5. Cardiorespiratory Adaptations to Endurance Training

Question 1

Cardiovascular Adaptations

Answer 1

Increased oxygen delivery
Increased oxygen extraction

Question 2

Increased oxygen delivery causes increased

Answer 2

– Blood volume
– Cardiac output (= HR  SV)
– Coronary blood flow
– Muscle blood flow

Question 3

Increased oxygen extraction

Answer 3

– Arterio-venous oxygen difference

Question 4

what is Cardiovascular Adaptations

Answer 4

Adaptations which enhance oxygen
delivery

Question 5

why is blood volume post-training increased

Answer 5

Initially mainly due to increased plasma volume

Question 6

Increased Red Blood Cell Volume post-training

Answer 6

Initially red blood cell volume remains
unchanged then small increase
– ->erythropoietin (EPO) from liver and kidney

Question 7

what does erythropoietin (EPO) do

Answer 7

Acts to increase red blood cell production in the bone marrow

Question 8

Reduced Haematocrit is caused by

Answer 8

Plasma and red blood cell volume increase
Plasma volume increases > red blood cell volume

Question 9

Reduced Haematocrit effect on 02 delivery

Answer 9

Blood is less viscous
* Decreased resistance to flow
* Enhanced 02 delivery

Question 10

Increased Haemoglobin post-training

Answer 10

Increases in plasma volume and red cell volume become more even
* Haematocrit returns to normal
* Oxygen carrying capacity of blood remains enhanced due to increased haemoglobin

Question 11

Increased Stroke Volume PT

Answer 11

Increased at rest and during
submaximal exercise
* Maximal stroke volume increased

Question 12

Mechanisms of Increased Stroke
Volume

Answer 12

Greater ventricular filling due to
->Increased end-diastolic volume

Question 13

Greater ventricular filling due to :

Answer 13

– Increased blood volume
– Increased ventricular chamber size
– Greater diastolic filling time (due to reduced heart rate)

Question 14

→ Increased end-diastolic volume

Answer 14

– Greater stretch of ventricular wall (preload)
– Increased force of contraction (Frank-Starling mechanism)
– Greater ventricular output (increased stroke volume)

Question 15

Repetitive volume overload =

Answer 15

Increased chamber size:
* LV dilation

Increased wall thickness:
* Pressure overload
* Normalize wall stress

Question 16

HR PT

Answer 16

Reduced resting hr
Reduced hr at any submaximal work rate
Max hr unchanged

Question 17

Cardiac Output PT

Answer 17

CO = HR  SV
No change in CO at rest or at
submaximal exercise
Can increase substantially at max intensity

Question 18

Athlete’s artery

Answer 18

larger lumen dimension
<– wall thickness

Question 19

Increased Muscle Blood Flow PT

Answer 19

Muscle blood flow –> in exercise
(next session)
Greater –> in trained individuals

Question 20

Mechanisms of Increased Muscle
Blood Flow

Answer 20

–> capillary density (next session)
Greater capacity for vasodilation
–> sympathetic input
to smooth muscle in arteriole walls

Question 21

Improved Coronary Blood Flow PT

Answer 21

–> Internal diameter of coronary arteries (2-3x marathon)
Greater capacity for vasodilation in coronary arteries (2x marathon) (more important)

Question 22

Respiratory Adaptations PT

Answer 22

No change in lung capacity (no structural changes)
* Tidal volume
– Unchanged at submax work rates
– Max tidal volume increased
* Respiratory rate
– Slightly reduced at rest
– –>Max respiratory rate
* –>Max ventilation substantially (240 l·min-1)

Question 23

Increased Maximum Oxygen Uptake PT (R)

Answer 23

VO2 max –> 5-30 %
* Dependent on initial value
* Dependent on frequency, intensity, duration of exercise
* Genetic endowment
sets upper limit

Question 24

Increase in VO2 max post-training

Answer 24

50 % due to –> CO
50 –> arterio- venousO2 difference