Lab class 2: predicting max O2 uptake Flashcards
Why is it important to know about O2 uptake
VO2 max gold standard measurement of CRF
decrease in VO2 max = increase in RR of all cause mortality and CVD mortality
having lowest quartile of VO2 max shown to be greater risk factor for CVD mortality than common risk factors e.g obesity
Give reasons why determining of VO2 max by maximal tests isn’t always feasable
elderly unable to do
requires expensive equipment and trained practitioners so not practical
outline the process of the Bruce Hill treadmill protocol
graded exercise test performed to exhaustion
duration last for predicts VO2 max
HR, BP, RPE and ECG taken throughout
Outline the process of the Astand Rhythmic cycle ergometer test
determining HR response to sub max exercise to estimate VO2 max
work load determined by sex and conditioning load
then cycle at 50RPM
Aim to get HR between 125-170
record HR at 5th and 6th min and then average
potentially need to adjust HR for age by multiplying by a correlation factor
Plot HR and work rate to predict VO2 max
What assumptions are made when using the astrand rhythmic cycle ergometer test
steady state of HR reached at each stage
linear relationship between HR and WR
minimal difference between actual and predicted max HR
everyone has same mechanical efficiency
no medication, no caffine, no stress, not hot
Outline the process of the chester step test
record age and resting HR
calculate 80% max HR
explain test, stepping up and down in time to recording, speed increases
record HR and RPE at each stage
plot HR on graph
draw LOBF if HR was >50% max
when LOBF reaches 80% HR max, draw line to extrapolate VO2 max
Under what circumstances would you stop a chester step test
HR > 80% max
RPE > 14, moderatly hard
dizzy, overtired or faint
why is a chester step test good for testing VO2 max in the field
easy to do
no need for specialist equipment
submaximal
what is the subject asked about in non exercise VO2 max estimation and what other factors are used in the calculation
Percieved functional ability
physical activity rating
BMI
sex
what is the limitation of using indirect measurements of VO2 max
potential for overestimation
below which percentile of VO2 max is indicitive of a sedentary lifestyle
20th
how can knowledge of a patients VO2 max be used in primary and secondary rehabilitation programmes
educate them about health status relative to matched norms
planning of exercise programs
baseline and follow up comparison
