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Assessment of Cardiorespiratory Fitness Heart Rates and Blood Pressures

Assessment of Cardiorespiratory Fitness Heart Rates and Blood Pressures. KNR 240 Fall 2004. Cardio-respiratory Endurance. “ The ability of the body to perform prolonged, large muscle, dynamic exercise at moderate-to-high levels of intensity”

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Assessment of Cardiorespiratory Fitness Heart Rates and Blood Pressures

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  1. Assessment of Cardiorespiratory FitnessHeart Rates and Blood Pressures KNR 240 Fall 2004

  2. 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 aerobicexercise.

  3. 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 cell’s 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.

  4. Oxygen Consumption • The most accepted index of work capacity is maximal oxygen consumption (VO2max). (“V”= volume of oxygen used per minute, “O2”=oxygen, and “max”=maximal 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.)

  5. 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.

  6. 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.

  7. 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?objectid=AF528CAA-72A4-4A5A-B65D37511AE58FE2for 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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).

  12. 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).

  13. 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)

  14. 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 VO2’s 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

  15. 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 individual’s 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 subject’s heart rate increases to within 10 beats of the age-predicted maximum (MHR-220) • Blood lactate levels rise above 8 mmol/liter

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