The Effect of Aerobic Exercise on the Cardiorespiratory System
Consistent aerobic exercise has many physiological effects on the
cardiorespiratory system. The heart like any other muscle needs
exercise, this exercise comes in the form of aerobic exercise. In
this assignment I am going to illustrate the changes that occur in
certain areas of the cardiorespiratory system when aerobic exercise is
undertaken:
Ø Stroke volume
Ø Heart rate (pulse and rhythm strip)
Ø Cardiac output
Ø Blood flow
Ø Myocardium
Ø Fatty deposits
Ø Capillarisation
Stroke volume
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As a result of aerobic exercise the S.V. shows an overall increase.
S.V. at rest is substantially higher after an endurance training
programme than it is before training.
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The graph above shows the changes in stroke volume of a subject before
and after a six-month endurance-training programme.
After training the left ventricle fills more completely during
diastole than it does in an untrained heart, this happens because of
an increase in the blood plasma volume, which in turn means more blood
is available to enter the ventricle causing an increased end diastolic
volume (EDV).
More blood entering the ventricle increases the stretching of the
ventricular walls. This results in a stronger elastic recoil. The
thickness of the posterior and septal walls of the left ventricle
increase slightly with endurance training.
Increased muscle mass in the ventricle can lead to a more forceful
contraction. Increased contractibility coupled with the increased
elastic recoil increases the ejection from the trained heart. More
blood enters the left ventricle and a greater percentage of what
enters is pushed out in a single contraction.
Heart rate
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The heart rate is one of the easiest ways to measure cardiovascular
activity. H.R. reflects the amount of work the heart has to do to meet
demands of the body. To measure H.R. the pulse is taken at the radial
artery on the wrist.
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