Download acute or immediate responses to exercise teach

Chapter 5:
O2 Uptake, Deficit and Debt
O2 Uptake, Deficit and Debt- immediate responses to exercise:
Upon the onset of exercise, the body must undergo significant changes to allow
oxygen to move to the working muscle. This is because O2 is required for ATP
resynthesis during aerobic metabolism.
What has changed?
 Diaphragm and
intercostal muscle activity
Why does this occur?
 demand for oxygen,  in respiratory function so these muscles need
to work harder
 Ventilation of the lungs
Because of the  demand for O2 the lungs will inhale and exhale MORE
than at resting levels
 Oxygen and Co2
diffusion
Respiratory function includes the diffusion of gases
 HR
To more the oxygen to the working muscle
 Stroke volume (SV)
The left ventricle will fill more during exercise (the heart is an elastic
muscle and as the demand for more blood  the hearts capacity to
deliver as well
Q=HR X SV
 Cardiac output (Q
L/min)
 a-VO2diff
The amount of O2 extracted from the working muscle  as exercise
levels 
 Oxygen consumption
There is an  is the body’s demand to produce ATP aerobically so the
amount of O2 consumed by the body 
 Myoglobin activity
Is a commonly found protein found in muscles. It acts as the intracellular
storage site for oxygen. As exercise levels  myoglibin plays a large roll.
 PC stores
Phosphate energy system uses PC to replenish ATP stores
 La and H+ production
If oxygen is present, pyruvate molecules enter the mitochondria and are oxidised to
carbon dioxide and water in a process called aerobic respiration. If oxygen is
absent, as is the case with intense exercise such as the 100m sprint, the pyruvate
become oxidised to lactic acid and hydrogen ions.
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.
Glycogen is utilised during high intensity exercise (85% of max HR or
above)
 Epinephrine secretion
 Glycogen stores
 Muscle temp
As use of skeletal muscles , their temperature 
 Redistribution of blood
flow to working muscles
 is demand for O2 leads to a greater blood flow to the working muscle
How does VO2max fit in??
An example of the VO2max is as followsVO2max (ml/kg/min = Q (L/min) X a-VO2diff (mL/100mL)
24000 mL X18mL/100mL = 432000 mL
Assume these figures belong to a 60kg trained marathon runner the VO2max will be:
430000mL ÷ 100mL and ÷ 60kg
= 72 ml/kg/min.
EPOC- Oxygen debt
Another term used for oxygen recovery is EPOC – excess post-exercise
oxygen consumption.
Alactacid Debt – Oxygen used to restore ATP and PC stores
Lactacid Debt - Oxygen used to remove lactic acid from cells/blood.
Additional oxygen is used to recover the energy systems.
EPOC Fast Replenishment
(0 _ 3 minutes)
Slow Replenishment
(0 minutes _ hours)
ATP resynthesis
PC resynthesis
Return core temperature to pre-exercise
levels
LA converted to CO2 & H2O
Restore oxygen to myoglobin
Absorption of H+ ions (buffering)
LA converted to glycogen, protein &
glucose
Restoring heart rate, ventilation & other
body systems to pre-exercise levels
It is important to note the relationship between exercise intensity and the factors of
O2 deficit, debt and steady state.
An activity that rapidly calls upon the anaerobic systems will have a large oxygen
deficit, possibly no or very small steady state and a large oxygen debt/EPOC
An activity that rapidly calls upon the anaerobic systems will have a large oxygen
deficit, possibly no or very small steady state and a large oxygen debt/EPOC
An activity performed at lower intensities will have a smaller oxygen deficit, a longer
steady state and a smaller oxygen debt/EPOC.
During activities where steady state has been established and the La system is called
upon increasingly to supply ATP (such as surges or short sprints), these contribute to
oxygen deficit and hence add to the oxygen debt during recovery. This extends the
“slow replenishment” part.
People who have undergone aerobic training will be able to “consume” a greater
volume of oxygen during steady state exercise and thus the anaerobic energy system
contribution becomes proportionately smaller at a earlier stage of the activity.
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
Epinephrine
Pulmonary ventilation
Gas exchange / diffusion of O2
(lungs)
myoglobin
Mitochondria
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 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.
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.
a.
b.
c.
d.
In a normal blood pressure reading the larger figure refers to:
the pressure on the walls of the arteries at the moment of ventricular contraction
the pressure on the cardiac muscle
the pressure on the walls of the veins during contraction of the heart
the pressure on the walls of the arteries at the moment of relaxation of the heart
muscle.
5.
a.
b.
c.
d.
The basic difference between veins and arteries in the systemic circuit is that:
veins carry a higher proportion of O2
many veins contain valves that prevents backflow of blood
blood pressure is lower in the arteries
the wall of the vein is thicker and stronger than that of the corresponding artery.
6.
a.
b.
c.
d.
In which of the following vessels does blood have the highest concentration of oxygen?
pulmonary vein
pulmonary artery
venules
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.
9.
a.
b.
c.
d.
An individuals aerobic capacity is reflected by his / her:
maximal oxygen uptake
skeletal muscle density
systolic blood pressure
respiratory rate
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
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