Course Contents

Section 1 Exercise and the cardiovascular system

1.1 Structure and function of the cardiovascular system

1.2 Pathology of cardiovascular diseases (CVD)

1.3 Role of exercise in prevention and treatment of CVD

Section 2 Exercise and Metabolism

2.1 Energy

2.2 Body composition & Weight Control

2.3 Diabetes Mellitus

2.4 Osteoporosis

BHF Survey, 2007

Scottish Stats

Deaths from CHD

The CVS is subject to disease processes e.g.

Atherosclerosis & hypertension are disease processes that lead to the development of :

Structure/ Function of CVS Structure/ Function of CVS 2 parts:2 parts:

PumpPump VesselsVessels

HeartHeart Double pumpDouble pump

Right side – pumps to lungs (pulmonary Right side – pumps to lungs (pulmonary circulation)circulation)

Left side – pumps to body (systemic Left side – pumps to body (systemic circulationcirculation

Left side > right side Left side > right side Heart Valves prevent backflow of bloodHeart Valves prevent backflow of blood Coronary arteries supply heart muscle Coronary arteries supply heart muscle

with blood (food & oxygen)with blood (food & oxygen)

Heart Heart external viewexternal view

TRICUSPID VALVE

BICUSPID (mitral) VALVE

SEMILUNAR VALVE

Heart & Blood SupplyHeart & Blood Supply Pulmonary artery – deoxygenated bloodPulmonary artery – deoxygenated blood Pulmonary vein – oxygenatedPulmonary vein – oxygenated Coronary arteries – supply heartCoronary arteries – supply heart

Coronary veins – drain into the right atriumCoronary veins – drain into the right atrium

Aorta - blood to body (from L. ventricle)Aorta - blood to body (from L. ventricle) Vena cava (sup./ inf.) - drain body (into Vena cava (sup./ inf.) - drain body (into

R atrium)R atrium)

N.B. Hepatic Portal Vein

does not return blood to heart.

Supplies liver with products of digestion.

Important in first pass metabolism

– allowing toxins to be broken down before systemic circulation

Heart BeatHeart Beat Heart beat is endogenous (continues to beat if removed Heart beat is endogenous (continues to beat if removed

from body)from body) Rhythmical contraction of musclesRhythmical contraction of muscles Under nervous/ hormonal controlUnder nervous/ hormonal control

Influence strength & frequency of contractionInfluence strength & frequency of contraction

Heart beat originates in SinoAtrial nodeHeart beat originates in SinoAtrial node Max. rate limited (refractory period)Max. rate limited (refractory period) AV node collects signal and initiates ventricular contraction via AV node collects signal and initiates ventricular contraction via

Bindle of His after a short delay.Bindle of His after a short delay. In disease, arrythmia can develop in damaged tissueIn disease, arrythmia can develop in damaged tissue

Extra heart beat can occur initiated by damaged tissueExtra heart beat can occur initiated by damaged tissue Heart beat signal propagated through heart by bundle of His Heart beat signal propagated through heart by bundle of His

(atria – ventricles), & Purkinje fibres (nerves through muscle (atria – ventricles), & Purkinje fibres (nerves through muscle tissue)tissue)

Heart SoundsHeart Sounds StethoscopeStethoscope

Listen to heart soundsListen to heart sounds Lub dub (closing of valves)Lub dub (closing of valves)

Lub – closure of AV valvesLub – closure of AV valves Dub – closure of semilunar valvesDub – closure of semilunar valves

Diagnostic of valvular diseaseDiagnostic of valvular disease Leaky – indistinct lub/ dubLeaky – indistinct lub/ dub

Heart & ECGHeart & ECG ECG is a record of the electrical ECG is a record of the electrical

signals producing the heart beatsignals producing the heart beat ECG= ECG= EElectrolectroCCardioardioGGramram

Used diagnostically to show heart Used diagnostically to show heart problemsproblems

Cardiac CycleCardiac Cycle DIASTOLE DIASTOLE (relaxed phase)(relaxed phase) Venous filling of atriaVenous filling of atria

