Topic 1: Maximal Oxygen Consumption (VO 2max ) Testing

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1 Topic 1: Maximal Oxygen Consumption (VO 2max ) Testing Laboratory Manual Section 02 HPHE 6720 Dr. Cheatham Goals for this Topic Understand the physiological basis for VO 2max Understand the use of indirect calorimetry to measure VO 2 Become familiar with the protocols, equipment, testing procedures to measure VO 2max Become familiar with using the two different metabolic measurement systems Be able to collect, interpret, and analyze VO 2max data 1

2 Physiological Basis VO 2 = CO (CaO 2 CvO 2 ) VO 2 = V A (F I O 2 F E O 2 ) Metabolic Computations VO 2 2

3 Metabolic Computations VO 2 Metabolic Computations VCO 2 3

4 Metabolic Computations RQ How is VO 2max Expressed? Absolute VO 2 The actual amount of oxygen your body utilizes Usually in LO 2 /min or mlo 2 /min Relative VO 2 The amount of oxygen your body used per kilogram of bodyweight mlo 2 /kg/min Allows comparison between people of different sizes. 4

5 Absolute vs Relative VO 2 Body Mass = 230 lbs (104.5 kg) VO 2max = 5 LO 2 /min VO 2max = 47.8 mlo 2 /kg/min Body Mass = 150 lbs (68.2 kg) VO 2max = 4 LO 2 /min VO 2max = 58.7 mlo 2 /kg/min Protocols to Assess VO 2max Mode of testing should be appropriate to the individual being tested. For athletes, should be sport specific. Treadmill vs. Cycle Ergometer vs. Other Incremental Stages Continuous vs. Discontinuous 5

6 Protocols to Assess VO 2max Protocols to Assess VO 2max General Protocol Guidelines: A beginning stage that is at a low intensity in order to allow for an adequate warm up. A consistent and gradual increase in exercise intensity. An incremental increase in exercise intensity as to allow for the test to finish in an appropriate amount of time (8 15 minutes). A protocol that is appropriate to the subject. I.e. walking vs. running, appropriate treadmill speed (if treadmill is used). 6

7 Protocols to Assess VO 2max Treadmill Protocols Established Protocols Bruce, Modified Bruce Balke, Naughton, Astrand (Not the Cycle Test) Protocols to Assess VO 2max 7

8 Protocols to Assess VO 2max A generalized treadmill protocol: Example Treadmill Protocol 2 minute walking stage (3.0 mph, 0% grade) 2 minute running stage (appropriate running speed, 0% grade) 1 minute stages keeping running speed constant and increasing grade 2.5 % to 3%) Note: If possible, it is advantageous to have the subject get on the treadmill before the actual test and to increase the treadmill speed until a comfortable running speed is achieved. Protocols to Assess VO 2max Cycle Ergometer Protocols Example Cycle Ergometer Protocol 2 minutes at 40 Watts (female) or 60 Watts (male) 1 minute stages in which the Watts are increased 20 Watts every minute 8

9 Equipment to Measure VO 2max Mode of Testing Treadmill Cycle Ergometer Mechanically braked cycle (Monark) Magnetically/Electronically Braked Equipment to Measure VO 2max Metabolic Measurement Cart Allows for the measurement of Ventilation, O 2 and CO 2 of expired air Does calculations for you 9

10 Equipment to Measure VO 2max Heart Rate Measurement Telemetry (Polar HR Monitor) ECG (CM5) Equipment to Measure VO 2max Ratings of Perceived Exertion (RPE) Borg 6 20 Scale Borg 0 10 Scale Use standardized directions During the exercise test we want you to pay close attention to how hard you feel the exercise work rate is. This feeling should reflect your total amount of exertion and fatigue, combining all sensations and feelings of physical stress, effort, and fatigue. Don t concern yourself with any one factor such as leg pain, shortness of breath, or exercise intensity, but try to concentrate on your total, inner feeling of exertion. Try not to underestimate or overestimate your feeling of exertion; be as accurate as you can. 10

11 Equipment to Measure VO 2max Performing the Test Greet the patient / client Explain the test, equipment, etc. Obtain informed consent Obtain baseline measurements Record environmental conditions Record age, height, weight Calculate predicted Max HR, 85% Max HR Record resting HR and BP Calibrate Equipment Instruct patient / client on how to perform the test Treadmill use Borg Scale 11

12 Performing the Test Instrument subject ECG or Polar HR Mouthpiece / Noseclips Begin test Record appropriate measurements during test HR usually every 30 sec RPE, BP at end of each stage Use appropriate data recording sheet Terminate test when appropriate Allow subject to actively cool down Monitor HR and BP Criteria for Test Termination 12

13 Achieving True Maximal Measurement Objective criteria are established to determine whether a true maximal measurement was achieved. Plateau in oxygen consumption Increase less than 150 mlo 2 /min with increasing exercise intensity Respiratory Exchange Ratio (RER) VCO 2 /VO 2 RER > 1.1 or 1.15 Heart Rate Within 10 beats of age predicted max HR RPE Scale RPE > 17 Achieving True Maximal Measurement 13

14 Achieving True Maximal Measurement Achieving True Maximal Measurement 14

15 VO 2max Statistics Olympic Athletes VO 2max Statistics Age 15

16 VO 2max Norms VO 2max Norms 16

17 VO 2max Class Project Research Question: Is there a statistically significant difference between VO 2max values obtained from a treadmill test versus a cycle ergometry test? Methods: At least six students will perform a VO 2max test on a treadmill and a cycle ergometer We will then perform some statistical analyses to answer the research question. 17