Download Increased ventilation – more oxygen taken in per minute means that

Acute Responses to Exercise
Chapter 4 – Glossary Words
 Ventilation (V)
How much air is breathed in and out in one minute
Increased ventilation – more oxygen taken in per minute means that more
oxygen is available to be transported to the working muscles resulting in an
improvement in aerobic performance.
 Tidal Volume (TV)
How much air is inspired or expired in one breath
Increased tidal volume – more oxygen taken in with each breath which
contributes to an increase in ventilation meaning that more oxygen is available
to be transported to the working muscles resulting in an improvement in aerobic
performance.
 Respiratory Rate (RR)
The number of breaths taken in one minute
Increased respiratory rate – more breaths per minute which contributes to an
increase in ventilation meaning that more oxygen is available to be transported
to the working muscles resulting in an improvement in aerobic performance.
 Plateau
To reach a period or level where no change is observed
At steady state oxygen supply is able to meet oxygen demand. When this occurs
the respiratory rate and tidal volumes both remain constant.
There is always a “lag” or delay from the time we start to exercise, and the
ability of our body’s respiratory and cardiovascular systems to keep up with
demands. For example, when we start to run, demand is high but all of our
respiratory and cardiovascular mechanisms cannot go from resting levels to 70%
max in a matter of seconds. This delay is known as the oxygen deficit (deficiency
of oxygen) and ATP is produced anaerobically by the PC and LA systems working
together to take up the body system “lag”.
 Ventilatory Threshold
The point where ventilation increases at non-linear rate
 Diffusion
The movement of molecules from an area of higher concentration to one
of lower concentration
Increased diffusion – more oxygen diffuses across the alveolar-capillary
membrane meaning that more oxygen is available to be transported to the
working muscles resulting in an improvement in aerobic performance.
 Cardiac Output (Q)
The amount of blood pumped out of the heart in one minute
 Stroke Volume (SV)
The amount of blood ejected by the left ventricle per beat
Stroke volume plateaus during submaximal activity at approximately 40-60% of
maximal exercise capacity. Stroke volume plateaus at this exercise intensity
because there is insufficient time for further filling of the ventricle as a result of
simultaneous increases in heart rate.
 Heart Rate (HR)
The number of times the heart beats in one minute
Heart rate increases during physical activity in order to increase oxygen delivery
to the working muscles whilst at the same time, facilitating the removal of waste
products such as carbon dioxide.
 Systolic Blood Pressure
Pressure in the arteries following contraction of ventricles as blood is
pumped out of the heart
 Diastolic Blood Pressure
Pressure in the arteries when the heart relaxes and ventricles fill with
blood
 Body Temperature
When exercise commences, there is an increase in the rate of
metabolism required to produce ATP in the muscle. Heat is the byproduct of the movement between the chemical fuels and body
movement as the body’s temperature increases. The body produces
sweat glands as a result.
Increased muscle temperature – increased rate of metabolism therefore heat
generated as a by-product due to increased production of ATP to meet the high
energy demands of the event assisting in anaerobic performance.
 Blood Redistribution
During exercise, blood flow is redirected away from the spleen, kidneys,
gastrointestinal tract and inactive muscles to the working muscles, so
that these muscles receive the greatest percentage of the cardiac output
Increased blood flow to the muscles – redistribution of blood flow from internal
organs to working skeletal muscles (80-90%) to address the increase in demand
for extra fuels and oxygen to produce energy assisting in anaerobic
performance.
 Venous Return
Is the rate of blood flow back to the heart
 Vasoconstriction
A decrease in the diameter of a blood vessel, resulting in a decrease in
blood flow to the area supplied by the blood vessel
 Vasodilation
An increase in the diameter of the blood vessel, resulting in an increase in
blood flow to the area supplied by the blood vessel
Vasodilation increases blood vessel diameter and thus blood flow to certain body
areas and vasoconstriction reduces the blood vessel diameter and thus
associated blood flow to certain body areas. It should be noted that one cannot
occur without the other and this mechanism is controlled by the brain sending
signal to small muscular rings/sphincters surrounding blood vessels that lead to
dilation or constriction.
 A-vO2 difference
Difference in oxygen concentration in the arterioles compared with the
venuoles
The arterio-venous oxygen difference (a-vO2 diff) will increase during
exercise as working muscles extract more oxygen from the blood into the
muscle to produce aerobic energy during exercise – up to 75% more than
at rest.
 Motor Unit
A motor neuron and the muscle fibres it stimulates
Increased motor unit and muscle fibre recruitment – more motor units recruited
and muscle fibres activated to produce explosive movements assisting in
anaerobic performance
 Energy Substrates
The chemicals that are required to resynthesise ATP i.e. PC, glycogen,
triglycerides
Increased muscle enzyme activity – increased muscle enzyme activity to produce
the increased amounts of ATP required by the muscles to meet the high energy
demand assisting in anaerobic performance.
The 110m Hurdles event is predominantly anaerobic therefore the athlete would
mainly see a decrease in ATP and PC stores. A marathon (42.2kms) event is
predominantly aerobic therefore the athlete would see a decrease in ATP and PC
stores as well as a greater decrease in glycogen and triglyceride stores.
 Adenosine Triphosphate (ATP)
A chemical compound made up of adenosine and three phosphate
molecules. ATP is the immediate source of energy for all muscular
contractions
 Adenosine Diphosphate (ADP)
A chemical compound made up of adenosine and two phosphate
molecules
 Phosphocreatine (PC)
A chemical fuel (also called creatine phosphate or CP) consisting of a
bound phosphate and creatine molecule
 Lactate
Lactate is produced when your body burns glucose. Once produced,
lactate is reprocessed as glucose and used as a fuel
 Blood Lactate
Blood lactate levels will be lower during sub-maximal physical activity as
compared to maximal exercise where the level of blood lactate will be higher.
This is because during sub-maximal activity the athlete is relying primarily on the
aerobic system at this intensity. This results in little production of lactate and
lactate levels in the blood remain low. When exercise intensity increases to
maximal levels the athlete is relying on the anaerobic systems and this results in
the production of increased amounts of lactate. This then enters the blood and
blood lactate levels begin to rise as the rate of lactate production begins to
exceed the rate at which lactate can be removed from the blood and will begin
to accumulate in the body.
 Lactate Inflection Point (LIP)
The exercise intensity beyond which lactate production exceeds removal,
sometimes referred to as the lactate threshold
The lactate inflection point represents the final balance point between maximal
lactate production and maximal lactate removal and still sees the aerobic energy
system producing most of the ATP. Higher work-rates will see the amount of
lactate produced exceed the rate at which it can be removed and hence lactate
and H+ will accumulate.
The lactate inflection point (LIP) is triggered during exercise when the rate of H+
accumulates faster than what it can be removed. Typically this occurs when the
muscles’ oxygen demand is quite high and the body systems struggle to supply
increased amounts of oxygen to working muscles. Increases in EPOC or the
oxygen debt occur during recovery whilst oxygen consumption remains above
resting levels. This typically occurs when an active recovery is being performed in
an effort to oxidise H+ ions at a faster rate due to increased oxygen availability
than if a passive recovery is undertaken.
 vO2 Max
The maximum amount of oxygen that can be taken up, transported and
utilised per minute