Download oxygen uptake, oxygen deficit and oxygen debt

OXYGEN UPTAKE, OXYGEN DEFICIT AND OXYGEN DEBT.
WORDS YOU NEED TO KNOW:
Oxygen deficit
Oxygen debt
EPOC
Steady state
Anaerobic threshold
Aerobic capacity
Anaerobic power
VO2 max
Cardiac output
Acute responses
Cardiovascular system
Respiratory system
Plateau
The period after the onset of exercise
where oxygen consumption is below
that required to produce all the ATP
needed aerobically.
Amount of oxygen that has to be
repaid to the working muscles after an
anaerobic effort has finished. There
are two phases alactacid and
lactacid.
Recovery oxygen consumption (excess
post-exercise oxygen consumption) or
O2 debt
The point during exercise when oxygen
supply equals oxygen demand.
The point at which lactic acid begins
to accumulate (often expressed as
occurring at 85% of MHR or 70% of VO2
max).
The maximum amount of oxygen the
body can take in, transport and use.
Refers to the ability to produce energy
(ATP) without using oxygen.
The maximum amount of O2 that can
be taken up, transported and utilized
per minute.
(Q) amount of blood ejected from the
left ventricle of the heart per minute.
h.r x s.v = Q
A short term physiological response to
a condition or exercise that is followed
by a return to pre-exercise levels once
the condition is removed or stopped.
The system of organs (pertaining to the
heart, blood vessels and blood) that is
responsible for the transportation of
blood around the body.
The system of organs (nasal cavity,
pharynx, larynx, trachea, bronchi and
lungs) that makes oxygen available
and carries carbon dioxide away.
Commonly occurring when the body
adjusts to new loads and maintenance
Epinephrine
Pulmonary ventilation
Gas exchange / diffusion of O2 (lungs)
myoglobin
Mitochondria
of existing conditions/ state prevails.
A hormone secreted by the adrenal
medulla (brain): important in regulation
of arterial blood pressure. The
elevated levels of the hormone
epinephrine secreted during exercise
increase the oxygen consumption of
the body.
Lung (pulmonary) ventilation
(breathing).
Gases diffuse from high to low pressure
– O2 high in lungs low in blood and vise
versa CO2 high in blood and low in
lungs.
Oxygen binding protein found in the
muscle that attracts O2 from the
bloodstream into the muscle.
Powerhouse of a cell. Place where ATP
resynthesis occurs and where glycogen
and triglycerides are oxidized. The
more mitochondria and the greater
their size the greater the oxidization of
fuels to produce ATP aerobically!
OXYGEN INTAKE
Pulmonary ventilation
OXYGEN TRANSPORT
Diffusion of O2 from lungs
to blood
Cardiac output
Blood flow to the muscle
OXYGEN UPTAKE
Uptake of O2 by skeletal
muscle (myoglobin)
OXYGEN CONSUMPTION
O2 used in the muscle
fibre (mitochondria)
Important things to note:
 There is a linear relationship between heart rate and oxygen
consumption (therefore the greater the intensity the greater the O2
consumption) – to a point – when would this relationship stop?
 It is possible to work at 110% VO2 max because this indicates that
the athlete is working anaerobically – remember VO2 max is the
maximum amount of O2 that can be taken in, transported and
utilized per minute! Think about VO2 MAX test (previous student)–
towards the end he was supplying ATP anaerobically and had
gone above his VO2 MAX. The tester stopped him because she
could see that he was no longer supplying ATP aerobically.
 The 3 systems that need to work together for aerobic ATP
production are the respiratory, cardiovascular and muscular
systems.
 Most ACUTE responses that occur when exercising occur simply to
deliver extra oxygen to support ATP production. They occur at the
muscular, respiratory and cardiovascular levels just like chronic
adaptations. They include a reduction in CP stores, accumulation
of lactic acid, and increase in epinephrine, a reduction in
glycogen stores, an increase in muscle temp and an increase in
cardiac output.
 Blood is redistributed to the active muscle and to the skin and heart
and redirected from the liver, kidneys and digestive tract. All of the
acute responses depend on the intensity, duration and type of
activity, which muscles specifically are used, how much muscle
mass is involved, the type of muscle contraction and the level of
fitness of the athlete.
