L22 The Cardiorespiratory Response to Exercise Flashcards
Centre of Gravity of the Human Body
Falls at the Crest of the Ilium of a Lean male
- Centre of Gravity is Lower in woman than it is in men due to:
a) wider hips
b) tendency to put weight on there/
except: middle aged man who have a pronounced abdomen, have to lean backwards in order to keep their centre of gravity is Above their feet - if their centre of gravity isnt above their feet, then goes horizontal
Where is the centre of gravity in a foseberry flop in pole vaulting?
-
Increase in Ventilation from rest to exercise
V.O2 and V.CO2 can increase 20-30 fold from rest–> exercise
Fick principle with Ventilation
can measure ventilation using fick principle, measure O2 content at mouth and change of oxygen content around circulatory system
During steady state exercise
Same amount of oxygen being consumed be the cells
as is the net difference between what is coming in and going out again
-same for CO2 production
During Steady State exercise equations
V.O2=V.(FIo2-FEo2)
=Q.(Cao2-Cv-o2) (CO find the difference between arterial and mixed venous contents of oxygen
Rate of oxygen consumption = rate at which it is disappearing at the mouth x rate at which it is disappearing out of the blood system
Steady state= Rate O2 disappearing through ventilation as same as rate disappearing through circulation
V.= VTidal x Freq
Q.=VStroke x Freq
During Steady State exercise equations with Quantitative values
Rest= Vtidal x Freqresp (FIo2-FeO2) = Vstroke x Freqresp (Cao2-Cv-o2)
REST: 240 = 0.5 x 12 x (0.21-0.17) = 70 x 20 x (200-150)
During Exercise equations with Quantitative values
Rest= Vtidal x Freqresp (FIo2-FeO2) = Vstroke x Freqresp (Cao2-Cv-o2)
V.O2max= 5000 = 0.5 x 12 x (0.21-0.17) = 70 x 20 x (200-150) = 5Lmin-1
Profound increase in amount of O2 extracted, and the consequent lowering in the content of oxygen in venous blood
Ratio = x20 = x4 x3.5 x1.5(minor change for the oxygen extracted at level of the lung) = x2 x3 x3.5
Rate of Metabolic Energy expenditure (V.O2) proportionality
Rate of Metabolic Energy expenditure (V.O2)
-attributing totally to O2 consumption. partially true as go into lactic acid producing stage during end of long race
Proportional to
Rate of Mechanical Work. -= Power (rate at which work is done)
Rate of Metabolic Energy expenditure (V.O2) proportionality graph
Oxygen consumption(Lmin-1) as a function of Power(watts) -Oxygen Uptake values obtained via sitting on bicycleodometer (mlkg-1min-1) Sedentary= 30 Normal active= 45 Conditioned=53 Endurance athletes=85 = cross country skiers (tall large chest body build)
Efficiency Graph
Invert Oxygen consumption(Lmin-1) as a function of Power(watts) graph to have Power vs Oxygen uptake = Efficiency
=400W/ ((6L/60s)x(20kj/L)) = 0.20 = 20% efficiency
How much energy does one L of oxygen provide?
60kJ
Increased work of breathin
Deeper breaths
More frequently
Work of breath graph
Increase rate of work
V.O2 Modest Rate of O2 consumption by respiratory =Resting, Walking slowly, Working quite quickly
V.O2 increased quickly= climbing stairs, sawing, running 12kmhr-1
-remains a small part of the total o2 consumption
-but a Disproportionate increase (3% –> 10%)
What is the cause of the disproportionate increase in the work of breathing?
-