Adaptations of the Cardivascular System to long term

7/29/2019 Adaptations of the Cardivascular System to long term

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Adaptations of theCardivascular System to long

term exercise


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Five important functions duringexercise

Delivers oxygen to working muscles Oxygenates blood by returning it to the

lungs

Transports heat from the core to the skin Delivers nutrients and fuel to active

tissues

Transports hormones


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Effect of Exercise

Exercise places an increased demand on thecardiovascular system. Oxygen demand bythe muscles increases sharply. Metabolic

processes speed up and more waste iscreated. More nutrients are used and bodytemperature rises. To perform as

efficiently as possible the cardiovascularsystem must regulate these changes andmeet the bodys increasing demands


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Important Aspects

Heart Size

Heart rate

Stroke volume Cardiac output

Blood flow

Blood pressure Blood Volume


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Heart Size

The hearts mass and volume increase andcardiac muscle undergoes hypertrophy.

It is the left ventricle that adapts to thegreatest extent. As well as the chambersize increasing as a result of endurancetraining, more recent studies show thatthe myocardial wall thickness alsoincreases.


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Heart Rate

Resting heart rate can decrease . Highlyconditioned athletes such as Lance Armstrong canhave resting heart rates in the low 30s.

During submaximal exercise, heart rate is lower at

any given intensity compared to pre-training. Thisdifference is more marked at higher relativeexercise intensities.

Maximum heart rate tends to remain unchanged bytraining and seems to be genetically limited.

However, there are some reports that maximumheart rate is reduced in elite athletes compared tountrained individuals of the same age.

Following an exercise bout, heart rate remainselevated before slowly recovering to a resting level.

After a period of training, it is faster.


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Stroke Volume

Stroke volume increases at rest, during submaximalexercise and maximal exercise following training.

This increase can lead to greater filling of the leftventricle. This is due to an increase in blood plasma

and so blood volume and reduced heart rate whichincreases the diastolic filling time.

This increased filling on the left ventricle increasesits elastic recoil thus producing a more forceful

contraction. So not only is the heart filled withmore blood to eject, it expels a greater percentageof the end-diastolic volume.

In Elite athletes is can be 90-110ml/beat.


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Cardiac Output

Cardiac output remains relatively unchangedor decreases only slightly following endurancetraining.

During maximal exercise, cardiac outputincreases significantly. This is a result of anincrease in maximal stoke volume as maximalheart rate remains unchanged with training.

In elite athletes, maximal cardiac output canbe as high as 40L.min.


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Blood Flow

Skeletal muscle receives a greater bloodsupply following training. This is due to:

Increased number of capillaries

Greater opening of existing capillaries

More effective blood redistribution

Increased blood volume


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Blood Pressure

Blood pressure can decrease (both systolicand diastolic pressure) at rest and duringsubmaximal exercise

At a maximal exercise intensity systolicblood pressure is decreased compared topre-training.

Although resistance exercises can raisesystolic and diastolic blood pressuresignificantly during the activity, it too canlead to a long-term reduction in bloodpressure.


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Blood Volume

Endurance training increase blood volume.While plasma volume accounts for themajority of the increase, a greater productionof red blood cells can also a contributoryfactor.

Hematocrit is the concentration ofhemoglobin per unit of blood. An increase inred blood cells should increase hematocrit butthis is not the case. Because blood plasmaincreases to a greater extent than red bloodcells, hematocrit actually reduces followingtraining


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Athlete Normal


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Adaptations of the Cardivascular System to long term