Week 4 Flashcards
Why do we care about VO2max?
Higher VO2max= reduced risk of all-cause mortality
How does VO2 max predict performance?
General pop–> valuable indicator of performance (wide range of fitness levels)
Elite athletes–> All other variables determine performance
What is VO2max?
Measurement of the maximum rate of oxygen consumption by an individual using oxidative phosphorylation within the mitochondria
*best measurement of cardiorespiratory fitness
What is VO2 max maximal activity of?
Heart, lungs, circulation and diffusion of O2 into active tissue
VO2max- activity of heart
CO (LV pumping blood)
VO2max- activity of lungs
O2 diffusion into blood
VO2max- activity of circulation
O2 carrying capacity as determined by Hb conc
VO2max- activity of diffusion
Diffusion of O2 into active muscle–>CapD (K) and mito capacity (Plo)
How does training improve the factors leading to VO2max?
-Improved activity of heart (Increases CO)
-Improves O2 carrying capacity
-Improved CapD and mito capacity
Can training improve VO2 max?
Yes but there is a limit to how high we can push VO2max through training alone
What physiological change doesn’t occur with training?
No changes to lungs
How does David Roche suppose we can augment performance once we reach VO2 limit?
- sodium bicarbonate
- downhill running
- high-carb fuelling
- super shoes
- post-exercise exogenous ketones
- heat training
- caffeine
Types of doping
- Asthma medication
- Blood doping
Doping- asthma medication
Short-acting beta agonists (SABAs) help open airways (dilation of bronchioles to increase O2 diffusion into blood)
Impact of SABAs
Minimal impact on performance or VO2max in healthy athletes
Types of blood doping
- IV infusion
- EPO supplementation
Impact of blood doping
Very effective; Increases BV to increase CO and Hb to increase O2 carrying capacity
Relative energy deficiency syndrome (REDS)
-Overtraining
-Reduced performance and no training adaptations
-Sometimes not about the training but rather about fueling w nutrition
How can we measure VO2max?
Step test
–>Incremental test
–>RAMP test
Step test
Sequential steps of increasing intensity; allows to us to determine VO2max by seeing at which point there is an inability to increase VO2, despite increases in WR
Plateau in VO2
Despite increases in power output/WR, there are no further increases in VO2
Incremental test
Step test w no rest btwn increasing intensities
ie. bike and treadmill test
RAMP test
Constantly gradually increasing intensity
VO2 peak
Highest (peak) VO2 observed during an incremental/RAMP protocol; not necessarily the max, need another test to confirm
What would the minimum intensity be for a confirmation stage?
1 W above CP–> must be IN severe intensity domain
When is VO2 peak equal to VO2 max?
Almost always, but you can’t call it VO2 max unless you actually confirm it (confirmation stage )
How can you find VO2 max without directly testing it?
- Aerobic power
- Prediction equations
Example of an aerobic power test
Incremental treadmill test to see how long people last (time to fatigue)= aerobic power
Aerobic power
Highest power supported by aerobic metabolism
Can can be used to predict mortality risk
Correlates with VO2 max
Example of how a prediction equation can be developed
Measuring peak WR and corresponding VO2 to develop a prediction equation to estimate VO2 max
Prediction equation for VO2
VO2= 500(estimated resting VO2) + (WR (Watts) * 10mL/Watt)
Are prediction equations accurate?
There are inaccuracies when estimating using prediction equations but if you understand them you can still use the equations
WRpeak
Highest WR in RAMP or incremental test
Is WR max seen on an incremental test?
NO, its WRpeak
What does a higher WRpeak mean?
Longer time on treadmill= higher VO2 max
How can we determine performance?
WR (W)/ bodyweight (kg)
What terms are synonymous with VO2max?
Cardiorespiratory endurance, aerobic capacity, or cardiorespiratory fitness
Factors that influence a participant’s VO2max
- heredity
- sex
- age
- training status
- mode of exercise
Cardiopulmonary exercise test (CPET) each stage duration
1-3 min
What is a steady state in the CPET?
Point where aerobic metabolism contributes 100% of the energy requirement at a given absolute intensity
How long is total testing time for a CPET?
8-15min
Criteria to determine if VO2max has been met
- Vo2 plateaus (increases <150ml/min) despite an increase in WR
- HR during the last stage is no more than 10bpm below the participant’s age-predicted maximal heart rate
- Respiratory exchange ratio is greater then 1.1 in final work state
- Rating of perceived exertion is greater than 17 on Borg scale
How many of the criteria for VO2 max must be met?
2/4
Ventilatory threshold (VT)
The point where ventilation increases disproportionately to oxygen consumption
Pattern of VO2 during CPET
Linear function of power output up to VO2max
Pattern of ventilation during CPET
Linear only during exercise requiring approximately 55 –75% VO2 max and after this point, VE increases at a steeper rate
Between which domains does VT1 occur?
Moderate and heavy
Between which domains does VT2 occur?
Heavy and severe
Why does ventilation increase more steeply in the heavy- compared to moderate intensity domain
Increased anaerobic metabolism (glycogen usage)
Greater flux through PDH results in an increase in the VCO2/VO2 ratio
Why does ventilation increase even more steeply from heavy to severe intensity domain?
Further increases in VCO2 via bicarbonate buffering of H+ to CO2
RER in moderate intensity
0.8
RER in heavy intensity domain
0.9-1.0
CHO RER in severe intensity domain
> 1.0
FFA RER in severe intensity domain
0.7
How to calculate RER
VCO2/VO2
What happens to RER if VCO2 increases?
RER increases
What happens to RER if VO2 increases?
RER decreases
VO2 max prediction ACSM equation- running
VO2MAX= (0.2 x speed) + (0.9 x speed x functional grade%) + 3.5
VO2 max prediction ACSM equation- walking
VO2MAX= (0.1 x speed) + (1.8 x speed x functional grade%) + 3.5
VO2 max prediction FRIEND equation
VO2max= speed x (0.17 + fractional grade x 0.79) + 3.5
Units for VO2max
mL/kg/min
What does the ventilatory threshold indicate?
Abrupt increase in blood lactate and decrease in blood pH
Ventilation and ability to speak
Moderate–> can talk
Heavy–> out of breath
Severe–> cant talk
Factors that effect Vo2 max - heredity
25-50% is considered genetic
Factors that effect Vo2 max - sex
Male values 15-20% higher
Factors that effect Vo2 max - age
Declines 8% per decade from age 20 on
Factors that effect Vo2 max - training status
Possible 6-25% improvement with training
Factors that effect Vo2 max - mode of exercise
More muscle recruitment= greater VO2 max values
