LESSON 20 - what is VO2 max ?

Question 1

what is VO2 max ?

Answer 1

is when a plateau is reached (maximum oxygen consumption)

Question 2

define how physiological systems support an increase in VO2 (beginning from before lungs) :

Answer 2

• O2 uptake/inspired in the lungs
• O2 transport within the heart
• O2 utilization within the muscle

Question 3

define how physiological systems support an ↑ in VO2 (beginning from the muscles) :

Answer 3

• O2 utilization/consumption within the muscle becomes CO2 production
• CO2 flow within the heart (transport)
• CO2 expired from the lungs

Question 4

what are the two components of VO2 ?

Answer 4

convection and diffusion

Question 5

define convection :

Answer 5

movement through fluids (helps O2 uptake)

Question 6

what is the formula for VO2 ?

Answer 6

Q x a-vO2 difference

Question 7

what term is used for O2 uptake ?

Answer 7

VO2

Question 8

what term is used for flow of O2 rich blood ?

Answer 8

Q

Question 9

what term is used for O2 extraction ?

Answer 9

a-vO2 difference

Question 10

what is the formula for Q ?

Answer 10

HR x SV

Question 11

what is the formula for a-vo2 difference ?

Answer 11

CaO2 - CvO2

Question 12

what is CaO2 made up of ?

Answer 12

[Hb] and %SaO2

Question 13

what is the formula for diffusion ?

Answer 13

VO2 = Dmo2 x (PO2 capillary - PO2 mitochondria)

Question 14

what is the term used for O2 diffusion capacity for skeletal muscle ?

Answer 14

Dmo2

Question 15

what is the term used for driving pressure for O2 into mitochondria

Answer 15

PO2 capillary - PO2 mitochondria

Question 16

how many possible sites of VO2 max limitation are there ?

Answer 16

5

Question 17

name the 5 possible sites of VO2 limitations :

Answer 17

• pulmonary function
• cardiac output
• O2 carrying capacity of blood
• muscle diffusion
• skeletal muscles metabolic factors

Question 18

define pulmonary function :

Answer 18

atmosphere uptake within the lungs

Question 19

define cardiac output :

Answer 19

hearts ability to pump more blood

Question 20

define O2 carrying capacity of blood :

Answer 20

• blood itself (blood volume & hemoglobin)

Question 21

define muscle diffusion :

Answer 21

• SA for gas exchange
• driving pressure
• determine diffusive capabilities

Question 22

define muscle metabolic factors :

Answer 22

muscles themselves

Question 23

does reaching a maximal limit of ventilation determine VO2 max ?

Answer 23

reaching the maximal limit of ventilation alone does not determine VO2 max

Question 24

in regards to pulmonary diffusion (%SaO2) does the ability of lungs to transport inspired O2 from alveoli to pulmonary capillaries limit VO2 max ?

Answer 24

yes (you need good perfusion ability)

Question 25

do we hit a higher or lower VO2 max when we don't desaturate ?

Answer 25

we hit a higher VO2 max

Question 26

TRUE OR FALSE pulmonary diffusion is limiting capacity ?

Answer 26

TRUE

Question 27

when we have a greater resistance do we have a higher or lower alveolar ventilation ?

Answer 27

lower

Question 28

TRUE OR FALSE the following are all associated with each other ? - low O2 - ↑ in VO2 max - more diffusion to saturate

Answer 28

FALSE - high O2 - ↑ in VO2 more diffusion to saturate

Question 29

in regards to cardiac output ; does the heart's ability to raise cardiac output limit VO2 max ?

Answer 29

yes, the ability of the heart to increase cardiac output is a crucial factor in determining an individual's VO2 max.

Question 30

FILL IN THE BLANK "if the heart could pump more blood per minute, VO2 max would _________ ! "

Answer 30

increase

Question 31

is cardiac output a limiting factor for VO2 max ?

Answer 31

yes

Question 32

what is the formula for Q ?

