Cardiovascular response to exercise Flashcards
What is Haematocrit?
The ratio of RBC’s to the total volume of blood
What is Acute adaptation to exercise?
Increases oxygen delivery to working muscles by increasing blood flow to working muscles and decreasing it to lower activity muscles
What is Chronic adaptation to exercise?
Delivers more oxygen to muscle mass, more effective oxygen delivery during sub-max exercise and increased VO2max
What influences Oxygen uptake & VO2max?
- Blood Volume
- Blood flow & Distribution
- Oxygen Extraction
- Cardiac Structure & Function
What is Fick’s Equation?
VO2 = HR x SV x (a-v)O2 difference
(a-v) = Arterio-mixed venous, HR x SV = Q (Cardiac Output)
What is Afterload?
Pressure against which the ventricle must contract, the higher the afterload the less blood will be ejected per heartbeat
What is Preload?
Amount of blood in the ventricle before contraction, this determines cardiac muscle length. Most important determining factor is venous return
Is the left ventricular volume larger in endurance athletes or power athletes? Why?
Endurance, an increase in preload causes a higher stroke volume causing eccentric hypertrophy
Why is posterior wall thickness and septal thickness larger in resistance athletes?
A higher afterload means a lower stroke volume leading to concentric hypertrophy
What is the difference between concentric and eccentric hypertrophy?
Eccentric - Results in increased ventricular volume
Concentric - Reduced ventricular volume
What does the Frank-Starling mechanism suggest?
The greater the stretch, the greater the contraction. If preload is increased, the ventricular fibre length is increased resulting in an increased tension of the muscle
What is SV determined by?
Preload, Afterload and Contractility
What is cardiac output directly related to as a result of SV?
Venous return and vascular resitstance
What are the endurance training adaptations for SV?
Higher Preload, Slower HR, Better contractility, Higher max SV
What are the endurance training adaptations for HR?
Lower HR, Max HR unchanged
What are the endurance training adaptations for Q?
Q = Cardiac Output
Lower Q as there’s an increased O2 extraction due to better muscle oxidative capacity
What is the difference between Autlogous and Homologous blood doping?
Autologous is their own blood, Homologous is another person’s
What is the definition of VO2max?
The maximum amount of oxygen your body can absorb and use during exercise
Why does blood flow increase to the skin during exercise?
To lose heat and cool the blood back down through sweating
What factors cause the vessels to widen during blood flow regulation?
- Decrease in pH
- Increase in hydrogen ions
- Increase in lactate
- Decrease in oxygen
- Increase in CO2
- Increase in temperature
What vegetable juice causes a vessel to dilate? Why?
Beetroot, contains nitrates which is converted to nitric oxide, a substance released by the endothelium
What does the vessel do if the blood pressure is low?
Dilates, so more blood will arrive and reach the destination
Why does a vessel constrict if the blood pressure is high?
Too much blood will be going through, so make the vessel smaller and reduce the amount of blood reaching the destination
What are the 3 main ways to regulate blood flow?
- Metabolic Regulation (Muslce metabolites & temperature)
- Endothelium-mediated vasodilation (Beetroot)
- Myogenic contraction (Pressure)
How does sympathetic activity affect blood flow?
During exercise, adrenaline will be created and detected by the receptors in the muscles causing vessels nearby to open or close depending on their location
True/False: Haematocrit always increases during exercise
False, total blood volume will increase but so will the plasma volume so the haematocrit doesn’t neccessarily increase
In what case will haematocrit increase?
Exercising at altitude
What 2 factors increase blood volume?
- Increase in plasma proteins
- Increase in total body water via alterations in kidney functions
How does blood volume change with exercise?
- Higher blood volume in trained athletes
- Increase in plasma volume early on (10 days) then increase in red blood cells (months)
True/False: Haematocrit increases after prolonged endurance training
False, the absolute plasma and red RBC volume increases whilst the haematocrit remains more or less the same.
What is Erythropoietin (EPO)?
A hormone that increases the rate of RBC production
