Maximal Oxygen Uptake /limitations Flashcards
What is Vo2?
VO2max:
– Maximum amount of O2 which can be
consumed by the working muscles per
unit time by a person at a maximal work
rate.
It is the measure of aerobic systems’ power about the cardiovascular system which is expressed in absolute (l/min) or relative (ml/kg/min)
*
what are the factures that influence v02?
Mode of exercise
* Heredity
* State of training
* Sex
* Age
* Body size and composition
what are the variables associated with performance?
stroke volume
muscle mass
v02
capillary density/oxidative enzymes
hr max
cardiac output
max av02 diffusion
running economy
does vo2 decrease with age?
yes it does it decreases by 10% per decade after 30
what are some relationships v02 during exercise?
1) as heart rate increases so does vo2
2) Ve increases with v02
3) Blood Lactate Increases with vo2 (above threshold)
4) Rer increases with vo2
5) vo2 max increased with rpe
define anerobic threshold?
The intensity of exercise/workload
above which measurement of oxygen
uptake cannot account for
all of the required energy.
highest steady-state oxygen
uptake
it is the intensity at which oxygen supply can’t meet the demands of the muscles so steady state is not achieved
why is the steady state levels in untrained vs trained indiviual?
In a trained individual the steady states are at higher HR and take longer to reach those levels because of a higher capacity to deliver oxygen and muscles can use alot.
In an untrained person doesn’t take long to reach a steady state because of a decreased ability to utilze oxygen and a lower capacity for o2 to be used by the muscles
v02 max is reached how?
when the steady state cannot reach a plateau.
what are the components associated with anerobic threshold?
ventilatory threshold
Obla
respiratory exchange ratio
how many many ventilatory thresholds are there?
2
1) aerobic threshold when lactate is slightly elevated above resting
2) when blood lactate begins to accumulate
describe Ventilatory threshold 2?
1)The “excess” ventilation results directly from CO2
increased output from buffering of the lactate that
begins to accumulate from increased anaerobic
glycolysis
or
2) when ventilation increases as intensity does as well which is when lactate starts to accumulate and c02 is being produced at a faster rate
with increasing exercise ?
vc02 increases with v02
when vc02 is greater than 02 hyperventilation occurs because oxygen is not meeting energy demand.
both increase with workload
what does a higher Threshold mean?
It indicates a higher endurance capacity/ ability to sustain long periods of exercise and it is a better predictor of v02
define steady state?
steady state is when there is an equilibrium between lactate removal and production
what is obla?
Onset of Blood Lactate Accumulation is defined
as the intensity of exercise at which blood
lactate reaches 4 mM during an incremental
exercise test.
what are 4 limitations to v02?
oxygen-carrying capacity
Blood doping
EPO to increase [Hb]
Altitude training
muscle mass the largest consumer of O2 Loss of muscle = reduced VO2 Increasing mitochondrial enzymes = small increases in VO2max Important for endurance performance, not VO2max per se
cardiac output VO2max increases due to Q, not a-vO2 diff Athlete heart: increased SV
pulmonary diffusion capacity
At sea level, people that live at altitude have higher affinity of oxygen
what are cardiac output values?
Q during exercise
trained max 30-35L/min
trained rest
untrained 20-25L/min
stroke volume in different populations?
Elite
rest 100-120 /min
160-220 ml
trained
rest 80-90ml
Exercises 130-150ml
untrained
rest 55-75ml
exercise 50-110ml
plateau in stroke volume happens at 30 to 40% of v02
what are cardiac adaptions to the heart?
1) increased muscle /thickness Left ventricle wall because of:
* Pressure Overload
* Weight training
* Hypertension
2)Increased LV cavity size
* Volume Overload
* Endurance Training
what is an echocardiogram?
It is an ultrasonic technique that uses
sound waves to “map” the dimensions of
the myocardium and the volume of the
chambers
what is the av02 difference?
it is muscles’ the ability of muscles to extract oxygen from the amount that is present in the blood, which increases with exercise.
what factors influence afo2 deference?
plasma volume (more oxygen)
red blood cell volume
vascular function which means
increased delivery of blood to muscles or increased profusion
increased capillary and mitochondrial density leads to more around muscle better o2 extraction a
what are stroke volume values at rest ?
normal
Normal values Rest -20mL/dL - 15mL/dL = 5 difference. Exercising 20 - 5 = 15 mL/Dl difference
how quickly can v02 max increate?
according 2 a study
* 40 mins/day x 6 days/week for 10 weeks
* 3 days/week: 6x5 mins @ MAP (2 mins Rest)
* 3 days/week: Timed 30 min run (week 1), 35 min run (week 2), or 40
min run (week 3-10) for max distance
as endurance increases blood volumes. What is blood volume?
=5 liters of blood which accounts for 7-8% of total body mass
and about 2 liters is red blood cells
blood volume is composed of
plasma = 55%
90% water
7%protins
3% other
45% formed elements
99% red blood cells
1% white blood cells
what are rbc vs plasma ratios for or hematocrit percentile males and females?
expressed as the %RBCs in the whole blood
* Males: 45 - 47 %
* Females: 42 - 45 %
what does hemoglobin got to do with blood?
hemoglobin is a crucial component of blood and plays a vital role in its function.
Hemoglobin is a iron carrier protein found in red blood cells, and its primary function is to bind with oxygen in the lungs and transport it to the rest of the body’s tissues and organs.
Oxygen binds to the iron-containing heme groups within the hemoglobin molecules.
1 heme= 4 oxygens
65-75 x that of 02 concentration
what are hemoglobin numbers for males and females?
Hemoglobin Concentration ([Hb])
* Males: 13-17 g∙dL-1
* Females: 12-15 g∙dL-1
how much can 02 can each hb carry?
1g=1.34ml/02
and can be calculated by
blood capacity = hb g/dl x 02 dl
how can hb be affected and what are the affects?
Low hb
tired
sluggish
reduced capacity to work
weak
females=loss due to menstrual cycle
can be caused by
blood loss
decreased folic acid and vitamin b12
high hb
what is hemoglobin saturation/ %SaO2?
- Ratio of amount of O2
combined with Hb to the
maximum amount.
since there is more hb in the blood than o2 not all of it can be used
what affects %SaO2?
altitude
at sea level 97-98%
above sea level, it decreases
for example, 4000m is round 85%
csep exercising cutoff is 80%
how do we calculate sa02?
%SaO2 =( O2 content of Hb /)x 100
( O2 capacity of Hb)
what is the hb disassociation s curve?
the hemoglobin dissociation curve is a graphical representation of the relationship between the partial pressure of oxygen (PO2) and the saturation of hemoglobin with oxygen.
This curve shows how readily hemoglobin binds to or releases oxygen in response to changes in oxygen levels in the surrounding environment.
in addition to transporting oxygen, hemoglobin also helps in carrying carbon dioxide, a waste product, from the body’s tissues back to the lungs, where it can be exhaled. This process is essential for maintaining a balance in the levels of oxygen and carbon dioxide in the body
** Carbon monoxide is so dangerous because it has a greater affinity to carbon)
which is greater P02in artery or p02 in veins?
P02 is greater in the artery because of a higher 02 concentration ~mmHg
P02 is less in the vein because of o2 loading and delivery about 40mmhb
how does exercise affect P02?
well during exercise their is a greater demand of 02 by the muscles compared to rest therefore it shifts to the right.
hemoglobin’s affinity for oxygen changes with varying oxygen levels.
what influences the oxy-hemoglobin s curve?
metabolic activity
increased blood flow
Bohr effect as I acidity increases due to c02 production which enhanced unloading of 02
