Assessment of Cardiorespiratory Fitness Heart Rates and Blood Pressures

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Assessment of Cardiorespiratory FitnessHeart
Rates and Blood Pressures

• KNR 240
• Fall 2004

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Cardio-respiratory Endurance

• The ability of the body to perform prolonged,
  large muscle, dynamic exercise at
  moderate-to-high levels of intensity
• This is the most important health related
  component of physical fitness.
• A healthy heart is essential to high levels of
  fitness and wellness, as well as to a long and
  healthy life.
• CRE training results in a general improvement in
  the ability to perform aerobic exercise.

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Aerobic and Anaerobic

• Aerobic means with air, using oxygen. The
  term aerobic relates to the energy processes that
  occur in the presence of adequate oxygen.
• Aerobic Fitness is the ability of the heart and
  lungs to provide the oxygen needs of the body
  (muscular system) over a sustained period of
  time.
• Aerobic Fitness may be limited by
• The ability of the lungs to intake O2 and
  transport to the blood
• The ability of the heart to pump oxygenated blood
  to the tissues, the ability of the blood vessels
  to carry the blood, or the ability of the blood
  to completely saturate with oxygen.
• The ability of the muscles to extract oxygen and
  to utilize it.
• Anaerobic refers to an inadequate supply of
  oxygen to meet the demands of physical work the
  body starts accumulating lactic acid, which is
  unable to reduce without adequate oxygen. In
  other words, because there is not enough O2
  present, pyruvate is not allowed to enter into
  Krebs cycle in the cells mitochondria. Due to
  the lack of ample O2, pyruvate converts to Lactic
  acid, and accumulates in the cell.
• Anaerobic threshold refers to the point when
  oxygen availability is not sufficient to meet the
  demands of the workload. The AT is the point at
  which blood lactate concentrations start to rise
  above resting values.

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Oxygen Consumption

• The most accepted index of work capacity is
  maximal oxygen consumption (VO2max). (V
  volume of oxygen used per minute, O2oxygen,
  and maxmaximal exercise conditions).
• VO2max represents the maximal rate of delivery of
  oxygen from the inspired air to the working
  tissues (skeletal muscle). In other words,
  VO2max is 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.
• Remember, Uptake, Distribution, and
  Utilization.
• Physiologically, VO2max is the product of maximal
  cardiac output and maximal (a-v O2) difference.
  This is the amount of O2 extracted from the
  blood.
• Exercise training can significantly improve the
  oxygen transport system and increase VO2 max by
  increasing both the maximal cardiac output and
  the maximal (a-v O2) difference.
• These improvements are one or a combination of
  improvements in the systems of respiration,
  cardiac function, central circulation, peripheral
  circulation, and skeletal muscle metabolism.
• The extent of improvement is determined, in part,
  by the net training work rate performed, and
  thus, depends on the frequency, intensity, and
  duration of each exercise session. The initial
  level of fitness also dictates the amount of
  fitness improvements (The lower the level of
  initial fitness, the greater possible gains.)

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MEASUREMENT OF VO2MAX

• The measurement of max VO2 is a measurement of
  aerobic or cardio-respiratory fitness.
• Direct measurement of oxygen uptake during max
  exercise is considered the best measure of heart
  and lung endurance.
• However, direct laboratory measurement is
  expensive and time consuming, requires highly
  trained personnel, and therefore is not practical
  for most testing situations.

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MEASUREMENT OF VO2MAX

• Therefore, various formulas and tests have been
  developed as substitutes.
• They include
• Non-exercise test VO2max prediction equations
• Field tests of cardio-respiratory endurance
• Sub-maximal laboratory tests
• Maximal laboratory tests.

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Blood Pressure

• BP is the force of blood against the walls of the
  arteries and veins created by the heart as it
  pumps blood to every part of the body.
• Go to http//www.mayoclinic.com/invoke.cfm?object
  idAF528CAA-72A4-4A5A-B65D37511AE58FE2 for new BP
  classifications.
• When taking a BP, one needs a sphygmomanometer
  and a stethoscope.
• A sphygmomanometer is an inflatable compression
  bag enclosed in an unyielding covering called the
  cuff, plus an inflating bulb, a manometer from
  which the pressure is read, and a controlled
  exhaust valve to deflate the system.
• The stethoscope is made of rubber tubing attached
  to a device that amplifies the sound of blood
  passing through the vessels.
• 4. Refer to p. 81-83 for step-by-step
  instructions on blood pressure taking.

