PHYL2730 Lecture Notes - Lecture 5: Vo2 Max, Bicarbonate Buffer System, Lactate Threshold
Wednesday, 21 March, 2018
Week 5 Anaerobic Threshold
Theory behind (significant problem and limitation)
-deplete iron for 3 weeks to induce anaemia and run a VO2 max test in a seal
container with known amount of oxygen, run the mouse till fatigue; plus the TTF test to
estimate performance
-to estimate performance, Vo2 max test is not a good measurement; a better
measurement will be setting up ergometer at a certain speed and see how long they
can go TTF test
-low iron concentration reduce RBC counts which reduce O2 capacity which leads to
earlier fatigue since there is a decrease in O2 delivery to muscles
-re infusion of iron do not have effect on mitochondrial function; it shows improvement
of V02 max test but not change in TTF test thus O2 carrying capacity in blood
determines VO2 max but mitochondrial activity determines performance
-In elite athletes, they all have similar VO2 max so it is poor predictor of performance
-Vo2 max is a better predictor in performance in a mixture level of participants
-Vo2 max do not change much in adulthood but performance can change
-Ventilatory threshold and Lactate threshold are superimposable,
-Lactate threshold is more sensitive to training
-OBLA (Onset of blood Lactate accumulation) OPLA (Onset of Plasma Lactate
Accumulation) IAT (Individual Anaerobic threshold) VT (Ventilatory Threshold)
-The inflection point shift to the right with training due to: more O2 delivery to muscle,
better extraction of O2 to muscle, buffering capacity is better as more negatively
charged protein buffer H+ so rate of accumulation of lactic acid reduce,
-blood saturation of O2 is about 100% no matter where we are (sea level or 3000m)
because our breathing rate is faster to compensate the altitude lower of O2
concentration; the increase of breathing rate is controlled by the disruption of
homeostasis which causes catecholamines to drive up the respiratory rate
-our ventilatory threshold creeps up because of the bicarbonate buffering system in
blood, H+ generated in muscles are buffered by negatively charged protein and are
travelled out to blood and buffered by HCO3-, HCO3- is regenerated by releasing Co2
from expiration
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Document Summary
Deplete iron for 3 weeks to induce anaemia and run a vo2 max test in a seal container with known amount of oxygen, run the mouse till fatigue; plus the ttf test to estimate performance. To estimate performance, vo2 max test is not a good measurement; a better measurement will be setting up ergometer at a certain speed and see how long they can go ttf test. Low iron concentration reduce rbc counts which reduce o2 capacity which leads to earlier fatigue since there is a decrease in o2 delivery to muscles. Re infusion of iron do not have effect on mitochondrial function; it shows improvement of v02 max test but not change in ttf test thus o2 carrying capacity in blood determines vo2 max but mitochondrial activity determines performance. In elite athletes, they all have similar vo2 max so it is poor predictor of performance. Vo2 max is a better predictor in performance in a mixture level of participants.
