circulatory adaptations to exercise
DESCRIPTION
Chapter 9. Circulatory Adaptations to Exercise. The Cardiovascular System. Components Circulatory system Pulmonary system Purposes Transport O 2 to tissues and removal of other products (“waste”) Transport of nutrients to tissues Regulation of body temperature. The Circulatory System. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/1.jpg)
Circulatory Adaptations to Exercise
Chapter 9
![Page 2: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/2.jpg)
The Cardiovascular System
Components– Circulatory system – Pulmonary system
Purposes– Transport O2 to tissues and removal of
other products (“waste”)– Transport of nutrients to tissues– Regulation of body temperature
![Page 3: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/3.jpg)
The Circulatory System
Heart– Pumps blood
Arteries and arterioles– Carry blood away from the heart
Capillaries– Exchange of materials with tissues
Veins and venules– Carry blood toward the heart
![Page 4: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/4.jpg)
Structure of the Heart
![Page 5: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/5.jpg)
Pulmonary and Systemic Circuits
Systemic circuit– Left side of the heart– Pumps oxygenated
blood to the whole body via arteries
– Returns “deoxygenated” blood to the right heart via veins
Pulmonary circuit– Right side of the
heart– Pumps “deoxygen-
ated” blood to the lungs via pulmonary arteries
– Returns oxygenated blood to the left heart via pulmonary veins
![Page 6: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/6.jpg)
The Myocardium
![Page 7: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/7.jpg)
The Cardiac Cycle
Systole– Contraction phase
Diastole– Relaxation phase
![Page 8: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/8.jpg)
Pressure Changes During the Cardiac Cycle
![Page 9: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/9.jpg)
Arterial Blood Pressure
Expressed as systolic/diastolic– Normal is 120/80 mmHg– High is 140/90 mmHg
Systolic pressure (top number)– Arterial pressure during systole
Diastolic pressure– Arterial Pressure during diastole
![Page 10: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/10.jpg)
Arterial Blood Pressure
Pulse pressure– Difference between systolic and diastolic
Pulse Pressure = Systolic - Diastolic
MAP = Diastolic + 1/3(Systolic - Diastolic)
Mean arterial pressure (MAP)– Average pressure in the arteries
![Page 11: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/11.jpg)
Measurement of Blood Pressure
![Page 12: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/12.jpg)
Factors That Influence Arterial Blood Pressure
![Page 13: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/13.jpg)
Electrical Activity of the Heart
Contraction of the heart depends on electrical stimulation of the myocardium
Impulse is initiated by the SA node and spreads throughout entire heart
May be recorded on an electrocardiogram (ECG or EKG)
![Page 14: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/14.jpg)
Conduction System of the Heart
![Page 15: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/15.jpg)
Electrocardiogram
![Page 16: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/16.jpg)
Electrocardiogram
Records the electrical activity of the heart P-wave
– Atrial depolarization QRS complex
– Ventricular depolarization T-wave
– Ventricular repolarization
![Page 17: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/17.jpg)
Diagnostic Use of the ECG
ECG abnormalities may indicate coronary heart disease– ST-segment depression can indicate
myocardial ischemia (reduced blood flow)
![Page 18: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/18.jpg)
Abnormal ECG Response to Exercise
![Page 19: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/19.jpg)
Cardiac Output
The amount of blood pumped by the heart each minute
Product of heart rate and stroke volume– Heart rate = number of beats per minute– Stroke volume = amount of blood ejected
from the heart in each beat
.Q = HR x SV
![Page 20: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/20.jpg)
Regulation of Heart Rate
Decrease in HR– Parasympathetic nervous system
• Via vagus nerve
– Slows HR by inhibiting SA node Increase in HR
– Sympathetic nervous system• Via cardiac accelerator nerves
– Increases HR by stimulating SA node
![Page 21: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/21.jpg)
A Summary of Cardiovascular Control During Exercise: Fine Tuning
![Page 22: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/22.jpg)
Nervous System Regulation of HR
![Page 23: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/23.jpg)
Regulation of Stroke Volume
End-diastolic volume (EDV)– Volume of blood in the ventricles at the end
of diastole (“preload”) Average aortic blood pressure
– Pressure the heart must pump against to eject blood (“afterload”)
Contractility – Strength of the ventricular contraction
![Page 24: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/24.jpg)
Incremental Exercise
Heart rate and cardiac output– Increases linearly with increasing work rate
– Reaches plateau at 100% VO2max
Systolic blood pressure– Increases with increasing work rate
Double product– Increases linearly with exercise intensity– Indicates the work of the heart
Double product = heart rate x systolic BP
![Page 25: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/25.jpg)
End-Diastolic Volume