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Heart Rate

• Heart rate refers to the number of times the
  heart contracts in 1 min.
• True resting heart rate should be taken upon
  awakening, and averaged from measurements taken
  on at least 3 separate mornings.
• Sites of palpation best determined during rest
  at the radial artery. During exercise, it is
  easier to feel the carotid artery, but remember
  to use caution!!
• Resting heart rate can be affected by
  medications, level of conditioning, stress,
  season of the year, gender, and smoking.
• See Appendix A, Table 21 for norms
• Max heart rate is the maximum number of times per
  minute the heart could beat.
• Estimated max beats equation is 220-age.
• Max heart rate can be affected by medications.
• Polar Heart rate monitors are great for measuring
  exercise heart rate.

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Assessment of VO2 max

• Houston Non-exercise Test Prediction of VO2
• Developed by the University of Houston to
  estimate or predict VO2 based on age, physical
  activity status, and BMI or BF.
• It is felt that the BF equation is slightly more
  accurate.
• Refer to handout and pp. 85-86 for instructions.

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Assessment of VO2 max

• Field Tests of CRE
• 1-mile run
• 1.5 mile run
• 1-mile walk
• These are practical, inexpensive, less time
  consuming than laboratory tests, are easy to
  administer for large groups, and quite accurate
  when properly administered.
• Refer to pp. 86-89 text, or ACSM pp. 71 and 307
  for procedures and equations to determine VO2.
• VO2 max norms are found on p. 697, Table 24.

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Assessment of VO2 max

• Sub-maximal Laboratory Tests
• Less risky, less expensive, and requires less
  motivation than maximal stress tests.
• Makes 3 assumptions
• A linear relationship exists between heart rate,
  oxygen uptake, and workload.
• That the maximum heart rate at a given age is
  uniform.
• That the mechanical efficiency (oxygen uptake at
  a given workload) is the same for everyone.
• The reasoning underlying sub-maximal lab tests is
  that the person with the higher VO2 is able to
  accomplish a given amount of exercise with less
  effort (or more exercise at a particular heart
  rate).

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Assessment of VO2 max

• Sub-maximal Laboratory Tests
• Oxygen uptake at any given workload can vary by
  15 among different people. In other words,
  people vary in the amount of oxygen they require
  to perform a certain exercise work load.
• Some people are more efficient than others, and
  thus the average O2 consumption associated with a
  given workload may differ significantly from one
  person to another.
• Sub-max stress tests tend to overestimate VO2 for
  those who are highly trained, and underestimate
  VO2 for the untrained (those with a high heart
  rate for a given workload).

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Assessment of VO2 max

• Sub-maximal Laboratory Tests
• Step tests
• 1) Modified Canadian Aerobic Fitness Test
• 2) YMCA 3-minute step test
• 3) Queens College Step Test
• Treadmill tests
• 1)Typical cut-off point is 85 predicted max HR
• 2) See p. 94 text
• Bike tests
• YMCA (p. 96 text, p. 75 ACSM)
• Astrand (p. 72 ACSM)

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Assessment of VO2 max

• Maximal Laboratory Testing
• Treadmill
• Bruce-most popular, followed by the Balke. See
  Table 4.8, p. 100 for equations to estimate VO2
  from these tests.
• Naughton-used for cardiac patients.
• Arizona State Univ. test for college students-see
  p. 101.
• See p. 98 ACSM for VO2s associated with
  different stages of various protocols, also see
  Box 4.4 p. 101 text for ACSM walking and jogging
  VO2 formulas.
• Cycle
• Astrand
• Storer-Davis
• Wingate Anaerobic
• Refer to p. 102

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Termination of Maximal GXT-EKG test

• Know Table 4.10, p. 104, or Box 5-3, p. 104 ACSM
• Criteria utilized in the laboratory which
  determines whether an individuals true VO2 max
  has been achieved includes the following
• 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
• The respiratory exchange ratio (RER) (ratio of
  the volume of carbon dioxide produced to the
  volume of oxygen consumed) increases to 1.15 or
  higher
• The subjects heart rate increases to within 10
  beats of the age-predicted maximum (MHR-220)
• Blood lactate levels rise above 8 mmol/liter