Acute effects;
The first thing that happens to a athlete's body before starting the activity is they start thinking about exercising which stimulates a response by the body and releases adrenaline; increases heart rate so the body is ready and prepared to exercise. This also tells your hormones that your body is going to exercise. This is known as the Heart Rate Anticipating Response. Then this moves onto to the next response. The systolic blood pressure increases to force blood around the body during exercise. The Diastolic blood pressure increases, there is a greater relaxtion phase to allow more blood to fill chambers ready to be sent around the body.
Vasoconstriction is when the size of your blood vessels become smaller which increases blood pressure; stops blood from passing through. During exercise the muscles that are working require an increase in blood to keep them working as a result the areas of the body that are not working (hormonal and reproductive) have the blood restricted to them. The arteries around these areas are made smaller so the blood flow is lessend. This is known as Vasoconstriction. Vasodilation is when the size of the blood vessels become bigger and it decreases blood pressure; allowing blood to pass through because the blood vessels are wider. Vasodilation is the opposite of vasoconstriction, the working muscles that require extra blood results in the blood vessels in those areas opening up (dilation) so that more blood goes to those areas.
Chronic effects:
The long term responses that happen during exercise in the cardiovascular system are cardiac hypertrophy, increase in stroke volume, increase in blood volume, increase in cardiac output, decrease in resting heart rate, reduction in resting heart rate, decreased recovary time, increased aerboic fitness and capillarisation.
Cardiac hypertrophy:
Average size: approx. Size of a clenched fist.
Average size at rest: hypertrophy occurs in the heart as it would in any other muscle.
Increased chamber size: atria and ventricles increase in size.
Increase in blood flow: increased chamber size allows more soace for blood flow through the heart.
This leads to increase in stroke volume, this is the volume of blood pumped out of the heart rate, which is 70ml.
It continues and leads to increase in blood volume because the stroke volume is how much blood is pumped out of the heart rate which will increase the blood volume.
With an increase in the size of the heart more blood can be pumped out of the heart each time it beats. At rest 15 - 20% circulating blood supplies skeletal muscle.
During vigorous exercise this increases to 80 - 85% of cardiac out. Cardiac out put is the amount of blood pumped out per minute measured in litre/minute. It is product of stroke volume and heart rate (SV x HR). Increase in amount of blood per beat will result in the amount of blood pumped per minute.
Resting heart rate decreases due to a larger more efficient heart. With more blood being pumped out of the heart in each beat (increase in stroke volume) the heart rate can beat less times in a minute to get the same amount of blood around the body.
As the stroke volume increases (blood per beat) then the blood pressure decreases because the same amount of blood is pumped around in less beats and less force is required. The increase in the heart's ability to pump blood around the body means that the heart can pump out waste productd more efficiently (e.g. carbon dioxide and lactic acid).
Cardiac hypertropgy increased ventricular chambers, this means that more blood can fill these chambers. As more blood can fill the chambers, more blood can be pumped around the body meaning more oxygen is getting to the working muscles. This allows the muscles to work for longer as oxygen can be used to breakdown and help produce energy.
After, new capillaries may develop and the existing capillaries become more efficient. They bring about more efficient delivery of blood to the working muscles and more oxygen reaches the muscles.
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