W17. VO2 max and Gas Exchange Thresholds

Question 1

What is the definition of VO2 max?

Answer 1

Max volume of oxygen that can be measured during aerobic exercise

Question 2

Why is VO2 max measured?

Answer 2

Good indicator for cardiorespiratory fitness

Question 3

What does VO2 max represent?

Answer 3

The functional capacity of circulation (O2 delivery and O2 extraction)

Question 4

What organisation does VO2 max criteria come from?

Answer 4

BASES

Question 5

What is the most important BASES VO2 max criteria?

Answer 5

A plateau in O2 uptake (or an increase of no more than 3% / 2ml/kg/min

Question 6

Essentially how do we know when we are looking at VO2 max?

Answer 6

If exercise intensity keeps increasing but VO2 doesn’t continue with it

Question 7

When should the term VO2 peak be used instead?

Answer 7

If there is no plateau

Question 8

What are some secondary VO2 max criteria?

Answer 8

RPE of 19 or 20
Subjective fatigue
Final RER of greater than 1.15
Reach within 10 beats of maximal HR

Question 9

Why might there not be a plateau?

Answer 9

May have been discomfort or decrease in motivation

Processing method may not be able to identify a plateau

Question 10

What are the main physiological determinants of VO2 max?

Answer 10

Maximal CO
Skeletal muscles (inc ability to extract oxygen)
O2 carrying capacity of blood

Question 11

How does body size affect VO2 max?

Answer 11

Positive correlation between body size and VO2 max

If expressed relatively, effect of body size is reduced

Question 12

How does sex affect VO2 max (and what ages do they peak)?

Answer 12

No difference until age 12+
Peaks for boys between 17-21, peaks for girls between 12-15
Women generally display 15-30% lower than men

Question 13

How does age affect VO2 max?

Answer 13

Decreases by 1% per year from mid 20s unless training occurs

Question 14

What sport produces the highest VO2 max scores on average?

Answer 14

Highest: Cross country skiing

Question 15

What does GET stand for?

Answer 15

Gas Exchange Threshold

Question 16

What is the first GET known as?

Answer 16

Ventilatory Threshold (VT)

Question 17

What is the second GET known as?

Answer 17

Respiratory Compensation Point (RCP)

Question 18

What test can be used to determine GET and VO2 max?

Answer 18

Progressive maximal test (to limit of tolerance)

Question 19

Why is VT measured?

Answer 19

Indicates the point where blood flow of exercising muscle is no longer sufficient to meet metabolic demand

Question 20

What are some of the physiological causes of VT?

Answer 20

First sign of bicarbonate buffering onset

Question 21

What does RCP depict?

Answer 21

The final phase from buffering to exercise acidosis (lactic acid)

Question 22

What is the period between VT and RCP called and how long does it last?

Answer 22

Isocapnic buffering zone

Only lasts a couple of mins

Question 23

What is the period between RCP and the end of exercise called and what does it mean?

Answer 23

Hypocapnic hyperventilation phase

Means exercise can only be continued for a few minutes

Question 24

How do you determine VT?

Answer 24

Using the V Slope method

Plot VO2 and VCO2 and look for where lines of best fit intersect

Question 25

How do you determine RCP?

Answer 25

Plot VE and VCO2 and look for where lines of best fit intersect

Question 26

What is the Ventilatory Equivalents method?

Answer 26

Most common method used in SES and can determine VT and RCP

Question 27

How does the Ventilatory Equivalents method work?

Answer 27

VT: First point where VE/VO2 increases without increase in VE/VCO2
RCP: First point where VE/VO2 and VE/VCO2 increase together

Question 28

What is the dual criterion method?

Answer 28

Most accurate GET method

Question 29

How does the dual criterion method work?

Answer 29

Combines ventilatory equivalent method and end tidal gas tension method

Question 30

What should you always do when checking VT and RCP (regarding methods)?

Answer 30

Always use more than one to double check and back up the results