CVS and Respiration Physiology

Question 1

What 4 physiological changes happen when you exercise?

Answer 1

Increased HR
Increased respiratory rate
Sweating
Feeling warm

Question 2

Why do these physiological changes come about when you exercise?

Answer 2

Increased muscle metabolism leads to

Increased oxygen consumption and CO2 production
Increased substrate consumption & by-prouct generation
Increased thermogenesis = sweating and skin vasodilation

Question 3

What factors change the source of ATP production?

Answer 3

Duration and intensity of exercise

Question 4

What is the phosphagen system, and when is it used?

Answer 4

ATP generation from creatine phosphate

Used in anaerobic, short-high intensity exercises

Question 5

What is anaerobic glycolysis, and when is it used?

Answer 5

Lactate generation to make ATP

Used in moderate-high intensity exercise

Question 6

What is aerobic respiration, and when is it used?

Answer 6

Glucose and fats are converted to ATP

Used in low-moderate intensity exercise

Question 7

What is the timing of ATP sources switching during exercise?

Answer 7

Immediately after starting exercise = creatine phosphate
Under 2 mins = anaerobic glycolysis peaks and does NOT reach 0 again
After 2 mins = aerobic metabolism slowly increases

Question 8

What exercise is the most suitable for fat burning?

Answer 8

Exercising for over 30 minutes, not too high intensity

Glycogen acts as source of glucose for around 20-30mins
Once glycogen stores are depleted = fatty acids become the substrate for aerobic metabolism

Question 9

When we exercise, what happens to cardiac output?

Answer 9

Sympathetic activity and epinephrine increases:

Acts on SA to increase HR
Increases cardiac contractility = increase SV

Increases peripheral vasoconstriction = increased VR
( positive feedback leading to increased SV )

Question 10

What is our resting cardiac output vs eexercise?

Answer 10

5 L/min resting
20-40 L/min exercise (sedentary vs trained)

Question 11

What happens to SV in response to exercise?

Answer 11

SV increases with exercise intensity

SV plateaus at 40-60% of cardiac output MAX

Question 12

Why does SV plateau?

Answer 12

Because the heart is at its MAX contractility

So any increase in cardiac output is due to increased HR

Question 13

Why does ESV decrease during exercise?

Answer 13

ESV decreases because of increased contractility = less blood left in the heart

Question 14

Why does EDV increase during exercise?

Answer 14

Muscles pump
Respiratory pumps
Redistribution of blood

All increasing venous return, causing an increase in blood present at rest

Question 15

What is the difference in SV at rest vs during UPRIGHT exercise, and why?

Answer 15

SV max during upright exercise = 2X SV at rest

This is due to an increase in EDV and decrease in ESV
SV = EDV - ESV

Question 16

In supine exercise, will the SV be greater or lower than upright exercise?

Answer 16

When lying down = CO increases because NO gravity pulling blood down

So increased venous return, causing increased EDV = increased SV

SV in supine exercise is LARGER than upright

Question 17

Are the SV max the same in supine and upright exercise?

Answer 17

Yes, they are the same because during max exercise SV reaches a plateau

This is because the heart has reached max contractile capacity

Question 18

What is the HR response to exercise?

Answer 18

HR rises linearly = increases with exercise intensity then plateaus

Question 19

What are the two equations for %HRmax calcualtions?

Answer 19

220 - age bpm

208 - (0.7 x age) bpm

Question 20

Will HR stay the same when you exercise at FIXED intensity for a long period?

Answer 20

NO, because of cardiovascular drift

Question 21

What is cardiovascular drift?

Answer 21

HR gradually increasing despite exercising at FIXED intensity

Question 22

Why does cardiovascular drift occur?

Answer 22

Because of increased heat generation = body initiates mechanisms to maintain constant temp

Sweating (sudomotor response) = reduces body fluid volume (blood volume) = reduce EDV = reduced SV

Skin vasodilatation to dissipate heat (vasomotor response) = reduced EDV = reduced SV

Reduced SV means HR must increase to maintain cardiac output

Question 23

If you eat a full meal before running, what will happen?

Answer 23

Feel discomfort due to blood flow redistribution to muscles

Question 24

What happens to blood vessels supplying muscle during exercise?

Answer 24

During exercise = skeletal muscle cell rapidly use oxygen

Reduced muscle O2 conc = vasoactive compounds locally released by endothelium

Act on smooth muscle of blood vessels = relax and dilate

Increase blood supply

Question 25

How does the cardiovascular system respond to FIXED intensity exercise for a prolonged period?