Atria distendAtria distend Some passive flow into ventriclesSome passive flow into ventricles

SYSTOLE SYSTOLE (contractile phase)(contractile phase) SA initiates atrial contraction SA initiates atrial contraction Blood expelled from atria into ventriclesBlood expelled from atria into ventricles Bundle of His conducts excitation to ventricles/ Bundle of His conducts excitation to ventricles/

propagated rapidly by Purkinje fibrespropagated rapidly by Purkinje fibres Ventricle contracts expels blood into arteriesVentricle contracts expels blood into arteries Contraction ends, relaxes (refractory period)Contraction ends, relaxes (refractory period)

Blood VesselsBlood Vessels ArteriesArteries Must withstand high pressureMust withstand high pressure

Thick walledThick walled Mainly elastic fibres near heartMainly elastic fibres near heart

Stretch to absorb pressure of blood expelled by heartStretch to absorb pressure of blood expelled by heart At diastole stretched arteries relax so maintain blood flow At diastole stretched arteries relax so maintain blood flow

(120/80 mmHg)(120/80 mmHg) Arteries more distant from heart less elastic fibres/ Arteries more distant from heart less elastic fibres/

more muscle (under nervous control)more muscle (under nervous control) Muscles regulate blood flow into capillary bedsMuscles regulate blood flow into capillary beds

Arteries lead to arteriolesArteries lead to arterioles Can have pre-capillary sphincters to completely close Can have pre-capillary sphincters to completely close

blood flow e.g to skin in coldblood flow e.g to skin in cold

Blood VesselsBlood Vessels CapillariesCapillaries

Wall single cell thickWall single cell thick Allows exchange of soluble Allows exchange of soluble

substancessubstances No cell more than few cell widths No cell more than few cell widths

from a capillaryfrom a capillary Diffusion rapid over these short Diffusion rapid over these short

distancesdistances

Blood vesselsBlood vessels VeinsVeins

Less muscle/ elastic fibre than arteriesLess muscle/ elastic fibre than arteries FloppyFloppy Low pressure in vein – requires valves Low pressure in vein – requires valves

to stop backflowto stop backflow Muscle pumping in calves helps venous Muscle pumping in calves helps venous

return (Economy Class Syndrome)return (Economy Class Syndrome)

                             

                

                                                               

Blood PressureBlood Pressure High arterial blood pressure (80-High arterial blood pressure (80-

120 mmHg (systolic/ diastolic)120 mmHg (systolic/ diastolic) Rapid fall in BP in arterioles/ Rapid fall in BP in arterioles/

capillariescapillaries Very low BP in veinsVery low BP in veins

Blood PressureBlood Pressure BP quoted as Systolic / diastolicBP quoted as Systolic / diastolic

Measure with a sphygmomanometerMeasure with a sphygmomanometer Block all blood flowBlock all blood flow Slowly release pressureSlowly release pressure Systoliic BP = pressure when sound of Systoliic BP = pressure when sound of

artery closing (snap) is heardartery closing (snap) is heard Diastolic BP = pressure when all Diastolic BP = pressure when all

noises stopnoises stop

Summary of StructureSummary of Structure

Cardiovascular DiseaseCardiovascular Disease CVD sCVD s

Coronary Heart disease

Angina pectoris

Myocardial infarction

Cerebrovascular disease

Stroke (cerebrovascular accident (CVA))

Cardiovascular disease Cardiovascular disease pathologypathology

Two major pathological processes lead to Two major pathological processes lead to CVDCVD AtherosclerosisAtherosclerosis

Narrowing & hardening of arteries (claudication/ angina)Narrowing & hardening of arteries (claudication/ angina) Damage to endothelium Damage to endothelium

– promotes blood clot formationpromotes blood clot formation blocking arteries – thrombosis/ embolismblocking arteries – thrombosis/ embolism

HypertensionHypertension Prolonged, elevated blood pressureProlonged, elevated blood pressure

– Primary – no known causePrimary – no known cause– Secondary – caused by pathologySecondary – caused by pathology

Kidney diseaseKidney disease Phaeochromacytoma (excess epinephrine produced)Phaeochromacytoma (excess epinephrine produced)

Typically starts in childhood, progresses in Typically starts in childhood, progresses in adulthood.adulthood.

