Exercise phys UNIt 2A

J.Fisher SLU

Direct calorimetry assesses energy expenditure through measurement of

heat
Indirect calorimetry assesses energy expenditure through measurement of

O2 consumption
The Haldane transformation allows calculation of the volume of air inspired from measured values of

all of the above (volume of air expired, CO2 and O2 content of expired air, nitrogen percentage of expired air calculated from CO2 and O2 content of expired air)
The amount of protein oxidation can be estimated from measures of

urea production
The nonprotein RER for oxidation of carbohydrate as the sole fuel is about

1.0
The nonprotein RER for oxidation of fat as the sole fuel is about

0.7
The RER for oxidation of protein is about

0.818
An RER of about 1.0 would occur in

high intensity aerobic exercise (e.g. about 90% of VO2max or higher)
RER can be greater than 1.0 when

a drop in blood pH causes CO2 to be released in excess of the metabolic VCO2 of the tissues
RER can be lower than 0.7 when

blood bicarbonate is being replenished from CO2 produced by the tissues, resulting in less CO2 expired than is produced by the tissues
Which is a better measure of aerobic exercise workload?

VO2
When the carbonic anhydrase reaction is replenishing blood bicarbonate after exercise, VCO2 measured at the breath is actual tissue CO2 production.

lower than
When blood pH goes down, VCO2 measured at the breath is actual tissue CO2 production.

greater than
When a person breathes in oxygen from a container, and the exhaled oxygen goes back to that container during a procedure to measure oxygen consumption, that’s

closed circuit spirometry
In open-circuit spirometry, the procedure generally includes these EXCEPT

direct measure of volume of inspired air
Which is the most direct measure of metabolic energy expenditure?

direct heat measurement
In open-circuit spirometry, when is V_E equal to V_I?

when VCO2=VO2
In open circuit spirometry, which of these is calculated from measures of the other two?

% N₂ in exhaled air
In closed-circuit spirometry, which gas needs to be absorbed so that it does not build up in the gas in the breathing chamber?

CO₂
Closed circuit spirometry as shown in the diagram measures

Oxygen consumption
In a VO2max test, does the equipment measure the CO2 and O2 in the room air?

no, the fractions of CO2 and O2 in ambient air are known, so these do not need to be measured
Is the volume of inspired air directly measured at the air intake side?

no, this can be back-calculated from the volume of expired air and the fractions of O2 and CO2 in the expired air
Are oxygen consumption and CO2 production always the same?

no, these vary by the oxidative substrate (e.g. fat vs. carbohydrate)
When RER is 1.0

carbohydrate is essentially the only oxidative fuel
What is inspired V_E x % O₂ in the inspired air minus expired V_E x % O₂ in expired air?

VO2
As aerobic workload increases, RER

increases
A metabolic equivalent (1 MET) is

both of the above (VO2 of 3.5 ml/kg/min and resting metabolic rate)
For an exercise like running, in which a person needs to carry their own body mass, VO2 is best expressed as

ml/kg/min
For an exercise like cycling on a flat course, total power is more important to power relative to body mass. For cycling on a flat course, VO2 is best expressed as

liters/min
For folks in their 70's, lower VO2max is

related to higher risk of dying
Based on the chart, Curtis (the 35-year-old featured in the VO2max testing videos) had a VO2 max

about the 60th percentile for men his age
A 26-year-old woman who has a VO2max of about 72 ml/kg/min is

off the VO2max charts, regardless of age or sex
Any racing exercise event lasting more than 5 minutes is predominantly

aerobic
A person is doing an exercise ramp where workload increases but VO2 no longer increases. This is most likely to be the point of

VO2max
Aerobic training adaptations that increase VO2max include all EXCEPT

increased maximal heart rate
What aspect of VO2max can not be improved by aerobic training?

maximal heart rate
In relative terms, men and women are closer together in VO2max values when VO2 is expressed

as liters/min
Which of these athletes would have the highest VO2max values (ml/kg/min), because they employ a large amount of muscle mass and are aerobically trained?

cross country skiers
Performance in an event like rowing depends on absolute power output, and body mass makes minimal impact on the drag of the boat. For this event, VO2 is best expressed as

liters/min
Who has higher VO2max? (active vs. sedentary males)

active males
Who has higher VO2max? (42-year-old vs. 62-year-old active males)

