Lecture 22

Question 1

What is VO2 max a measure of?

Answer 1

cardio-respiratory fitness

Question 2

When you train for aerobic fitness, adaptations include what 5 things?

Answer 2

• heart
• vascular system
• muscles
• lungs
• increase in VO2 max

Question 3

What are major cardiovascular changes that occur to adapt to aerobic training?

Answer 3

• hypertrophy in the left ventricle

this results in increase in stroke volume, increase in CO and increase in contractility (more force per beat)

Question 4

What is a hypertrophy?

Answer 4

An increase in size

Question 5

If the LV size has increased and there is an increase in the size of the myocardial tissue, what does this mean has happened to the SNS?

Answer 5

The SNS has to increase the contractility to push out the blood

Question 6

What is the effect of training on stroke volume? Use a graph to explain this

Answer 6

Pre-training: as the treadmill speed increases, the stroke volume increases until but plateaus at about 115 mL/beat.

Post-training: as the treadmill speed increase, the stroke volume increase more linearly and begins to plateau at about 150 mL/beat

Question 7

What is the advantage of an increase in stroke volume for a trained person?

Answer 7

It means they can get more O2 to muscle so can work harder at different speeds

Question 8

How can we measure is SV has increased?

Answer 8

We can use heart rate as a measure of fitness as the SV adaptation occurs

Question 9

How does looking at HR tell us about an increase in SV? Describe a graph to help explain this

Answer 9

If we want to increase CO, we increase SV or HR. But if we only increase HR, the heart can’t refuel properly so the SV modification is better.
A graph shows watts (exercise intensity) on the x axis and heart rate on the y axis. For an untrained person, at 150 watts the heart rate was about 150 b/m. After training, the HR is only 125 b/m. At 210W, the untrained person is at maximal HR but the trained person ca go to 250 W before they max out because the SV has increased to get O2 to the muscles.

Question 10

Having a lower HR indicates that you are what?

Answer 10

you are fitter

Question 11

What are three changes to heart rate that occur with exercise training?

Answer 11

• resting heart rate decreases about 1 beat/min per week of training
• the submaximal heart rate decreases for the same intensity (this is more noticeable at higher submaximal intensities)
• the maximal HR doesn’t change with training

Question 12

There is no significant change to maximal heart rate with training. Instead, what does maximal heart rate decrease with?

Answer 12

age (ie. the older you are, the lower your maximal heart rate is)

Question 13

What is the submaximal heart rate?

Answer 13

Heart rate throughout various intensities between resting and maximal heart rate

Question 14

What happens to the thickness of the cardiac muscle wall?

Answer 14

It increases (LV hypertrophy)

Question 15

A good summary of Cardiovascular Adaptations to Aerobic Exercise can be found on slide 11, lecture 22

Answer 15

Okay go look at it bitch

Question 16

What are the adaptions to the vascular system in response to aerobic training?

Answer 16

• increased blood volume
• increased plasma levels
• increased red blood cells
• increase haemoglobin

Question 17

What causes the increase in blood volume and plasma levels in response to aerobic training?

Answer 17

ADH and aldosterone acting on the kidneys to reabsorb water

Question 18

What causes the increase in red blood cells and haemoglobin in response to aerobic training?

Answer 18

aldosterone signals the kidneys to increase EPO to increase Hb and RBC levels

Question 19

What increases dramatically because of adaptations to muscles in response to exercise training?

Answer 19

The maximal aerobic capacity - this influences the relative smaller changes in VO2 max

Question 20

What are three aspects of muscles that change in response to exercise training?

Answer 20

• the fibre type
• the capillary supply
• myoglobin amount

Question 21

How does the fibre type change in muscles in response to exercise training?

Answer 21

There is an increased size and number of type 1 fibres (type IIx change to be type IIa intermediate fibres which can change to be type 1 fibres).

Question 22

What do type 1 fibres have more of that gives them an advantage over type II fibres for aerobic training?

Answer 22

They have more mitochondria and oxidative enzymes so they can deal more readily with the aerobic pathways that involve carbohydrate and fat metabolism

Question 23

What happens to the capillary supply to muscles in response to exercise training? Why is this?

Answer 23

There is an increases number of capillaries because we need to get more O2 to the muscle to make use of the increased mitochondria and oxidative enzymes

Question 24

What is vasculogenesis?

Answer 24

This is the formation of new blood vessels

Question 25

What happens to the levels of myoglobin in the muscle in response to exercise training? Why is this important?

Answer 25

It increased by 75% to 80% which supports the increased oxidative capacity in muscle

Question 26

How does the level of mitochondria change with training and detraining?

Answer 26

The level of mitochondria increases with training. If you detrain, your level decreases back to baseline. But, if after a short time you retrain you get the mitochondria back

Question 27

What are two adaptations to the lungs in response to exercise training?

Answer 27

• the respiratory muscles get stronger

- there are more capillaries around the alveoli

Question 28

How do the respiratory muscles get stronger in response to exercise training?

Answer 28

The inspiratory muscles such as the diaphragm and the intercostal get stronger with use so you get hypertrophy with exercise of respiratory muscles so there is an increased tidal volume

Question 29

Why do we need more capillaries around the alveoli in response to exercise training?

Answer 29

Because we are bringing more O2 in so the alveoli increase the capillaries surrounding them so there is more gas exchange

Question 30

How does VO2 max change with training? Why is this?

Answer 30

The VO2 max increases with training because there is increase O2 carrying capacity, increased ability to metabolise glucose and carbohydrate for longer as you are using the oxidative pathway

Question 31

What thresholds improves with training? Why is this?

Answer 31

anaerobic threshold and lactate threshold
this is because you can use the aerobic threshold at a higher work rate after training and you don’t have to switch to your anaerobic so soon

Question 32

What happens to the combustion of lactic acid in response to exercise training?

Answer 32

We can combust lactic acid at a greater rate to use through the oxidative phosphorylation pathway

Question 33

How is lactic acid produced?

Answer 33

Glucose -> pyruvate -> acetyl CoA -> oxidative phosphorylation cycle

but

pyruvate can be converted to lactic acid so we know we are using the anaerobic system.
We can use lactic acid and combust it instead of pumping it into the blood stream

Question 34

What is the equation for the combustion of lactic acid? How does this effect the signal to slow down?

Answer 34

lactic acid -> pyruvate -> acetyl CoA
during aerobic training, the lactic acid can be combusted to pyruvate which decreases the [H+] and so we stop the signal to slow down

Question 35

How does genetics affect VO2max?

Answer 35

• finite VO2max range determined by genetics, training alters VO2max within that range
• identical twin’s VO2max more similar than fraternal’s
• accounts for 25 to 50% of variance in VO2max
• trained females < trained male

Question 36

• Two females, one 24 years old and one 55-years old, with the same body mass and same VO2max of 40 ml.kg-1.min-1 both run on a regular basis. If they were to both run at a 10 min per km pace, who would be expected to have a higher heart rate?
• A. The 24-year old
• B. The 55-year old
• C. The heart rates should be equivalent

Answer 36

• A. The 24-year old