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ACE Group Fitness Instructor Manual
Chapter
 Exercise
1
Physiology
ADAPTATIONS TO EXERCISE
1
Cardiorespiratory adaptations during acute aerobic exercise


Increased heart rate (HR)
Increased stroke volume
(SV)


SV is the amount of blood
pumped from each ventricle
each time the heart beats.
SV is measured in milliliters
(mL) per beat.
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Cardiorespiratory adaptations during acute aerobic exercise

Increased cardiac output


Cardiac output = HR x SV
A typical cardiac output at
rest:


60 bpm x 70 mL/beat = 4,200
mL/min (approximately 1 gallon
of blood per min)
During maximum exercise,
cardiac output can increase up to
4 to 7 times above resting level.
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Cardiorespiratory adaptations during acute aerobic exercise

Increased breathing rate

Increased systolic blood
pressure


This increase is due to the
cardiovascular system attempting
to increase oxygen delivery to the
working muscles.
However, blood pressure greater
than 250/115 mmHg is an
indication to terminate exercise
(hypertensive response).
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Cardiorespiratory adaptations during acute aerobic exercise

No change, or a slight
decrease, in diastolic blood
pressure


This is due to the dilation of vessels in
the muscles and the skin.
Vasodilation decreases peripheral
resistance.

This is an important benefit for individuals
suffering from heart disease, hypertension,
diabetes, and peripheral vascular disease.
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Cardiorespiratory adaptations during acute aerobic exercise

Blood is shunted from the
viscera to the working
muscles


Partly caused by the dilation of
vessels that supply blood to the
exercising muscles
Partly caused by the constriction
of vessels that supply blood to the
abdominal area
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Cardiorespiratory adaptations during acute aerobic exercise

Increased extraction of
oxygen from the blood into
the working tissues


An average healthy person is able
to load the blood with more
oxygen in the lungs than he or she
is able to use at the cellular level.
Therefore, the more efficiently an
individual can extract oxygen from
the hemoglobin in the capillaries,
the more physical performance
improves.
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Oxygen extraction
•Oxygen enters lungs.
•Oxygen loads onto
hemoglobin in blood
and is transported to the
working muscle.
•Oxygen is unloaded
into muscle cell.
•Oxygen loads is
transported to
mitochondria.
•Mitochondria grow and
multiply with regular
exercise to increase
metabolic capacity.
Acute
Responses to
Aerobic Exercise
Oxygen
consumption during
exercise
•Oxygen deficit.
•Steady State
•EPOC (excell post
exercise oygen
consumption.
Copyright © 2007 Lippincott Williams & Wilkins
Figure 4.7
Acute Responses to Aerobic Exercise
Lactate Threshold

Also known as anaerobic threshold (AT).

The point at which blood lactic acid
suddenly rises during incremental exercise

Characterized by feeling “out of breath”
and feeling a burning sensation in the
working muscles.

Can be used as a marker of exercise
intensity
Acute Responses to Aerobic Exercise
Lactate threshold Values
 Average

individuals
LT 40-60% of VO2 max
 Endurance

trained
LT>70% VO2 max.
Guidelines of Improving CardioRespiratory endurance

Four basic training variables

F = frequency

I = intensity

T = time

T = type (mode)
Chapter 11 - Injury Prevention &
Emergency Procedures
12
Guidelines of Improving
Cardio-Respiratory endurance
General Principles of Training



Specificity— the body will adapt to
the specific stress introduced.
Overload--Manipulating any one of
the four variables will result in
overload.
Reversibility—use it or lose it.
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14
Importance of warm-up

Increases blood flow to active
muscles

Increases blood flow to myocardium

Increases the dissociation of
oxyhemoglobin

Earlier sweating

May reduce abnormal heart rhythms
Copyright © 2007 Lippincott Williams & Wilkins
Importance of cool-down

Prevents venous pooling

Helps remove lactic acid

Allows CV system to return to a
resting state gradually.
Cardiorespiratory adaptations from regular aerobic training

Decreased RHR


With consistent exercise (as
few as three months of
regular aerobic training), the
interior dimensions of the
ventricles increase, allowing
them to hold more blood.
The same cardiac output can
be maintained at a lower HR
due to the greater SV.
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Cardiorespiratory adaptations from regular aerobic training

Decreased relative
working heart rate


Since a given intensity
requires a given amount of
oxygen, HR at any given
intensity will be lower due to
an increased SV.
A trained individual will have
to work at higher intensities to
achieve the same HR he or
she achieved prior to physical
training.
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Cardiorespiratory adaptations from regular aerobic training

Increased VO2max as SV
increases


VO2max (aerobic capacity) is the
total capacity to take in, transport,
and use oxygen during strenuous
exercise.
VO2max depends on two factors:


The delivery of oxygen to the
working muscle by the blood
(cardiac output)
The ability to extract oxygen at the
capillaries and use it in the
mitochondria
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Cardiorespiratory adaptations from regular aerobic training

Increased oxygen extraction




This results in an improved ability
to remain “aerobic” at higher
intensities.
Partly due to increased capillary
density
Partly due to increased
mitochondrial density
Partly due to an increased ability
to create adenosine triphosphate
(ATP)
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Cardiorespiratory adaptations from regular aerobic training



Increased fatty acid oxidation
at any submaximal intensity
More glycogen is stored in
trained muscles and less lactic
acid is produced
Increased tolerance to lactic
acid produced during exercise
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