other concepts (VO2 max, RER, VCO2, Ventilatory Threshold, Lactate Threshold, a-vO2 diff, OBLA, EPOC Flashcards
what is the a-vO2 difference?
a-vO2 difference is the difference in blood O2 concentration in arteries and veins
what does the a-vO2 determine?
how much oxygen is utilized by the body during activities
how is the a-vO2 difference measured?
measure the O2 level in the arterial blood before it arrives the muscle, then measure the O2 in venous blood that drains from the same muscle
what is the definition of VO2 max?
the maximum amount of O2 that can be taken in and utilized for metabolic production of ATP
unit: ml/kg/min
how is VO2 max measured?
- Simulate the sport that the athlete is good at
- breath through a 2 way valve system (air in from the room, air out measured by sensors for both volume and O2 concentration)
- gradually increase workload until the oxygen consumption plateaus
what limits the VO2 max in a well trained person
the person has enough mitochondria to utilize the oxygen very well; however, the stroke volume of the person is not enough for the oxygen to supply to all the muscles
thus oxygen delivery is what limits the person
what limits the VO2 max in an untrained person?
in an untrained person, even if the blood flow is high, there is not enough mitochondria to use them up.
thus the oxygen utilization is what limits the person
what are some physical changes in a person with marathon training
- increased stroke volume
- slower heart rate
- increased cardiac output
- more capillaries
- more mitochondria
- arteries more elastic
- enhanced ventilatory control
- greater VO2 max
- lactate threshold improvement
…
What is VCO2
the difference between the CO2 expired and the amount of CO2 inspired
What is RER
The ratio between VCO2 and VO2
= amount of CO2 produced by the body (VCO2)/amount of O2 consumed by the body (VO2)
The RER tells us what metabolic systems are being used within the working muscle
carbs: 6O2 + C6H12O6 = 6CO2 + 6H2O + 38 ATP
hence RER = 6:6= 1:1 or RQ=1
Fats: 23O2 + C16H32O2 = 16CO2 + 16 H2O +129 ATP
hence RER=16:23 or RQ=0.7
what is ventilatory threshold?
-When the intensity of training increases gradually (like a VO2 max test,) the pulmonary ventilation initially increase proportional to the increase in workload
-at some point (65-85% VO2 max), the ventilation rate increases rapidly, and this point is the ventilatory threshold
What is the lactate threshold?
- The blood lactate remains low (about 1 mmol/L) initially initially and as the exercise continues
- Lactate threshold is the point where the blood lactate start building up exponentially and reach OBLA (onset blood lactate level, 4 mmol/L)
- Lactate threshold is closely related to the ventilatory threshold
what is the OBLA
a specific level of blood lactate (4 mmol/L), is reached soon after the lactate threshold. This can be altered with training
what is the oxygen deficit
- oxygen deficit is the difference between the oxygen required to perform a task and the oxygen actually consumed prior to reach a steady state (where the energy demands and production are balanced)
- during this time, the energy is derived from anaerobic systems
What is the oxygen debt (EPOC)
- EPOC is the additional O2 taken in during recovery period in order to restore the energy balance
-helps re-establish CHO stores through resynthesizing 80% of the lactic acid back to glycogen in the liver
-helps catabolize rest of lactic acid through kreb cycle - helps restore ATP and CP stores in muscle
-helps reload myoglobin with O2
