LAB3- VO2max Testing Flashcards
what does VO2 max testing measure
the maximal amount of oxygen the body uses while exercising at maximal levels
what is the most valid + accurate way to assess cardiorespiratory fitness
VO2 max testing
VO2 max definition
an increase in workload (intensity) and no increase in oxygen consumption (a plateau)
Q stands for
cardiac output
a-VO2 difference
arteriovenous oxygen difference
-the difference in oxygen content between arterial + venous blood
-measure of how much oxygen is removed from the blood as it passes through the body’s capillaries
what equation determines VO2
Fick principle
**Fick principle
(be able to recite)
VO2 = Q x a-VO2 difference
who created Fick principle
Adolf Fick
-1870
what does Fick principle do
theoretically calculates total body oxygen consumption
-can also help explain adaptations to cardiovascular exercise
central component of VO2
cardiac output
peripheral component of VO2
a-VO2 difference (arteriovenous difference)
cardiac output equation
Q = HR x SV
heart rate
the rate of heart contractions per minute
does maximal heart rate change with chronic cardiovascular training
no
most of the population variation in VO2 max is due to what
differences in stroke volume
-it is estimated that 70-85% of limitation in VO2 max is due to maximal stroke volume
stroke volume
the amount of blood ejected by the heart with each contraction
is stroke volume influenced by cardiovascular training
yes, HEAVILY influenced
arteriovenous difference
a measure of the amount of oxygen that is extracted from the blood by the tissues
what is arteriovenous difference influenced by
-capillary density surrounding muscle
-skeletal muscle mitochondrial density
-skeletal muscle mitochondria function
-myoglobin content in skeletal muscle
adaptations following aerobic endurance training
(in order from greatest change to least)
-aerobic enzymes
-oxidative potential of FT fibers
-glycogen
-capillary density
-VO2 max
-cross-sectional area of ST fibers
factors that can influence components of VO2 max
-genetics
-age
-gender
-body composition (body fat %)
-training
what is the biggest determinant of VO2 max
genetics
factors that can influence components of VO2 max
which factors are uncontrollable
-age
-height
-gender
factors that can influence components of VO2 max
which factors are controllable
body composition + training
factors that can influence components of VO2 max
what % of variance in VO2 max values is accounted for by genetics
25-50%
factors that can influence components of VO2 max
genetics
individual genetic makeup predetermines a range of VO2 max values
-everyone has a CEILING set by genetics that is uncontrollable no matter what
-you could follow the same steps as someone else + still not be as good as them
factors that can influence components of VO2 max
what age does VO2 max peak
15-20
factors that can influence components of VO2 max
what % decrease in VO2 max per decade from age
8-10%
factors that can influence components of VO2 max
gender differences
males have 15-20% greater VO2 max than females
factors that can influence components of VO2 max
other gender factors into VO2 max
-women are predisposed to more fat
-men die earlier
factors that can influence components of VO2 max
by what % does training improve VO2 max
5-25%
-predominantly from imrpovements in stroke volume
factors that can influence components of VO2 max
training improves VO2 max predominantly from improvements in what
stroke volume
what is increased cardiovascular fitness associated with
decreased risk of disease + all-cause mortality
in seniors, what is maximal aerobic power related to
the functional independence of seniors in the execution of their activities of daily living
what athlete performance is heavily dependent on VO2
endurance athletes (distance runners, swimmers, cyclist, rowers, etc.)
VO2 is subjective/objective
objective
-tells us where we are at in our training + based on where we are at, we can adapt from there
main reasons for VO2
-training (we have a goal, see where we stand, + where to improve)
-health (disease prevention)
we are more inclined to run VO2 test on younger/older people
older people
-because older people are declining + therefore more disposed to disease
how many ways can VO2 be reported
2
-absolute or relative
2 types of VO2
-absolute VO2
-relative VO2
what do we need to convert between absolute + relative VO2
BW of the client
absolute VO2
directly related to body size
units of absolute VO2
L/min
-or mL/min
without knowing BW, can cardiovascular fitness be assessed using absolute VO2
no
what is absolute VO2 used to express
energy expenditure in weight-bearing or non-weight-bearing exercises
relative VO2
used to compare across individuals
-accounts for BW, which helps compare amongst a population
units of relative VO2
mL/kg/min
what is relative VO2 used to express
energy expenditure in weight-bearing exercises
is it common that we actively record a VO2 max on a client
RARE
-because of extreme effort that is required to hit an actual VO2 max
what is measured during a VO2 max test, regardless of whether or not a plateau was reached
highest rate of oxygen consumption measured during the test
if you don’t hit a VO2 max, what do you hit
VO2 peak
main difference between max + peak
in a max, you hit plateau
is VO2 peak a valid index of VO2 max
for some
VO2 peak shortcoming
