HR

o. BP

p. standing height

q. weight

r. waist girth

s. skinfolds (triceps, biceps, subscapular, iliac crest, medial calf)

t. Canadian aerobic fitness step test

u. Grip strength

v. Pushups

w. Trunk forward flexion

x. Partial curlups

y. Vertical jump

VIII. Blood pressure measurement

For best results

a. mercury stand sphygnomanometer, a recently calibrated aneroid manometer, or validated electronic device.

b. 2 or more readings should be taken 30-60seconds apart, and averaged; if differ by more than 5 mmHg, and additional reading is taken

c. take measurement in a quiet room with temperature approx. 70-74 deg F, or 21-23 deg. C

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

e. with older people, because of potential arterial obstructions, it is best to take readings on both arms.  If the pressures differ by more than 10 mmHg obtain simultaneous readings in the two arms and thereafter use the arm with the high pressure.

f. Use the proper size cuff.  The rubber bladder should encircle 80% of the arm.  If the person’s arm is large the adult normal size cuff will be too small making the reading larger than it actually should be

g. Between determinations allow 30 seconds for normal circulation to return to the arm.

h. Subject should be comfortably seated with the arm straight, palm up, and the whole forearm supported at heart level on a smooth surface.

i. Anxiety, emotional turmoil, food in stomach, bladder distension, climate variation, exertion and pain all may influence the BP and should be avoided or controlled.  Smoking or ingested caffeine should be avoided for at least 30-60 minutes prior to measurement.  Note the time when the person took any medication for BP and the name of the medication. 

j. For procedures see the lab 1

IX.  Exercise HR – ECG

X.  Field tests for CR fitness

A. Running Endurance tests

1 mile run prediction test

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

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

B. 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

C. 1.5 mile run for college students

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

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

D. 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

XI. Table 4.4 estimation of VO2 max from average running speed

XII.  SUBMAXIMAL LABORATORY TESTS

A. Three assumptions for submax exercise testing

1. A linear relationship exists between heart rate, oxygen uptake and workload

2. The maximum heart rate at a given age is uniform

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

B. These assumptions are not entirely accurate and can result in 10-20% error.

1. Table 4.10 shows that in most submaximal tests, HRs at submaximal workloads are plotted, then extrapolated to an estimated maximum heart rate level, 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 of ±12 beats

b. 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 given workload) and underestimate the untrained.

3. Why test using submax testing?

a. larger numbers can be tested quickly

b. not as much skill needed to administer the test

c. not as much equipment required

d. the subject tested does not have to perform an all out effort

e. max testing requires a high level of motivation to get to max

f. submax testing can give an adequate assessment of fitness status without risk, expense, and hard effort.