Resynthesise
ATP and PC
Lots of
biochemical
processes
require O2 in
recovery – some
are quick others
take longer
Resythesise
lactate back to
glycogen
EPOC
Restore
oxygen to
myoglobin and
blood
Oxidise lactate
Physical activity
ATP must be constantly supplied for muscle
contractions to continue during physical activity
ATP is supplied by the:
Aerobic system
Lactic Acid system
CP system
As a consequence of using the energy systems
acute responses occur
↓ CP stores
↑ cardiac output
↑ respiration rate
↑ heart rate
Redistribution of Q
↑ lactic acid levels
↓ glycogen stores
↑ muscle temperature
↑ secretion of epinephrine
↑ supplies of ATP
An oxygen debt is incurred
O2 recovery consumption (EPOC) levels remain elevated until
body returns to pre exercise levels
The additional O2 is used to:
Convert lactic acid to pyruvic acid
Convert pyruvic acid to glucose in the liver
Restore CP stores
Help energy systems recover
Resting levels again

Steady state – level of O2 consumption = demand! After this point if high
intensity work continues to increase the demand for O2, the acute
circulatory and respiratory responses cannot act quickly enough to satisfy
the demand for O2 therefore the athlete begins to produce ATP
anaerobically.
QUICK QUIZ
1. Which of the following gives a correct path of blood when flowing around
the body?
a. LV, LA, RV, RA and tissues
b. LV, tissues, lungs, RA, RV, LA
c. LV, lungs, RA, RV, tissues, LA.
d. LV, tissues, RA, RV, lungs, LA.
2.
a.
b.
c.
d.
Blood leaves the left ventricle through a blood vessel called the:
pulmonary artery
pulmonary vein
aorta
vena cava
3. The quantity of oxygen carried by the blood depends on its combining
with which of the following:
a. hydrochloric acid
b. carbonic acid
c. myoglobin
d. haemoglobin
4. In a normal blood pressure reading the larger figure refers to:
a. the pressure on the walls of the arteries at the moment of ventricular
contraction
b. the pressure on the cardiac muscle
c. the pressure on the walls of the veins during contraction of the heart
d. the pressure on the walls of the arteries at the moment of relaxation of the
heart muscle.
5. The basic difference between veins and arteries in the systemic circuit is
that:
a. veins carry a higher proportion of O2
b. many veins contain valves that prevents backflow of blood
c. blood pressure is lower in the arteries
d. the wall of the vein is thicker and stronger than that of the corresponding
artery.
6. In which of the following vessels does blood have the highest
concentration of oxygen?
a. pulmonary vein
b. pulmonary artery
c. venules
d. superior vena cava
7.
a.
b.
c.
d.
In the lungs exchange of gases occurs in the:
bronchii
bronchioles
alveoli
trachea
8.
a.
b.
c.
d.
An individuals aerobic capacity is reflected by his / her:
maximal oxygen uptake
skeletal muscle density
systolic blood pressure
respiratory rate
9.
a.
b.
c.
VO2 max refers to:
the maximum amount of oxygen you can breathe out in one breath.
The size of your lungs
The maximum amount of oxygen you can consume and utilize in your
body per minute
d. The relationship between tidal volume and the rate of breathing.
10. The degree to which the transfer of oxygen from blood to muscle tissue
occurs is reflected in:
a. cardiac output
b. diastolic blood pressure
c. haemoglobin uptake
d. arterio-venous oxygen difference
11. When your heart rate levels out during sub-maximal exercise, this
indicates:
a. oxygen availability is sufficient to meet the energy demands
b. a high level of fitness
c. the lactic acid is restricting muscle contraction
d. that muscle glycogen stores have been depleted.
12. Two individuals, one trained athlete (resting heart rate 50 bpm) and the
other a relatively sedentary person (resting heart rate 75 bpm), both work
sub-maximally on a bike ergometer at the same workload for 15 minutes.
Both are the same weight. Once a steady state has been attained:
a. the trained athlete would have a higher heart rate
b. the untrained person would have a higher heart rate
c. their heart rates would be the same
d. their heart rates would be dependent upon their respiratory rates.
13. During recovery from exercise our oxygen consumption continues above
resting levels for a considerable time. The initial phase of the oxygen debt
lasting for 2-3 minutes is the:
a. alactacid debt component, concerned with removal of lactic acid
b. lactacid debt component, concerned with the removal of lactic acid
c. lactacid debt component, concerned with the restoration of PC and ATP
d. alactacid debt component concerned with the restoration of PC and
ATP.
14. The period where the oxygen uptake is less than that required for the
amount of work being performed is called:
a. oxygen deficit
b. oxygen debt
c. steady state
d. glycogen fatigue
15. Which of the following is the best example of oxygen deficit?
a. the marathon runner sparing himself over the first 10kms.
b. The 400m runner feeling his legs growing heavy in the home straight
c. The 100m runner breathing heavily for minutes after the race
d. The sprinter running his race without needing to breathe.