Damage to the arterial wall caused by e.g.Damage to the arterial wall caused by e.g. elevated levels of cholesterol and triglyceride in elevated levels of cholesterol and triglyceride in

the blood the blood high blood pressure. high blood pressure. tobacco smoke tobacco smoke diabetes  diabetes 

AtherosclerosisAtherosclerosis

AtherosclerosisAtherosclerosis Fat accumulates under inner lining of Fat accumulates under inner lining of

arteriesarteries As disease progresses, fibrous material / As disease progresses, fibrous material /

calcium/ lipids (inc. cholesterol) calcium/ lipids (inc. cholesterol) accumulates (atheroma)accumulates (atheroma)

Bulges into lumen of vesselBulges into lumen of vessel Starts to reduce diameter of arteryStarts to reduce diameter of artery

Restricts blood flowRestricts blood flow Reduces elasticity of arterial wallReduces elasticity of arterial wall Can lead to high blood pressureCan lead to high blood pressure

AtherosclerosisAtherosclerosis Progression accelerated by:Progression accelerated by:

High blood cholesterol (especially LDL or "bad" High blood cholesterol (especially LDL or "bad" cholesterol over 100 mg/dL) cholesterol over 100 mg/dL)

Cigarette smoking and exposure to tobacco Cigarette smoking and exposure to tobacco smoke smoke

High blood pressure High blood pressure Diabetes mellitus Diabetes mellitus Obesity Obesity Physical inactivity Physical inactivity

Cholesterol & CVDCholesterol & CVD

Cholesterol – steroidCholesterol – steroid– Cell membranes, hormones, bile saltsCell membranes, hormones, bile salts

Most cholesterol in blood is synthesised by liverMost cholesterol in blood is synthesised by liver Dietary cholesterol acts to suppress liver Dietary cholesterol acts to suppress liver

biosynthesisbiosynthesis Dietary cholesterol NOT important risk factor Dietary cholesterol NOT important risk factor

for CVD (overall cholesterol should be less for CVD (overall cholesterol should be less than 200mg/dl)than 200mg/dl)

Saturated fats (animal) are used by liver Saturated fats (animal) are used by liver to produce cholesterolto produce cholesterol

High dietary saturated fat INCREASES High dietary saturated fat INCREASES blood cholesterol levels!! blood cholesterol levels!!

Cholesterol & CVDCholesterol & CVD

Cholesterol – insoluble in bloodCholesterol – insoluble in blood Transported attached to a protein LIPOPROTEINTransported attached to a protein LIPOPROTEIN

Two types of LIPOPROTEINTwo types of LIPOPROTEIN HDL – High density lipoproteinHDL – High density lipoprotein LDL – Low density lipoproteinLDL – Low density lipoprotein

HDL – transports cholesterol to liver for destructionHDL – transports cholesterol to liver for destruction

GOODGOOD LDL – transports cholesterol to body cells for deposition LDL – transports cholesterol to body cells for deposition

BADBAD In abnormal circumstances LDL will deposit cholesterol in In abnormal circumstances LDL will deposit cholesterol in

arteriesarteries

Cholesterol & CVDCholesterol & CVD

LDL (bad) – 60-70% blood LDL (bad) – 60-70% blood cholesterolcholesterol As LDL increases risk of atherosclerosis As LDL increases risk of atherosclerosis

increasesincreases HDL (good) – 20-30% blood HDL (good) – 20-30% blood

cholesterolcholesterol AS HDL increases risk of atherosclerosis AS HDL increases risk of atherosclerosis

decreasesdecreases Risk of CHD is predicted from HDL:LDL ratioRisk of CHD is predicted from HDL:LDL ratio High HDL (40mg/dl or more):LDL is GOODHigh HDL (40mg/dl or more):LDL is GOOD Exercise, low fat diet, not smoking improve Exercise, low fat diet, not smoking improve

