Oxygen Kinetics And Intensity Domains Flashcards
Why are exercise intervals 3-4 mins during LT/VT tests?
When you begin exercising your body can’t meet the oxygen demand so energy systems used begin with anaerobic as its much quicker. The 3-4 mins allows the physiological systems to essentially ‘catch up’.
Why do we get an oxygen debt when we finish exercising?
Because your body needs to replace the O2 in muscles, blood, PCr-ATP stores, remove CO2 and blood lactate.
Define O2 deficit
Difference between the total O2 consumption during activity and the total that would be consumed had steady state been achieved onset.
Do endurance athletes have a faster or slower O2 kinetics transition? And why?
Faster. Likely due to cardiovascular adaptations.
What are the 3 stages responsible for the increase in oxygen consumption from rest to steady state?
Phase 1 - the initial jump in VO2, this is cardio dynamically controlled
Phase 2 - exponential increase, by the pressure of gases in the system (increase in CO2, drop in O2 and depleted PCr stores signals to aerobic system)
Phase 3 - steady state, where you can continue at a fixed workload. O2 consumption = O2 requirement
What is the primary cause of VO2 increase during phase 1 on-kinetics?
Vagal withdrawal and muscle pump action increase the HR and SV.
Therefore an Instant increase in CO and pulmonary blood flow due to this. Also increase in ventilation.
Why do superior VO2 kinetics indicate superior aerobic fitness?
You’d have a smaller O2 deficit; reach steady state quicker; smaller O2 debt; smaller disturbances in metabolic products eg. Lactate, as spent less time in anaerobic system; smaller perturbations in H+ conc and PCr
What may limit O2 kinetics / why is there a lag in O2 consumption?
Transport and delivery of O2
O2 utilisation
A co-ordinated response from pulmonary, CV and muscular
The lag is covered by intramuscular stores, depletion of PCr and transient increases in glycolysis.
What is the slow component?
When exercising above sub-max intensities, there is an additional O2 cost than what is predicted from the VO2-work rate relationship. It takes longer to reach steady-state, at severe intensities you never reach steady state.
Why do we get the slow component?
At higher intensities you’re thought to be less efficient and there is an increasing recruitment of type IIb fibres. They consume more O2 than type I fibres for a given workload.
Why do endurance trained athletes have increased oxygen kinetics?
Greater mitochondrial density
Faster increase in bioenergetic
Greater increase in CO
Greater proportion of blood to type I fibres that require less O2
Large regional blood flow to active muscles
Increased mitochondrial quality
