Adaptations to endurance training Flashcards
VE?
Minute ventilation
VO2?
Rate of oxygen uptake by the lungs.
QO2?
Rate of oxygen consumed by cells.
VCO2?
Rate of carbon dioxide output by lungs.
QCO2?
Rate of carbon dioxide production by cells.
R?
Respiratory exchange ratio (VCO2/VO2)
RQ?
Metabolic quotient (QCO2/QO2)
What requirements are there of normal gas exchange between muscle and the environment?
1) Effective lungs and chest bellows.
2) Effective pulmonary circulation so regional blood flow is matched to appropriate ventilation.
3) Heart capable of pumping the quantity of oxygenated blood necessary to to sustain tissue energy exchange.
4) Effective system of BV that can selectively distribute BF to match tissue gas exchange requirements of working muscles.
5) BF with an adequate Hb concentration
6) Respiratory control mechanisms capable of regulating arterial blood gas tensions and pH.
How do you measure O2 consumption during exercise.
Mouth piece - valve allows air to be taken in from atmosphere and also allows expired air to go into a Douglas bag. Measure concentrations and volumes.
Work done on ergometer - can be controlled. Set braking resistance and pedal frequency - allows power output (watts) to be set.
To calculate VO2 and VCO2 we also need to know - barometric pressure and temperature.
Explain the relationship with low exercise intensity and VE, VO2 and VCO2.
At low intensities - all rise linearly with increasing power output.
What is the anaerobic/lactate threshold?
HIghest exercise intensity/O2 uptake that is not associated with an elevation in blood lactate concentrations above the pre exercise intensity.
What happens to LA as work intensity increases?
As work rate increases, lactic acid is buffered by sodium bicarbonate producing CO2.
THis Co2 must be eliminated to prevent pCO2 rising.
Increased pCO2 is the driving force for increased ventilation.
VCO2 and VE increase more than VO2
What happens as work rate increases to max?
[H+] from HCO3w- decrease and stimulates carotid bodies to increase VE even more. This a respiratory compensation for a metabolic acidosis.
What changes happen to the CV system during dynamic exercise?
QO2, HR, SV, MAP all increase.
TPR decreases as BV in legs dilate to allow O2 in.
Explain how the pulmonary system may limit the body’s ability to utilise O2 (Limit VO2 max)
Limiting in high altitudes and those with COPD or asthma.
We know this because VO2 max can increase when increase when taking in O2 enriched air.
Explain how oxygen carrying capacity may limit the body’s ability to utilise O2 (Limit VO2 max)
Blood doping increases VO2 max.
Erythropoietin (EPO) - genetically engineered version of natural hormone produced by kidneys to stimulate RBC production.
What happens is someone has a mutated EPO receptor?
Always on! EPO always being produced.
Explain how cardiac output may limit the body’s ability to utilise O2 (Limit VO2 max)
Max CO and man O2 uptake correlate suggesting that the size of the heart or max SV is key in determining max O2 uptake.
Shown if you isolate and just train one knee - O2 uptake is 2-3 x higher in isolated knee than when working the whole body.
What is the Fick equation?
VO2 = CO x (CaO2 - CvO2).
Define training.
TO cause biological adaptations to improve performance.
What are 4 other the general principles of training?
Overload
Specificity
Individuality
Reversibility
What is the highest level of fitness determined by?
VO2 max
With endurance training you get an elevated CO/SV - why?
Improved diastolic filling and increased EDV…
Expanded plasma volume…increased venous return…prolonged diastole…enlargement of ventricular volume…greater ventricular complience.
FRANK STARLING
What 4 other adaptations does sub-max training cause?
Decreased vasopressin and renin (vasoconstrictors)
Decrease relative VO2.
Decreased Respiratory Exchange Ratio.
Increase exercise intensity before OBLA.
What happens to mitochondria with exercise?
increase in number and sixe and increase the mitochondrial enzymes.
What happens to the fuel source after a period of endurance training.
Total energy expenditure is the same but fat combustion increases and CHO and glycogen are saved.
What is PGC-1?
The master regulator of mitochondrial biogenesis and also regulates other slow genes suchas slow troponin and slow myosin.
What stimulates PGC-1
AMP activated kinase
Calcium:calmodulin activated kinase
p38 MAPK increases the phosphorylation of PGC-1
What changes occur to BF and BVs with endurance training?
Increase capillary density through angiogensis.
Increase transient time (blood flows through more slowly - therefore more time for O2 to diffuse.
Increases O2 extraction.
Can fibre types convert?
IIX - IIA - YES!
IIA - I - VERY HARD!!