Answer 32

Q = HR x SV

Question 33

in regard to O2 carrying capacity of blood ([Hb]) ; does the amount of O2 that we carry in the blood determine VO2 max ?

Answer 33

yes, the O2-carrying capacity of the blood, often represented by the concentration of hemoglobin ([Hb]), is a significant factor that influences an individual's VO2 max.

Question 34

what is hemoglobin ?

Answer 34

the protein in RBC that binds to O2 in the lungs and transports it to the tissues, where it is released to support cellular respiration

Question 35

TRUE OR FALSE ↑ [Hb] = ↑VO2 max ↓ [Hb] = ↓VO2 max

Answer 35

TRUE

Question 36

how many muscle diffusion capacity factors are there ?

Answer 36

3

Question 37

what are the three muscle diffusion capacity factors ?

Answer 37

- distance between capillary and mitochondria - contact area - pressure gradient b/w capillary and mitochondria

Question 38

is mitochondria pressure usually high or low ?

Answer 38

low

Question 39

what is a myocyte ?

Answer 39

a muscle cell

Question 40

what do the three muscle diffusion capacity factors do ?

Answer 40

improve ability to diffuse oxygen n

Question 41

define the muscle diffusion capacity factor "distance between capillary and mitochondria" :

Answer 41

↓ distance = ↑a-vO2 difference

Question 42

define the muscle diffusion capacity factor "contact area" :

Answer 42

↑ surface area = ↑a-vO2 difference

Question 43

define the muscle diffusion capacity factor "pressure gradient b/w capillary and mitochondria" :

Answer 43

↑ capillary pressure = ↑a-vO2 difference

Question 44

in regards to muscle diffusing capacity (↑a-vO2 difference) ; is there a limit to the amount of O2 that we can extract from arterial blood ?

Answer 44

yes, there is a limit to the amount of oxygen that can be extracted from arterial blood by the muscles, and this limit is often referred to as the arteriovenous oxygen difference (a-vO2 difference).

Question 45

FILL IN THE BLANK muscle venous blood contains a fair amount of O2 even at VO2 max... O2 saturation = ___ %

Answer 45

15 % (not all O2 has been extracted)

Question 46

is arterial content blood a limiting factor ?

Answer 46

no - arterial content blood isn't a limiting factor

Question 47

when at a further up altitude what happens to the pressure gradient for diffusion ?

Answer 47

lower pressure gradient for diffusion

Question 48

when we see a ↓driving pressure what does this mean for VO2 max ?

Answer 48

↓ VO2 max

Question 49

what does hypoxic mean ?

Answer 49

a state in which oxygen is not available in sufficient amounts at the tissue level to maintain adequate homeostasis

Question 50

can muscle diffusion capacity limit VO2 max ?

Answer 50

muscle diffusion capacity CAN sometimes limit VO2 max

Question 51

when we see lower hypoxia what does this mean for delta P and VO2 max ?

Answer 51

lower hypoxia = - reduction in delta P - ↓ VO2 max

Question 52

in regards to skeletal muscle metabolic factors ; is there a maximal ability of the muscle to utilize O2 for ATP resynthesis ?

Answer 52

yes, there is a limit to the maximal ability of skeletal muscles to utilize oxygen for ATP resynthesis during aerobic metabolism.

Question 53

name some factors related to the muscle's metabolic processes and cellular machinery :

Answer 53

- mitochondrial capacity - oxygen diffusion - enzyme activity - substrate availability

Question 54

discuss VO2 max related to mitochondrial volume :

Answer 54

- oxidative phosphorylation needs mitochondria - more mitochondria = more ability to use oxygen - type 2 more

Question 55

discuss VO2 max of whole muscle vs a piece of that muscle :

Answer 55

- skeletal muscle utilization is limiting their ability to increase their VO2 max

Question 56

TRUE OR FALSE in regards to what limits VO2 max; it depends on the person, their environment, and the type of exercise that they're doing ...

Answer 56

TRUE