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Cardiovascular Physiology
PHYE 280: Exercise Physiology
Kevin Petti, Ph.D.Departments of Natural Sciences,
Health, Exercise Science and NutritionSan Diego Miramar College
Objectives
Identify the four components of fitness
Identify basic heart anatomy and blood flow
Understand the following cardiodynamicvariables: systole, diastole, stroke volume,cardiac output, ejection fraction, the cardiacconducting system, blood pressure, andvenous return
Describe how these adapt to exercise
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Components of Fitness
Cardiorespiratory Endurance Ability of heart, lungs and blood vessels to deliver O2 to
exercising muscles
Muscular Strength Maximum amount of force a muscle can exert during a
single contraction
Flexibility Range of Movement (ROM) at a joint
Body Composition High lean mass or fat-free mass (muscle and bone) Low fat mass
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Basic Cardiac Anatomy
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The Coronary Arteries
Right
Left Anterior
Descending
Circumflex
Valves of the Heart
Atrioventricular Valves Tricuspid Valve
Between RA and RV
Bicuspid/Mitral Valve Between LA and LV
Semilunar Valves Pulmonary Valve
Aortic Valve
Chordae tendineae andpapillary musclesassociated w/ AV Valves
Valves prevent theregurgitation of blood
Valves open and close viachanges in chamber BP
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Cardiac Physiology Concepts
Conducting System of the Heart Electrocardiogram (ECG) Cardiodynamics
EDV, ESV, SV, EJ, Q
Cardiac Output At rest vs. exercise Trained vs. untrained
Blood Pressure
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Conducting System of the Heart
The heart is autorhythmic beats w/o nervous stimulation The cells responsible for initiating and distributing
the stimulus for cardiac contraction are the heartsconducting system
Comprised of Sinoartial (SA) Node Atrioventricular (AV) Node Conducting Cells
AV Bundle Bundle Branches (Bundle of His) Purkinje Fibers
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The Electrocardiogram (ECG)
Systole - chamber contraction Diastole - chamber relaxation
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Cardiodynamics
End-Diastolic Volume (EDV) Volume of blood in each ventricle at the end of
ventricular diastole
End-Systolic Volume (ESV) Volume of blood in each ventricle at the end of
ventricular systole
Stroke Volume (SV) Amount of blood ejected from each ventricle per beat Can be expressed as EDV - ESV = SV
Ejection Fraction Percentage of EDV ejected in ventricular systole
Cardiodynamics
Cardiac Output Amount of blood ejected from each ventricle in
one minute Perhaps the most important variable of cardiac
function Can be expressed as below:Q = Hr x SVCardiac Heart StrokeOutput Rate Volume(ml/min) (beats/min) (ml/beat)
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Cardiac Output at Rest
Q = Hr x SVCardiac Heart StrokeOutput Rate Volume(ml/min) (beats/min) (ml/beat)
6000 ml/min = 75 bpm x 80 ml/beator 6 l/min
Cardiac Output at rest equals 6 liters/minuteAverage adult has 5 liters of blood
Cardiac Output During Exercise
Q = Hr x SVCardiac Heart StrokeOutput Rate Volume(ml/min) (beats/min) (ml/beat)
13,440 ml/min = 120 bpm x 112 ml/beator 13.4 l/min
Cardiac Output can more than double during moderate exercisefor the average adult
Elite athletes can have Cardiac Outputs in excess of 25 l/min!180 bpm x 160 ml/beat = 28.8 l/min
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Cardiac Output Adaptations inResponse to Aerobic Training
Resting heart rate decreases as a result of increasedfitness
What would this do to SV if Q remains constant?
This answer is a result of Starlings Law that statesEDV = SV
SV with training, so what happens to exercisingHR at a particular intensity (10 min. mile) as onebecomes more trained?
Factors Affecting Stroke Volume
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Factors Affecting Cardiac Output
Blood Pressure
Systemic arterial pressure Measured in mm Hg millimeters of mercury Declines further from heart
Mean Arterial Pressure (MAP) is most often used instudies reporting a single blood pressure 1/3 of pulse pressure (systolic-diastolic) + diastolic pressure
Regulated closely by neural and hormonalmechanisms; is a function of resistance to blood flow
Resistance is a function of vessel diameter, vessellength, blood viscosity, blood turbulence
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Measuring Blood Pressuresystolic/diastolic
Blood Pressure
Resting BP120/80 mmHg
MAP =
93.3mm Hg
Exercising MAPcan exceed113 mmHg(200/70)
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Blood Pressureand Venous Return
BP at start of venous system is 1/10 of that at startof arterial system
BP at right atrium is only 2 mm Hg!
Venous return is assisted by muscular compression,and the respiratory pump
Both of these are extremely important duringexercise Why is it important to cool down after aerobic exercise?