does not clearly indicate the level of performance an athlete/participant is capable of reaching
is VO2 peak as good of a baseline assessment for exercise prescription as a VO2 max
not as good
-since it is not very reproducible
**indices of attained VO2 max (5)
-plateau in VO2 (less than 150 mL/min) with an increase in work
-HR plateau
-RER of 1.15 or more
-venous lactate concentration of 8 mmol/L or more
-RPE of 17 or more on Borg scale
which indice of attained VO2 max is the gold standard
plateau in VO2 (less than 150 mL/min) with an increase in work
**indices of attained VO2 max- plateau criteria
VO2 decreases by 150 mL/min
**indices of attained VO2 max- RER criteria
RER = 1.15 or more
**indices of attained VO2 max- venous lactate concentration criteria
8 mmol/L or more
**indices of attained VO2 max- RPE criteria
17 or more on Borg scale
if plateau in VO2 isn’t met on VO2 max, what is the requirement to be considered a valid VO2 max
if VO2 plateau isn’t met, AT LEAST 2 of the other indices must be met
RER stands for
respiratory exchange ratio
RER
how much air you are exhaling vs inhaling
RER ratio
CO2 / O2
-(exhale / inhale)
how do we expect RER to change throughout test
-in beginning of test, we expect ratio to be less than 1 because more O2 in than CO2 out (most people are around 0.6-0.8 in beginning)
-towards end, more CO2 out than O2 in
why is Borg 6-20
becaused based off 20 year old HR (6-100)
-SO if HR is about 70, they should be feeling around a 7
uses for Borg vs modified Borg
-Borg is for healthy, younger people (virtually everyone except for older populations)
-modified Borg used for older populations
what is a biohazard for venous lactate concentration
carpet
what are the most valid + accurate way used to assess VO2 max
maximal exercise test protocols
what can maximal protocols be used to estimate
VO2 max
-or in conjuction with the collection of respiratory gases (open or closed-circuit spirometry) to measure VO2 max
most of the protocols in regular use are what
graded exercise tests (GXTs)
what do maximal GXTs use
progressive increases in workload until no more can be tolerated by the body
what is the most common mode of exercise used for GXTs
treadmill
most common maximal treadmill GXT protocols
-Bruce protocol
-Astrand protocol
-Balke protocol
-Naughton protocol
-Ellestad protocol
-Cornell protocol
what protocol are we using in this class
Bruce
Robert A. Bruce
developed a protocol for increasing speed + grade on a motorized treadmill to test the cardiovascular system
Robert Bruce analogy to car
-he wanted to test cardiac patients’ hearts + likened it to buying a used caar
-he said you wouldn’t buy a used car without testing the engine first
what did Robert Bruce do in 1963
released a scientific paper that detailed a multi-stage GXT that would become known as the Bruce protocol
what is Bruce protocol considered gold standard for
detecting myocardial ischemia when used in combination with ECG
is Bruce protocol the best protocol for athletes particularly runners
no
-because it often causes localized muscular fatigue before the subject reaches maximal oxygen consumption
Bruce protocol- duration of each stage
3 minutes
Bruce protocol- beginning workload
1.7 mph
10% grade
grade
incline
Bruce protocol- ideal population
young + fit individuals
-however often used in older adults that need diagnostic testing when a physician is present
drawbacks of Bruce protocol
no plateau in VO2 commonly seen
**Bruce protocol- stage 1
(duration, speed, grade)
min 0-3
1.7 mph
10% grade
**Bruce protocol- stage 2
(duration, speed, grade)
min 3-6
2.5 mph
12% grade
**Bruce protocol- stage 3
(duration, speed, grade)
min 6-9
3.4 mph
14% grade
**Bruce protocol- stage 4
(duration, speed, grade)
min 9-12
4.2 mph
16% grade
**Bruce protocol- stage 5
(duration, speed, grade)
min 12-15
5 mph
18% grade
**Bruce protocol- stage 6
(duration, speed, grade)
15-18
5.5 mph
20% grade
**Bruce protocol- stage 7
(duration, speed, grade)
min 18-21
6 mph
22% grade
**Bruce protocol- recovery stage
(duration, speed, grade)
0-3 min long
2.5 mph
0% grade
what does the Bruce protocol have to estimate VO2
estmination equations
-like many popular maximal protocols
is there greater accuracy with actual VO2 measurement with spirometry or estimating
actual measurement
-however, if the equipment isn’t available to perform spirometry performing a maximal test, estimating will result in a more accurate VO2 than a submaximal test
what are VO2 max estimation equations based off of
research data for a specific population that was used to create a linear regression
open vs closed-circuit spirometry
-open: getting air from outside sources
-closed: getting air from a reserve, closed source
why is closed-circuit spirometry better
we know exactly what they are breathing; don’t have to account for humidity, more controllable
in our lab, what type of spirometry will be used
open-circuit
what does open-circuit spirometry measure
changes in oxygen + carbon dioxide % in expired air relative to the composition of ambient air
-can calculate oxygen consumption
open or closed-circuit spirometry is more common
open
our lab uses what machine for spirometry
Parvo Medics TrueOne 2400
(metabolic cart)
parts of metabolic cart (Parvo Medics TrueOne 2400)
(collective force, need all these pieces to work)
-breathing tube
-mixing chamber
-pressure tubes
-measurement module
-pneumotach
-air intake
describe how the metabolic cart works
