WEEK 3 Flashcards
Length of time in moderate intensity zone
Steady state for hours
Metabolism in moderate intensity zone
-ATP outflow matched w aerobic ATP inflow
-High reliance on fats, still relies on carbs
-Low ADP, H+ and Pi, high glycogen
What type of race falls under the moderate intensity zone?
Marathon (zone 2)
Length of time in heavy intensity zone
Steady state for 1 hour
Metabolism in heavy intensity zone
-Increased reliance on CHO metabolism (the higher the intensity, the more you rely on CHO)
-Increased ADP, H+ and Pi+, reduced glycogen
-ATP demand matched by aerobic inflow but its harder
What races fall under heavy intensity zone?
5k and 10k
Length of time in severe intensity zone
Non steady state, few min
Metabolism in severe intensity zone
-Mismatch btwn ATP demand and aerobic inflow
-Increased ADP= more anaerobic glycolysis and therefore more fatigue inducing metabolites such as H+ and Pi+, further reduction in glycogen
What length of race falls under severe intensity zone?
1500m
What length of race occurs in extreme intensity domain?
100-800m
Why does HR decrease during ultra endurance running events?
- Power output decreased, Vo2 decreased (they are tightly coupled), lower CO required to match that VO2
OR - SV is increasing while VO2 and CO stay the same
What is cardiac output tightly coupled to?
Vo2
As we increase VO2, CO increases linearly and so does HR
Why do people get slower in ultra running events?
- Muscle damage and fatigue
- Glycogen depletion
Glycogen depletion at high intensities
Rapid glycogen depletion, can only perform for a short duration
Glycogen depletion at low intensity exercise
Slower rates of glycogen depletion and can sustain this much longer
What happens when we deplete our glycogen stores?
Fatigue
Rely more on oxidation of fats but fats provide a limited amount of energy
What is the key determinant of fatigue at exercise durations greater than 60 min?
Glycogen depletion
How does ingestion of carbs during exercise improve performance?
Prevents glycogen depletion
**exercise intensity matters
Previous recommendation of carbohydrate ingestion
60-90 g carbs/hour of exercise
Carb drinks such as gatorade (bloating and GI discomfort)
Current recommendations for carbohydrate ingestion - FUELING REVOLUTION
130+ g carbs/hour
Gels (easier to consume)
Drafting
Surrounding one cyclist who the team wants to win with other cyclists during the race to break the air resistance so it requires less effort to cycle for most of the race
Burning matches
Every time a cyclist puts in a high effort “burning a match” which depletes glycogen and makes it harder throughout the race to replenish muscle glycogen
Final effort
- During the final climb cyclists enter severe intensity domain when they stand and accelerate
- Mismatched ATP outflow and aerobic ATP inflow
- Leads to glycogen depletion and burning matches
How can burning a match effect the next day?
Progressive decline in muscle glycogen as cyclists keep burning matches which affects future races
David Roche training style
Rather than testing and training an endurance athlete’s LT to determine performance, he only works to train Vo2 max bc if you can increase Vo2 max, everything else will also increase (LT and CP)
Trained to improve 5k
What is meant by “be aggressively open minded and curious”?
David Roche provides an anomaly, and these anomalies are what lead to revolutions
Where does gas exchange between the air and blood occur?
Alveolar air sacs
What is the efficiency of gas exchange dependent on?
Ventilation
Respiratory exchange ratio (RER)
Ratio between VCO2 and VO2
What does a RER value of less than 1 indicate?
Aerobic metabolism is involved
*CO2 production equal to or less than O2
What does a RER value of greater than 1 indicate?
Anaerobic metabolism is involved.
Respiratory quotient (RQ)
The ratio of carbon dioxide produced to oxygen consumed by the cells each minute
RER provides a good estimate of RQ
Tidal volume
Volume of air drawn into and expired out of lungs during a respiratory cycle
How does arterial gas composition change during exercise?
It doesn’t; it remains constant
What components of ventilation increase during exercise?
Tidal volume, respiratory rate
O2 and CO2 production
What state must you be exercising in to use oxygen consumption as a measure of overall metabolic rate?
During steady state exercise in moderate and heavy intensity domains
How can we estimate the energetic cost of aerobically sustainable activities?
Determine rate of oxygen consumption
Which two factors affect the concentration of exhaled gases?
- Metabolic demand of the active tissues
- Flow of respiratory medium over respiratory surface
What happens to oxygen as energy yielding molecules such as carbs and fats are metabolized to produce ATP?
Oxygen consumption increases
How can the rate of oxygen consumption and carbon dioxide production be measured?
Spirometry and gas analysis techniques
Indirect calorimetry
RER can provide an indication of the predominant substrate being metabolized during exercise
Direct calorimetry
Enclosing an organism inside a thermally insulated chamber and monitoring the temperature rise inside (hard to do)
Is the amount of heat released related to the amount of O2 consumed in aerobic respiration?
Yes
What two assumptions must be accurate for the amount of heat released to be related to O2 consumed?
- Organism must be using aerobic respiration only
- Current oxygen uptake must exactly balance current need for aerobic respiration
Breathing frequency (f) in normal ventilation
15 respiratory cycles per min
VE
Expired minute volume; amount of air exhaled in one min of breathing
How to calculate VE
VE= f x TV (tidal volume)
What factors contribute to increasing tidal volume and respiratory rate during exercise?
- Increased central nervous drive
- Changes in arterial blood pH
- Potassium conc
- Alterations in sensitivity of carotid bodies to CO2
How to calculate theoretical max HR?
220-age
How to calculate rate of oxygen consumption (assuming an RQ of 1)
VO2= VI(FIO2-FEO2)
How to calculate rate of CO2 production (assuming an RQ of 1)
VCO2= VI x FECO2
What happens to blood flow to exercising muscle as intensity increases?
Dilation of arterioles = increased blood flow
Synpatholysis
Ability of blood vessels in skeletal muscle to counteract vasoconstrictive effects of sympathetic NS and allows blood flow to active muscle to be maintained
What should your HR stay below to ensure you’re exercising in an aerobic steady state condition?
Don’t go above 75% of max HR
At higher intensities what can we not say when measuring oxygen consumption?
Cannot claim that the metabolic rate calculated from oxygen consumption represents total metabolic rate bc we are using anaerobic metabolism
RER won’t = RQ
