Lab Exam 1- Lab 4 Flashcards
4 primary factors that affect an individuals maximal O2 consumption
Genetics
Sex
Age
Training status
at what point is VO2 max traditionally designated
when there is a plateau in O2 consumption with an increase in work rate
describe the test done in today’s lab
treadmill:
warmup to find speed at which we hit 70% of HRmax (this speed will remain constant)
2 min exercise bouts
after each stage, incline raised 2% (unless about 6.5 mph then 2.5%)
continue until 10% grade reached
cooldown at HR <100
cycle:
rpm stays constant at 80 rpm but resiatnce increased every minute
power output increased by 20 watts/stage and kp setting adjusted 0.25 kp
warmup for <130 bpm and must maintain 60 rpm
1 minute exercise bouts
record RPE at last 30 sec time point of each stage
cooldown
does endurance training slow the decline in maximal HR with aging
NO
does maximal HR increase with endurance training
NO
exercise economy
the O2 cost of exercise at a given speed (running) or power output (cycling)
factors that influence mvmnt economy
body mass
terrain
footwear
strides
fick equation
VO2= cardiac output (Q) (x) oxygen extraction
how are O2 consumption and work rate related
because EE is a function of work rate, O2 consumption increases linearly with work rate untul VO2 max is reached
how do we measure VO2 max
via indirect calorimetry during a maximal graded exercise test
how do you calculate HR max
HRmax= 208-(0.7*age)
how do you measure blood lactate
most accurately it is done via blood sample but can also be measured through ventilatory measures (VT)
in endurance running events, what is correlated to their speed at lactate threshold
10,000 m running pace
lactate threshold
point at which blood levels of lactate begin to rise exponentially
rate of perceived exertion (RPE)
a valid indicator of exercise intensity
developed to predict the HR of a 20 year old at a given work rate by multiplying the RPE by 10
ventilatory threshold
point at which there is a sudden increase in ventilation
estimate of lactate threshold (only a marker of LT- not causally related)
VO2 max is the product of what 2 things
cardiac output
AV O2 difference
VO2 max test is a measure of
maximal capacity to transport and utilize O2 during dynamic exercise involving a large muscle mass
VO2max is dependent on what 2 physiological factors
1) maximal ability of cardiovascular system to deliver oxygenated blood to working tissues
2) maximal ability of the working muscles to extract O2 and produce ATP aerobically
what are other ways (other than a plateau in O2 consumption and increase in work rate) make a VO2 max test valid
At least 2 of the following criteria must be met:
- plateau of O2 consumption at an increased work rate
- RER > 1.15
-HR > (age-predicted maximal HR - 10 BPM) using the equation HRmax= 208-0.7*age
-Rate of perceived exertion (RPE) >17
-Blood lactate >8mM
what does VO2 max represent
the physiological limit of the body to deliver and extract O2
what happens to maximal HR as we age
declines linearly with advancing age
what happens to muscle mass as we age
decreases
what is the most valid and reproducible assessment of cardiovascular fitness
VO2 max test
what is the reason we can see increased cardiac output following endurance training
due to an increase in maximal stroke volume
what mediates an increase in stroke volume
increases in end-diastolic volume (preload) and cardiac contractility and a decrease in afterload on the ventricles
what must a VO2 max test utilize
large muscle groups
ideally involves specific movements used by the athlete in their event (cyclists use cycle ergometers)
what produces a greater VO2 max value : cycle or treadmill and why
treadmill produces a higher VO2 max value due to involvement of more muscle masses
when comparing individuals at the same submaximal speed, would greater or less movement economy consume the least O2
greater movement economy
(costs less O2 to run at that speed)
when does LT and VT happen in untrained individuals
50-60% VO2 max
when does LT and VT occur in trained individuals
65-85% VO2 max
why can we have an increased arteriovenous O2 difference
due to increases in capillary density and mitochondrial density as well as other biochemical and metabolic adaptations
will an individual with a lower running economy consume more or less O2
more O2 at the same speed
how to calculate cardiac output (Q)
Q= HR x SV
VO2 max equation
MAXIMAL cardia output x MAXIMAL. a-v O2 difference
increase in SV max =
increases VO2 max
increase in (a-v)O2diffmax=
increase in VO2 max
As we age what happens to VO2 max
decreases
why does increasing HR max NOT increase VO2max in healthy young subjects
increase HR
but Q would remain the same since the heart is beating too fast so it can’t fill with as much blood, so SV decreases
specificity requirements for VO2 max testing
must use large muscle groups
should be sport specific, but can still provide valuable information if not
what ergometer yields a higher VO2
treadmill is usually 5% higher than cycling because you have a more active muscle mass
when is the typical LT (or VT) for untrained individuals
50-60% VO2 max
when is typical LT (or VT) for trained individuals
65-85% VO2 max
when do LT and VT occur
at a greater relative and absolute work rate
economy
O2 cost of exercise at a given submaximal speed/power output
poor economy
increased VO2 at a given submaximal speed
