Exercise physiology Flashcards
Which three system are involved in exercise and breathing - in which order?
Muscle
Heart and blood
Lungs
During aerobic respiration, why do you have to breathe out more?
More carbon dioxide is made and do more breathing to remove the carbon dioxide
How is the amount of CO2 made during lipid metabolism different to glucose metabolism?
During lipid metabolism, less CO2 is made per oxygen molecule (less breathing required so useful during ventilation of patients
What is the ratio of C02 production to O2 consumption called?
respiratory quotient (muscles) respiratory exchange quotient (mouth)
How is the amount of CO2 made during protein metabolism different to glucose metabolism?
Protein is more efficient than glucose (less CO2 made) but less than lipid
What is the theoretical maximum for RQ (glucose)?
1
What happens to RQ when anaerobic respiration occurs, and why?
RQ goes above one as oxygen consumption doesn’t increase but CO2 production does.
Seated at rest, how much oxygen does the average sized human require?
3.5ml/min/kg
Why does stroke volume decrease the faster the heart rate goes (beyond a certain point)?
The heart doesn’t have enough time to fill completely
Which two things must occur to increases oxygen consumption?
Cardiac output and more oxygen is extracted from the blood by the muscles
allow you to increase your oxygen consumption.
What is the equation for VO2 (oxygen consumption)?
VO2 = Cardiac output * (a-v) O2 content [means extraction]
How can a person who isn’t getting enough oxygen due to a muscle problem be identified?
mitochondrial disease - oxygen isn’t extracted
pulmonary artery catheter , during exercise the oxygen saturation is still high even if they are exercised (muscle problem)
What are two types of exercise?
Incremental exercise - increases in intensity
Steady state exercise - intensity maintained
Which two factors change in the lungs to increase oxygen entering the lungs?
breathing rate and tidal volume
Why do we only breathe at half the vital capacity?
It requires a lot more effort to use the full vital capacity
What causes effects like fainting due to hypoventilation?
pH goes up, fewer protons in blood and more calcium bind to albumin (which can also bind protons) so less calcium causes effects like fainting
How does VQ matching differ between at rest and during exercise?
At rest VQ matching isn’t ideal but during early exercise the VQ matching improves
At rest, where do most of the blood and air go to in the lungs and how does this change during exercise?
at rest most of the blood and air go to the bottom of the lung
Blood and air go all the way through the lungs during exercise.
What happens to ventilation rate as CO2 increases?
As carbon dioxide concentration increases so does ventilation rate. There is close coupling of VE to VCO2.
What is the Bohr effect?
The ODC shifts to the right during exercise as hemoglobin has less affinity for oxygen so more unloading.
What is the ventilatory compensation point?
At the end of exercise , HCO3- runs out and hyperventilation occurs - chemoreceptors detect this. No more exercise can occur.
During steady state exercise how does oxygen consumption change and why is there a time lag between increase in oxygen consumption and exercise?
Oxygen consumption increases and then stays stable. When oxygen is measured at the mouth, there is a time lag between exercise and increase in consumption due to the time it take to get from muscle to heart to the lungs.
What is oxygen deficit?
The amount of oxygen consumed isn’t enough to fulfill demand so anaerobic mechanisms begin.
What are the two main types of chemoreceptors?
peripheral chemoreceptors - aortic (detects carbon dioxide and O2 but not pH) and carotid bodies (detect all three)
central chemoreceptors - medulla
