Oxygen Uptake Kinetics

Question 1

Define oxygen uptake kinetics

Answer 1

Study of the physiological mechanisms responsible for the dynamic VO2
response to exercise & recovery

Question 2

How many dynamic response phases are there?

Answer 2

3

Question 3

What does oxygen uptake determine?

Answer 3

Rate of aerobic/anaerobic energy transfer

Tolerable duration of exercise

Question 4

What controls/limits oxygen uptake kinetics? (2)

Answer 4

Rate of O2 delivery to active muscle

Ability of muscle to utilise O2

Question 5

What causes the O2 deficit?

Answer 5

A lag in VO2

Question 6

Why does the VO2 lag occur? (2)

Answer 6

Intrinsic inertia in cellular metabolic signals

Sluggishness of O2 delivery to mitochondria

Question 7

What does the O2 deficit represent (simply)?

Answer 7

Difference between total VO2 and total that would be present had steady state occurred from start

Question 8

Name each (3) phases of oxygen uptake kinetics:

Answer 8

P1: Cardio-dynamic phase
P2: Fundamental (fast) component
P3: Steady state or slow component

Question 9

How long does P1 take?

Answer 9

Approx 15 secs

Question 10

Describe P1:

Answer 10

Inc in VO2 reflects inc in VR

Blood coming back to lungs hasn’t had inc in O2 extraction

Question 11

Describe P2:

Answer 11

VO2 continues to rise exponentially (quicker steady state is reached = less o2 deficit)

Question 12

Describe P3 (steady state) :

Answer 12

VO2 achieves steady state, CO plateaus

Response amplitude is lower post training

Question 13

Describe P3 (slow component) :

Answer 13

VO2 continues to increase, rather than plateau
Additional O2 cost drains body of fuel stores rapidly
Larger slow component = shorter exercise tolerability

Question 14

When is P3 known as ‘steady state’ and when is it now as the ‘slow component’, and why?

Answer 14

Steady state: When exercise is below LT
Slow component: When exercise is above LT
Why: Because VO2 still increases in P3 (SLOWLY) during SLOW component

Question 15

Define amplitude (in relation to o2 kinetics) :

Answer 15

Signifies O2 demand of the working muscle

Question 16

What does time delay mean (in relation to o2 kinetics) :

Answer 16

Time elapsed before O2 expired reflects demand of working muscles (length of time before P2 starts

Question 17

What does time constant mean (in relation to o2 kinetics) :

Answer 17

Time taken to reach 63% of amplitude

Speed of response

Question 18

What does mean response time mean (in relation to o2 kinetics) :

Answer 18

Overall kinetic response

Time taken to reach 63% of VO2 increase above baseline

Question 19

What is priming? (in relation to o2 kinetics)

Answer 19

Any activity that takes place before the main bout of exercise

Question 20

Why is priming done?

Answer 20

To try and modify VO2 kinetics response

Question 21

How is priming done?

Answer 21

Exercise intensity has to exceed LT to modify VO2 kinetics response

Question 22

What effect does priming have on O2 deficit?

Answer 22

Priming decreases O2 deficit

Question 23

What is one of the major advantages of using priming?

Answer 23

It doesn’t need to focus on the same specific muscles to be of benefit

Question 24

What are the two overall benefits?

Answer 24

Speeds up the overall kinetic response

Reduces slow component phase

Question 25

Explain the specifics of priming:

Answer 25

An exercise bout of 6 mins approx takes place
Vasodilation occurs (academia)
More nutrients can get to working muscles / shift O2 dissociation curve to the right

Question 26

What was EPOC previously known as?

Answer 26

Oxygen debt

Question 27

What does EPOC stand for and represent?

Answer 27

Excess post exercise oxygen consumption

Represents VO2 above what is normally consumed at rest

Question 28

How long does EPOC last and what does this depend on?

Answer 28

Can be very short or very long or in between

Depends on intensity, duration, training status, sex

Question 29

What is EPOC affected by?

Answer 29

Anaerobic metabolism level in previous exercise bout

(Resp, circ, horm, ionic, thermal adjustment that inc metabolism during recovery

Question 30

What is the percentage split between fast and slow EPOC components?

Answer 30

Fast: 20%
Slow: 80%

Question 31

Give some fast component roles:

Answer 31

Restore PCr stores
Restore myoglobin stores
Restore blood o2 stores
Restore sodium/potassium balance in nerves/muscles
Keeps blood flow and ventilation elevated

Question 32

Give some slow component roles:

Answer 32

Glycogen resynthesis
Lactate converted to glucose
Lactate converted to pyruvate in muscle
Elevated metabolic rate (body temp)