42-year-old active males
When VO2 is plotted against heart rate for submaximal aerobic exercise and then the line is extrapolated to estimated maximal heart rate, this allows determination of

VO2max
Why might someone want to predict VO2max instead of measure it?

all of the above and probably a slew more reasons
Starting from the 20s, VO2max (on average)

decreases with age
Factors underlying a decline in VO2max (ml/kg/min) with age include all EXCEPT

less brain activity
The “immediate energy system” that is dominant in brief, maximal events (e.g. 6 seconds) is the

creatine kinase reaction
The “short-term energy system” that is dominant in maximal events lasting about 30 seconds to 2 minutes is

glycolysis with lactate production
The “long-term energy system” that becomes predominant in events lasting longer than about 2 minutes is

aerobic metabolism
In a maximal event lasting a couple of minutes, which systems contribute to total ATP production?

all of the above (creatine kinase reaction, glycolysis with lactate production, aerobic metabolism)
The contribution of phosphocreatine to ATP production (in terms of total ATP)…

is the same in 10 second, 30 second, and 90 second maximal efforts
The contribution of phosphocreatine to ATP production (in terms of percent contribution to overall ATP production)…

decreases as event duration increases
As exercise intensity increases from 30% of VO2max to 150% of VO2max, use of glycogen

increases
Which is the main means for ATP production in a maximal exercise effort lasting about 4-6 seconds?

the creatine kinase reaction
In a 60 second maximal exercise effort, which ATP-regenerating systems contribute?

all of the above (creatine kinase reaction, glycolysis, aerobic ATP production)
In an event lasting more than 90 seconds, there will be an even greater reliance on

aerobic metabolism
In the middle of a 60 minute race, a cyclist most relies on the ___ energy system.

long term (aerobic metabolism)
Which is the component of total daily energy expenditure that a person can change from day to day and make a substantial impact?

physical activity
Which is the largest component of total daily energy expenditure for someone who is not doing an enormous volume of aerobic activity?

basal metabolic rate
What happens to basal metabolic rate with aging?

declines with age
One likely explanation for women having a slightly lower basal metabolic rate than men per unit of body surface area is that…

women on average have a bit less fat-free mass than men
When resting metabolic rate (y-axis) is plotted against fat-free mass (x-axis)…

the points for women and men all fall along the same line
Heart rate and VO2 are

approximately linearly related
Which is LEAST related to basal metabolic rate?

sex
A runner who is more economical than another…

has a lower VO2 at a given speed compared to the other runner
VO2 is related to speed and body mass for

both of the above (walking and running)
VO2 is lowest for

downhill walking
Running velocity is dependent on

both of the above (stride frequency and stride length)
Swimming economy is by training and in cold water that causes shivering.

improved: decreased
Peak fat oxidation (g/min) occurs somewhere near

the lactate threshold
Although the percentage contribution of fat to total oxidative fuel goes down as aerobic exercise intensity increases, the absolute fat oxidation (g/min) has an inverted U shape, because…

energy expenditure (kcal/min) goes up with increasing exercise intensity, and this total energy expenditure times the fraction of fat use gives the fat use in g/min
If someone is running at a comfortable running speed but then switches to walking at the same speed, VO2…

goes down
VO2 for running on a treadmill is to VO2 for running on a track because .

similar: in the range of distance running speeds, air resistance doesn’t change much
One way to improve swimming economy is to

do lots of swim training
If two runners are equal in all factors except running economy, the one with the greater economy

is faster
The relation between walking speed and VO2 is fairly linear for

moderate velocity
A stair sprint can be used to measure power because it involves

all of the above (power = force x distance / time)
A team of distance runners performed a workout at 110% of VO2max for a total of 15 minutes at this pace. How were they able to accomplish this?

splitting the total of 15 minutes into 2-3 minute chunks at 110% of VO2max with rest in between
Air resistance most hinders performance for competitive races in

cycling
Given these relations between the cost of transport (COT), a person's preferred walking speed (with lowest oxygen cost) is at

B (the lowest point on the walking COT curve)
All might be factors explaining these sex differences in aerobic power EXCEPT

men don't have a decline in VO2max with agin