Frank-Starling mechanism– Greater preload results in stretch of ventricles
and in a more forceful contraction Affected by:
– Venoconstriction– Skeletal muscle pump– Respiratory pump
![Page 26: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/26.jpg)
The Skeletal Muscle Pump
Rhythmic skeletal muscle contractions force blood in the extremities toward the heart
One-way valves in veins prevent backflow of blood
![Page 27: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/27.jpg)
The Skeletal Muscle Pump
![Page 28: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/28.jpg)
Average Aortic Pressure
Aortic pressure is inversely related to stroke volume
High after load results in a decreased stroke volume– Requires greater force generation by the
myocardium to eject blood into the aorta Reducing after load results in higher
stroke volume
![Page 29: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/29.jpg)
Ventricular Contractility
Increased contractility results in higher stroke volume
Causes:– Circulating epinephrine and norepinephrine– Direct sympathetic stimulation of heart
![Page 30: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/30.jpg)
Hemodynamics
Flow of blood through the circulatory system
Based on interrelationships between:– Pressure– Resistance– Flow
![Page 31: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/31.jpg)
Components of Blood
![Page 32: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/32.jpg)
Hemodynamics: Resistance
Resistance depends upon:– Length of the vessel– Viscosity of the blood– Radius of the vessel
• A small change in vessel diameter can have a dramatic impact on resistance!
Resistance = Length x viscosity
Radius4
![Page 33: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/33.jpg)
Hemodynamics: Blood Flow
Directly proportional to the pressure difference between the two ends of the system
Inversely proportional to resistance
Flow = Pressure
Resistance
![Page 34: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/34.jpg)
Sources of Vascular Resistance
MAP decreases throughout the systemic circulation
Largest drop occurs across the arterioles– Arterioles are called “resistance vessels”
![Page 35: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/35.jpg)
Pressure Changes Across the Systemic Circulation
![Page 36: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/36.jpg)
Oxygen Delivery During Exercise
Oxygen demand by muscles during exercise is many times greater than at rest
Increased O2 delivery accomplished by:
– Increased cardiac output– Redistribution of blood flow to skeletal
muscle
![Page 37: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/37.jpg)
Changes in Cardiac Output
Cardiac output increases due to:– Increased HR
• Linear increase to max after 120 bpm
– Increased SV• Plateau at ~40% VO2max
Max HR = 220 - Age (years)
.
![Page 38: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/38.jpg)
Changes in Cardiovascular Variables During Exercise
![Page 39: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/39.jpg)
Redistribution of Blood Flow
Increased blood flow to working skeletal muscle
Reduced blood flow to less active organs– Liver, kidneys, GI tract
![Page 40: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/40.jpg)
Changes in Muscle and Splanchnic Blood Flow During Exercise
![Page 41: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/41.jpg)
Redistribution of Blood Flow During Exercise
![Page 42: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/42.jpg)
Circulatory Responses to Exercise Heart rate and blood pressure Depend on:
– Type, intensity, and duration of exercise– Environmental conditions– Emotional influence
![Page 43: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/43.jpg)
Transition From Rest Exercise and Exercise Recovery Increase in HR, SV, cardiac output Plateau in sub maximal exercise Recovery depends on:
– Duration and intensity of exercise– Training state of subject
![Page 44: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/44.jpg)
Transition From Rest Exercise Recovery
![Page 45: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/45.jpg)
Incremental Exercise
Heart rate and cardiac output– Increases linearly with increasing work rate
– Reaches plateau at 100% VO2max
Systolic BP– Increases with increasing work rate
Diastolic BP– Decreases slightly then remains even
.
![Page 46: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/46.jpg)
Prolonged Exercise
Cardiac output is maintained– Gradual decrease in stroke volume– Gradual increase in heart rate
Cardiovascular drift– Due to dehydration and increased skin
blood flow (rising body temperature)
![Page 47: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/47.jpg)
HR, SV, and CO During Prolonged Exercise
![Page 48: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/48.jpg)
Summary of Cardiovascular Adjustments to Exercise
![Page 49: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/49.jpg)
Chronic Endurance Training
Stronger/ thicker/ larger left ventricle Lower resting and working HR Greater resting and working SV Lower resting and working blood
pressure– Greater capillarization which decreases
TPR – total peripheral resistance
![Page 50: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/50.jpg)
Questions?
![Page 51: Circulatory Adaptations to Exercise](https://reader036.vdocuments.us/reader036/viewer/2022062500/56814fcd550346895dbd8f6e/html5/thumbnails/51.jpg)
END