Answer 25

CO increases then plateaus through the exercise SV increases then drops due to sweating and vasodilation leading to reduced EDV and thus reduced SV Reduced plasma volume because of sweating HR increases to compensate for drop in SV and maintain CO at constant value (cardiovascular drift)

Question 26

How does the cardiovascular system respond to INCREASING exercise intensity until exhaustion?

Answer 26

SV increases until about 40-60% of CO then plateaus (may drop a bit in untrained) SV and PV will vary depending on training CO increases until certain level then plateaus HR increases proportionally to maintain CO HR doesn't plateau until reaching max CO (SV will plateau before that) So when HR hits max, CO also hits max

Question 27

What is the equation for ventilation?

Answer 27

Tidal volume x frequency

Question 28

What factors stimulate central and peripheral chemoreceptors?

Answer 28

Elevated CO2 due to increased tissue respiration Increased H+ during exercise (particularly heavy exercise)

Question 29

Why does H+ increase during exercise?

Answer 29

Because of elevated CO2 ad lactic acid accumulation

Question 30

What parts of respiration increase ventilation during exercise?

Answer 30

Increases in tidal volume and increased frequency of breathing (respiratory rate = RR)

Question 31

How does ventilation change just before exercise?

Answer 31

Increase can begin before exercise starts because of psychological factors & signals from muscles and joints Ventilation increases in proportion to metabolic needs Rapid increase in ventilation and tidal volume

Question 32

How does ventilation change during exercise?

Answer 32

Metabolic needs vs respiratory functions are in balance Oxygen supply and CO2 removal stabilized

Question 33

How does ventilation change when we stop exercising?

Answer 33

There is a lag before ventilation returns to resting rate This is due to excess post exercise O2 consumption (EPOC)

Question 34

What is Excess Post-Exercise O2 Consumption (EPOC) needed for?***

Answer 34

Phosphocreatine restoration Lactate removal Support ventilatory muscles

Question 35

What does VO2 measure?

Answer 35

Volume of oxygen that the body uses per minute Indicator of aerobic capacity

Question 36

What is the units of VO2?

Answer 36

mL/kg/min

Question 37

What does the Fick equation tell us and what is the equation?

Answer 37

VO2 = cardiac output x (arterioles - venous) oxygen conc difference

Question 38

What is VO2 max?

Answer 38

The maximum rate at which an individual can take in and use oxygen during maximal exercise

Question 39

What does having a higher VO2 max indicate?

Answer 39

Increased oxygen utilization = greater endurance potential

Question 40

What factors affect VO2 max?

Answer 40

Genetics Age Training Altitude

Question 41

What factors influence the Fick Equation (VO2 max)?

Answer 41

Cardiac Output = oxygen delivery by CVS HR, SV (EDV-ESV) Heart size & contractility Blood volume & composition Arterial - venous oxygen = oxygen utilization Muscle vascularization Mitochondria density OXPHOS enzymes Muscle type Metabolic enzymes

Question 42

What does training improve?

Answer 42

Exercise performance and capacity to resist fatigue Efficiency of energy utilization

Question 43

How does training affect SV?

Answer 43

Increased cardiac efficiency Increased plasma volume, LV compliance, ejection fraction, peak diastolic filling Decrease cardiac afterload

Question 44

How does training affect arterial oxygen conc?

Answer 44

Increased pulmonary function Increased ventilatory efficiency, lung diffusion capacity & ventilation/perfusion matching Decreased respiratory fatigue and decreased dead space (due to increased V-P matching

Question 45

How does training affect venous oxygen conc?

Answer 45

Muscle adaptation, lowering oxygen conc in venous blood (increases VO2 max) Increased mitochondrial content, oxygen utilization T1 fibres & time for lactate production Decreased time for oxygen extraction

Question 46

How can dead space be decreased?

Answer 46

By increasing ventilation-perfusion matching

Question 47

How does the blood adapt to training?

Answer 47

INCREASED BLOOD VOLUME Increase in both plasma and RBC volume = but more increase in plasma Leads to decreased hematocrit and blood viscosity

Question 48

What causes the increase in plasma volume post-training?

Answer 48

Increased albumin synthesis = increased oncotic pressure Thus, increased plasma volume = increased blood volume

Question 49

What happens to the heart in endurance athletes?

Answer 49

Left ventricular hypertrophy