Cardiovascular and Respiratory Physiology in Exercise

Question 1

what are the effects of increased thermogenesis

Answer 1

sweating -> loss of water and electrolytes
skin vasodilation

Question 2

what are the intramuscular effects of increased metabolism

Answer 2

increased substrate consumption and generation of by products
increased thermogenesis
increased O2 consumption and CO2 production

Question 3

what is the phosphagen system
what type of exercise uses it

Answer 3

ATP generation from creatine phosphate

few seconds of anaerobic high intensity

Question 4

depletion of glycogen in exercise

Answer 4

glycogen acts as glucose source for 20-30 mins of exercise
once depleted, fatty acids become the substrate of aerobic metabolism

Question 5

what type of exercise is most suitable for fat burning

Answer 5

aerobic for a longer period of time

Question 6

CO increase in exercise

Answer 6

resting ~ 5 L/min
increase up to ~ 20 L/min for sedentary
~ 40 L/min for trained

Question 7

SV increase in exercise

Answer 7

in general plateaus at 40-60% CO max
resting ~ 65 mL/beat
untrained ~ 120 mL/beat
trained ~ 180 mL/beat

Question 8

EDV and ESV responses to exercise
why

Answer 8

EDV increases and ESV decreases

sympathetic stimulation increases contractility and decreased ESV

muscle pump, respiratory pump and redistribution of blood
increase venous return and EDV

Question 9

SV in supine exercise

Answer 9

increased venous return and EDV
increased SV

Question 10

SV in supine vs upright

Answer 10

SV max is the same in supine and upright exercise

action of the muscle pump in high intensity overcomes the increased EDV from supine

Question 11

HR increase in response to exercise

Answer 11

linearly with intensity

Question 12

calculating HR max

Answer 12

208 - (0.7 x age)

Question 13

will heart rate stay the same when you exercise at fixed intensity for a long period

Answer 13

cardiovascular drift: HR gradually increases with time despite fixed intensity

Question 14

explanation of cardiovascular drift

Answer 14

increased heat generation causes sweating and reduced body fluid volume as well as skin vasodilation

leads to reduced EDV and SV
HR increases to maintain CO

Question 15

what happens to blood vessels supplying muscle during exercise

Answer 15

reduced muscle O2 concentration
endothelium releases NO and prostacyclin
vasodilation

Question 16

blood flow redistribution during exercise

Answer 16

away from other organs to muscle
heart remains the same

Question 17

how does the body increase ventilation during exercise
by how much

Answer 17

peripheral and central chemoreceptors sense changes in blood gases and chemistry
pain and emotional stimuli through hypothalamus
receptors inn muscles and joints

all cause medullary respiratory centre to increase ventilation

can increase up to 25 times

Question 18

what causes the O2 deficit at the start of exercise

Answer 18

due to mismatch in supply and demand

Question 19

what is excess post exercise O2 consumption

Answer 19

phosphocreatine restoration
lactate removal
support ventilatory muscles

Question 20

VO2 max

Answer 20

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

Question 21

factors affecting VO2 max

Answer 21

genetics
age (typically declines with age)
training status
altitude (lower at higher altitudes)

Question 22

VO2 equation

factors that affect it

Answer 22

VO2 = CO x (a-v) O2 difference

cardiac output: delivery by CVS
HR, SV, contractility, volume, composition

atrial-venous oxygen: O2 utilisation
muscle vascularisation, mitochondria density, oxphos, muscle type and enzymes

Question 23

adaptions to chronic exercise training
endurance and strength

Answer 23

improves exercise performance and capacity to resist fatigue and efficiency of energy utilisation

endurance improves maximal oxygen consumption
strength improves muscles size and strength

Question 24

CVS adaptions to chronic endurance exercise:
blood volume
ventricles
afterload
EDV
LV compliance
EF
resting HR

Answer 24

blood volume - increased
ventricles - remodelling
afterload - decreased
EDV - increased
LV compliance - increased
EF - increased
resting HR - decreased

Question 25

why does blood volume increase post training

Answer 25

one of the earliest training adaptions
due to increase in both plasma and RBCs
greater increase in plasma than RBCs to prevent larger hematocrit and viscosity

Question 26

what does increased erythropoietin lead to increased blood volume

Answer 26

increases RBCs leading to increased O2 carrying capacity

Question 27

what does increased albumin synthesis lead to increased blood volume

Answer 27

increases oncotic pressure leading to increased plasma volume

Question 28

why does left ventricle size increase post training

Answer 28

increased diameter and wall thickness
not pathological

Question 29

how does stroke volume increase with training

Answer 29

increased EDV by LV compliance, size and blood volume
decreased ESV by decreased peripheral resistance, increased LV muscle mass and contractility

Question 30

why does resting HR decrease post training

Answer 30

increased resting SV leads to increased parasympathetic activity

Question 31

respiratory adaptions to training

Answer 31

increased respiratory muscle strength
increased efficiency and lung diffusion capacity
increased V/Q matching and reduced dead space

Question 32

how does the respiratory rate change with training

Answer 32

decreases due to more efficient O2 use

Question 33

is training of the respiratory system critical to endurance performance

Answer 33

overbuilt to withstand peak exercise
may not be as important as training other systems

usually does not limit endurance performance
CVS and muscle are more likely to limit