Lecture 29: Central Cardiovascular Adaptations to Exercise Flashcards
What is the effect of aerobic exercise on blood volume?
Increases blood volume
10% increase after 24 hours
Why does exercise training lead to an increase in plasma volume in the short term?
Chronic anaemia: huge increase in blood plasma, with a stagnation of erythrocyte production
What happens to blood composition with regular training?
Increased plasma volume and erythrocyte number
There is overall a greater increase in plasma volume than erythrocytes
How is RBC production stimulated due to endurance training?
Exposes kidney to hypoxia
Increased EPO (erythroprotein) secretion
Increased heamatopoeitic stem cell production in the bone marrow
Increased RBC production
Describe the time course changes in blood plasma and erythrocyte production.
Immediate increase in blood plasma volume production, where rate of increase declines after around 10 sessions (short term adaptation)
Erythrocyte production remains at 0 at about 20 sessions, then increases (long term adaptation)
Overall increase in erythrocyte production not as great as plasma volume
What two things can be injected to enhance blood composition (blood doping)?
EPO’s and RBC’s
What effect does exercise training have on cardiac structure?
Increased ventricle wall thickness
Increased ventricle filling volume (EDV)
Eccentric hypertrophy (increase in proportion to one another)
What are the functional adaptations made to cardiac function due to endurance training?
Increased contractility of heart (greater EDV, sometimes lower ESV, greater ejection fraction)
Increased stroke volume
Max heart rate achieved at higher intensity
Increased cardiac output at high intensities
At what point does stroke volume tend to plateau for elite endurance athletes?
40-50% exercise intensity
Does continue to increase in elite endurance athletes, especially at very high intensities
How does cardiac output differ for elite and non-elite athletes?
Elite athletes have a lower sub-max cardiac output at low intensities and a higher cardiac output at high intensities
Why is having a reduced heart rate advantageous for endurance exercise?
More time for ventricular filling, therefore greater EDV
Why is heart rate recovery quicker in trained athletes?
More pronounced activation of parasympathetic nervous system
Why can heart rate recovery time be a useful indicator in clinics?
Powerful predictor of mortality
How can endurance and resistance exercise differ in their effects on cardiac hypertrophy?
Resistance:
Concentric hypertrophy
Increased wall thickness
More powerful contractions
Endurance:
Eccentric hypertrophy
Increased chamber size and wall thickness
Increased EDV therefore increased stroke volume
What are the mechanisms for increased eccentric hypertrophy with endurance exercise?
Increased blood flow
Increased blood volume
Decreased heart rate
Increased compliance