16. Increased amounts of myoglobin in muscles occurs due to training. This
would be beneficial in aerobic activity because myoglobin:
a. provides energy to form ATP
b. facilitates the diffusion of oxygen from the blood to the mitochondria
c. is the muscular part of the heart, and a stronger heart enables faster
blood circulation
d. will enable a quicker diffusion of oxygen from the lungs to the blood.
QUIZ ANSWERS
1D, 2C, 3D, 4A, 5B, 6A, 7C, 8A, 9C, 10D, 11A, 12B, 13D, 14A, 15B, 16B.
Cover Peak Performance Questions 2,4,6,7,9,10,12,14 and EQ 1 & 2
Notes
Q2
a.
3 immediate changes – therefore meaning acute changes and watch
that it only asks for changes from the cardiovascular system, not muscular and
respiratory!!
Increased Heart rate
Increased SV
Increased Q
b.
Respiratory only!
Increased ventilation
Increased pulmonary diffusion
Increased inspiration and expiration volumes
Increase in tidal volume
Q4
a. and b.
Lungs
Facilitate the exchange of O2 and CO2 from the air to the blood
Increased gas exchange due to increased respiration rate; increased activation
of alveoli
Heart
Pumps O2 filled blood and CO2 rich blood around to the body and the lungs
increased heart rate
Capillaries:
Responsible for gas exchange at the muscles and organs
Increased gas exchange at the muscles = increased aVO2 diff, increased
activation of capillaries
Blood
Haemoglobin component of blood carries O2 around the body to the working
muscles
Increased speed of flow, increased systolic blood pressure, more blood flow to
the working muscles, decreased flow to non essential organs e.g. stomach,
possibly increased blood flow to skin for cooling
c.
1. The acute respiratory responses – increased ventilation, gas diffusion
or oxygen uptake
2. The acute circulatory responses – increased Q, SV, h.r, venous
return, blood flow to the working muscles, blood pressure, aVO2
diff.
3. The acute muscular responses – increased contractions,
temperature, O2 extraction, enzyme activity, blood flow to the
working muscles and decreased ATP /PC stores, muscle glycogen
and triglycerides.
6
a. As he goes through each stage his O2 consumption rises. From
start to the last 2 kms it rises 5.27 l/min.
b. Because of the intensity, duration and muscle mass involved in the
20km walk. Additional demands could be: increases in intensity,
oxygen uptake, transport, extraction and consumption all rise.
c. Supply meets demand. The athlete is typically working aerobically,
with aerobic glycolysis fuelling the muscles. It can take several
minutes to reach SS because of HR, RR and circulation, which all
need time to move from resting levels to that required to meet the
demand.
Q7
a.
↑ heart rate
↑ SV
↑Q
↑ gas diffusion
↑ ventilation rate
↑ a-VO2 diff
Vasodilation
Reduce blood flow to inactive organs
Increased blood flow to working muscles
Q9
a.
Q10
a.
b.
c.
d.
Q12
a.
b.
Skeletal muscle – to provide O2 for aerobic glycolysis, skin for cooling,
heart to meet the additional demands for pumping blood around the
body
The relationship shows that as the treadmill grade increases so too
does O2 consumption. It is a linear relationship
could say – increased heart rate, SV, Q or tidal volume
Yes
Level of O2 consumption does not level out until 7% treadmill grade.
SS is not evident until this point. The high intensity work increases the
demand for O2. The acute circulatory and respiratory responses
cannot act quickly enough to satisfy the demand for O2. Demand
exceeds supply.
B
Larger O2 debt, larger oxygen deficit, higher levels of oxygen
consumption, doesn’t reach SS rate of oxygen uptake.
c.
i has lower level of O2 consumption than B
ii
has a smaller oxygen deficit than B
iii
has a smaller oxygen debt than B
iv
has a shorter recovery period than B
Q14
A
i
Ii
b.
c.
a change in intensity
a change in conditions / terrain e.g a steeper gradient
O2 consumption remains elevated at the end of exercise and 2
minutes into recovery is higher than oxygen consumption at rest
Additional O2 is also needed for recovery of energy systems,
restoration of PC, conversion of la to pa and conversion of pa to
glucose in the liver. It represents O2 debt – EPOC.
Exam Questions
1.
a This is possible due to the involvement of anaerobic
system/s.
1.
b.O2 deficit is when the O2 consumption is below that necessary
top provide all the energy (ATP) aerobically.
1.
cThis is to allow the aerobic system to replenish the anaerobic
systems. Replenish ATP – PC store and remove LA (alactacid and
lactacid components of O2 debt.
2a
2b
There is a finite capacity for oxygen deficit which is reached (or
almost reached) in these 3 events.
The rate of energy release is lower during longer events and
therefore the speed is reduced. For the 1500m race, the speed is
slower because the rate of energy release is less compared to that
of the 400m and 800m races.