Lecture 20 - Integration II Flashcards
What are the necessary factors in oxidative phosphorylation?
Oxygen consumption and carbon dioxide production are necessary factors in oxidative phosphorylation.
What is the Respiratory Exchange Ratio (RER)?
Ratio between oxygen consumption and CO2 production
RER= VCO2/VO2
Why is more oxygen needed for fat than glucose during metabolism?
More oxygen is needed proportional to amount of carbon, so more oxygen needed for fat than glucose.
What does the amount of oxygen used during metabolism depend on?
The amount of oxygen used during metabolism depends on the type of fuel being oxidized.
What can RER inform us?
What type of fuel is being oxidized.
if close to 1, glucose is the major fuel source or if less than 1.0, fats are the major fuel source
When is anaerobic production of ATP utilised?
For when we do not have enough time to utilise aerobic production of ATP - quick sprints or explosive efforts
What is anaerobic ATP production?
Anaerobic - producing ATP with absence of oxygen
Where do we get ATP from (no oxygen)?
We get ATP from fuel stores of creatine phosphate and glycogen
When is ATP GENERATION Phosphocreatine pathway used?
During anaerobic exercise - no O2 in pathway
~3-15 secs maximal exercise
What is the ATP GENERATION Phosphocreatine pathway?
When ATP is used by ATPase,
the ADP and Pi can be recycled to make more ATP from PCr
PCr can recycle ATP during
exercise until used up.
• Yields 1 ATP for each PCr
• ~3-15 secs maximal exercise
Where are our phosphocreatine stores?
In musculoskeletal cells
When is ATP GENERATION Glycolysis pathway used?
Anaerobic- no oxygen required
~15s to 2 mins
What is the ATP GENERATION Glycolysis pathway?
Glucose is converted to pyruvate which generates 2 ATP
What are our sources of ATP generation
Phosphocreatine
Glycolysis
Oxidative (from either CHS or fats)
Describe protein as a fuel source
Rarely used as a substrate
• starvation
• can be converted to glucose
(gluconeogenesis)
• can be converted to acetyl-CoA
Energy yield not easy to determine
2-5% of fuel source
At lower speeds, what is utilised for energy production?
At lower speeds both trained and untrained - utilise fats for ATP production
What is utilised for ATP production as excerise intensity increase?
Fats change to carbohydrate and anaerobic pathways
How does the utilisation of ATP production during exercise in trained people compare to that of untrained people?
As intensity increases, trained person can increase utilising only fats up until a much higher speed (change to carbohydrate and anaerobic pathways much higher speeds)
Besides VO2max, what is another important parameter for athlete’s?
Threshold intensity (aka lactate threshold, functional threshold power, FTP)
What is threshold intensity?
Maximal intensity that can be sustained for a prolonged period
What defines threshold intensity?
The threshold intensity or lactate threshold is defined as the point at which blood lactate begins to substantially accumulate above resting concentrations during exercise of increasing intensity (aka as glycolysis or anaerobic production of ATP begins to dominate).
In trained athletes, what can lactic acid as a fuel source be used for?
Trained athlete can use lactic acid as a fuel source for the brain, liver, and skeletal muscle.
What is lactate threshold?
Lactate threshold is balance between anaerobic glycolysis and clearance of lactate.
At exercise speed increases, and power output increases, there is a point where blood lactate first appears to increase disproportionally above resting values
How can lactate threshold increase over time?
Training between aerobic and lactate threshold is trains the body to use that lactic acid and to increase enzymes to break it down (so it can’t accumulate as fast) - this will increase lactate threshold overtime
What happens when we pass the lactate threshold?
When we pass the lactate threshold, there will also be a exponential increase in VE and VCO2. Lactic acid gets buffered by bicarbonate (increase H+ and CO2) which stimulates increase in VE and VCO2
VCO2 more than VO2 since switching to anaerobic.
Heart rate linear - increase heartrate, increase intensity
What is lactate threshold expressed as?
Expressed as a % of maximal oxygen
uptake (%VO2max).
What does lactate threshold represent?
Represents the fastest pace that can be tolerated during a long term endurance event. Perform at higher %VO2max reflects a higher lactate threshold.
What is Post-exercise oxygen consumption (EPOC)?
The oxygen uptake needed to balance the oxygen debt created after exercise
Why do we have EPOC?
When exercise begins, the oxygen transport system does not immediately supply the needed quantities of oxygen to the active muscles.
It takes several minutes to reach the required level at which aerobic processes are fully functional.
Why does it take several minutes after exercise for oxygen consumption to reach rest levels?
Because it takes a while to oxygen to catch up to required level.
Why is oxygen needed post exercise?
Oxygen is needed to restore ATP and PCr levels but also to combust the lactate.
How is cardiac output determined? (equation)
Q = HR x SV
What is avg cardiac output at rest?
Resting CO=5L/min
What is avg cardiac output during exercise for trained and untrained?
Untrained CO=20L/min
Trained CO=40L/min
What is the relationship between HR and increasing exercise intensity?
As intensity of exercise increases, HR increases proportionately.
How do we measure HR?
Pulse
What is maximum HR?
The maximum HR is the highest HR value
achieved in an all-out effect to the point of
volitional fatigue.
HRmax is a highly reliable value that remains constant day to day.
Decreases each year with gradual decline with age.
How can we estimate HR based off age?
A more accurate equation to estimate HR from
age is:
HRmax= 208- (0.7 X age).
What is steady-state HR?
When exercise is held constant at any submaximal workload, HR increases rapidly but then reaches a plateau. The plateau is steady-state. This HR is what is needed to provide the oxygenated blood to the muscle bed for the level of activity of the muscle.
• If intensity increases, so does steady-state HR
• Adjustment to new intensity takes 2 to 3 min, however as the intensity gets stronger, it takes longer.
Why can there be a difference in HR between two people doing the same level of work?
The individual with better endurance capacity because can extract more oxygen (e.g. more mitochondria in muscles) and so does not have to increase HR to the same level of intensity
Why is HR the bigger variable in cardiac output (Q)?
Because HR can continual increase whilst SV reaches a max and then stays constant (can’t increase further)
