Lab 5 - Exercise (Vo2 Max) Flashcards
What is the name of the bag that air was expired into?
Douglas bag
What is the douglas bag experiment used to measure?
Volume of expired gases
Percentage of O2
Percentage of Co2
What does the measurements from a douglas bag experiment allow us to calculate?
Ventilation, O2 consumption and CO2 production.
What was the total volume of expired air measured in?
L
What is the equation for working out ventilation in L.min-1?
Expired gas volume (L) divided by gas collection period (min)
What is used to calculate oxygen consumption?
Ventilation
Fractional concentration of O2 in inspired air
Fractional concentration of O2 in the expired air
Ventilation x (FiO2 - FEO2)
What is used to calculate carbon dioxide production?
Ventilation
Fractional concentration of CO2 in Expired air
Fractional concentration of CO2 in Inspired air
Ventilation x (FeCO2 - FiCO2)
How do you work out Max HR?
208 - (0.7 x age)
What is EPOC?
Excess Post Exercise Oxygen Consumption
Why is O2 consumption still high in recovery?
Due to EPOC
What is the difference between the two equations used to calculate oxygen consumption by the body?
(1) Looks at oxygen extraction from blood in the body (oxygen out of blood)
(2) Looks at oxygen extraction from air in the lungs (Oxygen into blood)
When our body is in balance/homeostasis what is the relationship between oxygen extraction from tissues vs lungs?
The are exactly the same
What is the RER?
Respiratory exchange ratio (or called the respirtaory quotent).
It is the ratio between oxygen production and oxygen consumption.
If R is 0.7 what does it mean?
That there is exclusively fatty acid oxidation
If R is 1.0 what does that mean?
That there is exclsuievly carbohydarte metabolism.
What causes the RER to exceed 1.0 during exercise?
Hyperventilation meaning that you are breathing out more CO2 than is being produced
Lactic acid production leads to excess H+ and then CO2
What is VO2max?
The maximum amount of oxygen the body can utilise.
What does our body use oxygen for?
To burn feul in order to produce energy = therefore the more oxygen your body can use, the more energy you can produce.
What do people with higher VO2max have lower risk of?
Premature death, cardiovascular disease, chronic conditions such as Type 2 diabetes.
What is the highest male and female Vo2max ever recorded?
Male = Oskar S cyclist @ 97.5
Female = Joan B runner @ 78.6
What is the lowest resting HR ever recorded?
Daniel Green aged 81 @ 26 bpm
What is normal VO2max for male and female?
Male normal is 40-45
Female normla is 30-35
If you have a high Vo2max how is oxygen consumption and supply affected?
With a higher Vo2max you can take more oxygen out of each L of blood with increased blood supply due to increased HR.
At rest how is MABP mainatained within a small range?
Baroreceptor reflex
- baroreceptors in arteries detect BP changes and send signals to the brainstem.
The brainstem then adjusts the blance between the two nervous systems.
PSNS (resting state) = lowers HR, SV and TPR which all reduce MABP.
SNS (active state) = increases HR, SV and TPR increasing MABP.
How is the baroreceptor reflex adjusted during exercise?
During exercise your muscles need more oxygen so we need to allow an increase in MABP.
Therefore a central comand sends a signal to inhibt the baroreceptove cells so that there is no baroreceptor input.
Instead skeletal muscle contraction activates exercise pressor relex which causes an increase in sympathetic nerve activity.
= Increase in MABP.
Other than increase CO how else can the vascular system increase O2 delviery to active muscles?
Vasodilation (which decreases TPR)
What is the effect of vasodilation on TPR?
Decreases it
How does vasodilation occur?
Functional sympatholysis and B-adrenergic receptors
What is functional sympatholysis?
Functional sympatholysis refers to the ability of the active muscles to override the normal vasoconstriction caused by sympathetic nerve activity. This is achieved through local factors in the skeletal muscles, like the release of nitric oxide (NO), CO2, H+ and adenosine and the decrease in O2 which cause vasodilation.
This selective “relaxation” of blood vessels in the active muscles helps direct more blood to them while allowing the rest of the body’s blood vessels to stay constricted to maintain overall blood pressure.
Does EPO injecting change oxygen requirements at rest?
No
What are adverse effects of an increased haematocrit ratio?
Increase blood viscosity (thickness of blood) therefore there is an increased risk of coagulation (clotting) and more work for the heart.
When is an athlete who EPO injects at greatest risk?
The night after a big event - ebcause dehydrated and low resting HR when sleeping (= very thick and slow moving blood)