air enters the tube from the right side of the mask into the breathing tube (open-circuit) ->
air goes through penumotach; there is a pressure + flow gauge on each side which allows us to measure the volume of air ->
the air enters a mixing chamber because at the beginning of expiration, composition is higher in O2 + lower in CO2 than at the end of expiration; thus, it needs to be mixed ->
a sampling line goes from the mixing chamber to the measurement module which has individual analyzers for O2 + CO2
what is whole body VO2 determined from
cardiovascular or respiratory measurements
2 equations to determine VO2
-Fick equation (VO2 = CO x aVO2 difference)
-VO2 = VIFIO2 - VEFEO2
VO2 = VIFIO2 - VEFEO2 coefficients stand for what
-I = inspired
-E = expired
-V = volume
-F = fraction
from the equation VO2 = VIFIO2 - VEFEO2, what values do we know
FIO2
from the equation VO2 = VIFIO2 - VEFEO2, what values do we measure
-VE
-FEO2
-FECO2
from the equation VO2 = VIFIO2 - VEFEO2, what values do we estimate
VI
from the equation VO2 = VIFIO2 - VEFEO2, which value is needed to estimate VI
FECO2
FIO2
fraction of oxygen in inspired air
FIO2 value
0.2095
FEO2
fraction of oxygen in expired air
FEO2 value
variable
what mask do we use
7450 Series Silicone V2 Oro-Nasal Mask with 5 Strap Adjustable Headgear
what valves do we use for mask
Hans Rudolph 2-way Non-Rebreathing valves
order of assembled valve for mask
-exhalation port tube
-stopper
-diaphragm
-support ring
-mouth port tube
-body
-diaphragm
-ring
-inhalation port tube
in order to have an accurate VO2 max test, what must we do to the Parvo Medics metabolic cart
calibrate to ensure accurate measurements are being recorded
what 2 values must be calibrated to ensure accurate measurements
-volume of air being received by the metabolic cart (volume calibration)
-composition of the air being received by the metabolic cart (gas calibration)
general GXT procedures
-prior to explaining the test, make sure all assistants helping with the test understand their role
-make sure the client has filled out all necessary forms (informed consent, PAR-Q, health-history questionnaire)
-review the test instructions with the client; let them know it is a maximal test, however they can stop whenever they want
-obtain resting values of HR + BP
-have the client straddle the treadmill, start the treadmill at the warmup speed, + have the client test the treadmill with 1 foot until they are comfortable with the speed + ready to start walking
how long do we have the client warmup for GXT
2-3 min
once the first stage has started, what values do we monitor throughout the test
-HR
-BP
-RPE
-physican appearance/symptoms
when do we discontinue the test
when termination criteria are met or client asks to stop
what do we have client do after termination of test
cool down, continue monitoring HR + BP
Gunnar Borg
developed the idea of perceived exertion scale in the late 1960’s + published a paper describing the scale in 1982
Borg scale
asks the client to rate how hard they’re working on a scale of 6-20, with 6 being no effort at all + 20 being all-out max
Borg scale was designed so that it could be compared to what
HR (an indicator of cardiovascular exertion)
what can we do if a client’s perceived exertion is largely equal to their measured cardiovascular exertion (HR)
RPE x 10 = (+/- bpm) of their HR
if a client’s perceived exertion is coming from another source other than cardiovascular exertion (HR)…
RPE x 10 will be much higher than their HR
if a client is perceiving the exertion that they are truly performing with their cardiovascular system
RPE x 10 will be much lower than their HR
Borg scale values
6- no exertion, sitting + resting
7- extremely light
8
9- very light
10
11- light
12
13- somewhat hard
14
15- hard
16
17- very hard
18
19- extremely hard
20- maximal exertion
general indications for stopping an exercise test
-onset of angina or angina-like symptoms
-drop in SBP of at least 10 mmHg with an increase in work rate or if SBP decreases below the value obtained in the same position prior to testing
-excessive rise in BP; SBP > 250 mmHg and/or DBP > 115 mmHg
-shortness of breath, wheezing, leg cramps, or claudication
-signs of poor perfusion: light-headedness, confusion, ataxis, pallor, cyanosis, nausea, or cold + clammy skin
-failure of HR to increase with increased exercise intensity
-noticeable change in heart rhythm by palpation or auscultation
-subject requests to stop
-physical or verbal manifestations of severe fatigue
-failure of the testing equipment
general indications for stopping an exercise test- drop in SBP
-drop in SBP of at least 10 mmHg with increase in work rate
-or if SBP decreases below the value obtained in same position prior to testing
general indications for stopping an exercise test- rise in BP
-SBP > 250 mmHg
-DBP > 115 mmHg
general indications for stopping an exercise test- signs of poor perfusion
-light-headedness
-confusion
-ataxia
-pallor
-cyanosis
-nausea
-cold + clammy skin
what client information + resting data is collected
-name
-age
-date
-height
-weight
-medications
-clinical history
-informed consent form signed (yes/no)
-resting BP
-resting HR
-resting ECG interpretation (normal/abnormal)
clean up procedures
-make sure mask, mouth piece, + hoses are placed in a plastic container
-discard all gauze/alcohol wipes + towels
-remove gloves + discard them
-wash your hands thoroughly with soap + warm water
