U3AoS2 - Oxygen Uptake and Acute Responses Flashcards
Oxygen uptake at rest
Minimal oxygen consumption as ATP demand is low.
Oxygen consumption at rest
0.3 L of oxygen per minute
What fuel substrates are used at rest?
Carbohydrates and Fats
The amount of oxygen entering the bloodstream is…
Proportional to the amount used by tissues for oxidative metabolism
What happens to oxygen consumption as intensity increases?
As intensity increases, consumption of oxygen increases for greater ATP resynthesis.
As the athlete moves from rest and into activity
O2 uptake increases as the body attempts to meet oxygen demand.
- Cardiovascular and respiratory systems increase O2 uptake and transport
Muscles
utilize and consume oxygen
Transition from rest to exercise
Shortfall between the amount of O2 required for exercise and amount supplied.
This is called oxygen deficit
Oxygen deficit
- Oxygen demand exceeds oxygen supply
- Anaerobic systems will be dominant
- Once oxygen becomes available to meet demand, steady state is reached.
Why does oxygen deficit occur?
Respiratory and Cardiovascular system take time to adjust to the new oxygen demand.
- Amount supplied lags behind amount needed
Steady state can only be reached when
Necessary adjustments are made to increase oxygen supply
Increased:
- respiratory frequency
- tidal volume
- heart rate
- stroke volume
Steady State
Oxygen supply meets oxygen demand
- aerobic steady state
- ATP supplied aerobically
- Heart rate and oxygen consumption remain constant
- No need for further increase oxygen uptake and little reliance on anaerobic pathways
How long does it take for steady state to be reached?
One minute or more depending on intensity for oxygen supply to increase sufficiently to meet oxygen demands.
Physiological response during Steady State
- coincides with a plateau in heart rate and ventilation as enough oxygen is reaching the working muscles
If intensity increases again
- demand for ATP and oxygen uptake increases
- short delay before O2 uptake increases sufficiently
- anaerobic systems briefly increase contribution until another steady state reached.
A steady state can only be reached when
Lactate production is less than lactate removal.
- Steady states can only be help up to and including Lactate Inflection Point
Oxygen deficit in trained athletes
Oxygen deficit is reduced due to athletes attaining steady state sooner.
EPOC stands for
Excess post-exercise oxygen consumption
EPOC
Body is taking up, transporting and consuming more O2 than is required at low intensities
Consuming more O2 as it is trying to return the body to pre-exercise state
Fast Part
First 3 minutes
- Resynthesize PC and ATP
- Restore O2 to the myoglobin
Slow Part
Following 3 minutes
- oxidation of hydrogen ions
- convert lactic acid to CO2 and H2O
- return core temperature, HR and V to pre-exercise levels
- Convert lactic acid to glycogen
Factors affecting duration of EPOC
- duration
- intensity
- fitness levels
The greater the intensity the greater the EPOC
Impact of training on O2 deficit, steady state and EPOC
- lower HR
- faster recovery
- improved ability to transport O2
- reach steady state faster
Anaerobic activities
- increased oxygen deficit and EPOC