HDL:LDL ratioHDL:LDL ratio

Atherosclerosis – Heart - Atherosclerosis – Heart - APAP Narrowing of coronary arteries leads to Narrowing of coronary arteries leads to

ischaemia (inadequate blood flow)ischaemia (inadequate blood flow) Pain - angina pectoris (AP) due to ischaemia Pain - angina pectoris (AP) due to ischaemia

in heart musclein heart muscle AP only during exertion of heart (when OAP only during exertion of heart (when O22

needs are high)needs are high) Glycerol trinitrite tablets release Nitric oxide Glycerol trinitrite tablets release Nitric oxide

(dilates blood vessels)(dilates blood vessels) Angioplasty/ StentsAngioplasty/ Stents Bypass surgeryBypass surgery

Atherosclerosis – EmbolismAtherosclerosis – Embolism Clots Clots

thrombus-attachedthrombus-attached embolus-travelling embolus-travelling

Embolus/ thrombus can cause blood supply to a Embolus/ thrombus can cause blood supply to a region of the heart muscle (myocardium) to region of the heart muscle (myocardium) to become blocked, causing myocardial infarctionbecome blocked, causing myocardial infarction

Thrombosis/ embolus may occur in cerebral Thrombosis/ embolus may occur in cerebral artery – stroke (cerebrovascular accident-CVA)artery – stroke (cerebrovascular accident-CVA)

or lungs pulmonary embolusor lungs pulmonary embolus

Myocardial InfarctionMyocardial Infarction

Myocardial infarction – MI (death of heart Myocardial infarction – MI (death of heart tissue)tissue) Caused by a sudden blockage to a coronary artery.Caused by a sudden blockage to a coronary artery.

Due thrombosis/ embolisDue thrombosis/ embolis Atherosclerosis (may cause angina symptoms) leads to Atherosclerosis (may cause angina symptoms) leads to

increased likelihood that thombosis will occur.increased likelihood that thombosis will occur. Causes pain (15 min) in arm, neck, jaw; nausea.Causes pain (15 min) in arm, neck, jaw; nausea. If large artery blocked – collapse, sudden deathIf large artery blocked – collapse, sudden death Tissue dies forming a scar, can cause:Tissue dies forming a scar, can cause:

Heart failure (weak pumping action)Heart failure (weak pumping action) Arrythmia, irregular contractionArrythmia, irregular contraction Cardiac arrest – ventricular fibrillationCardiac arrest – ventricular fibrillation

HypertensionHypertension Persistently high resting blood Persistently high resting blood

pressure e.g. diastolic >90mmHg pressure e.g. diastolic >90mmHg (normal 120/80; high 140/90)(normal 120/80; high 140/90)

Often caused by atherosclerosis Often caused by atherosclerosis leading to narrowing of arteries or leading to narrowing of arteries or loss of elasticityloss of elasticity Risk factor for majority of CVDs (incl. Risk factor for majority of CVDs (incl.

CHD)CHD)

Hypertension – risk factorsHypertension – risk factors Diet (high salt Diet (high salt

(Na(Na++), high fat)), high fat) SmokingSmoking ObesityObesity Genetic Genetic

predispositionpredisposition StressStress

Nicotine Nicotine (vasoconstrictor)(vasoconstrictor)

Risk Factors for CVD- SQARisk Factors for CVD- SQA ModifiableModifiable

Diet, Smoking, Activity, ObesityDiet, Smoking, Activity, Obesity

Non modifiableNon modifiable Age, Gender, Race, HeredityAge, Gender, Race, Heredity

Risk factors SummaryRisk factors SummaryWhat other factors contribute to heart disease risk?

•The risk of heart disease in people who drink moderate amounts of alcohol (an average of one drink for women or two drinks for men per day) is lower than in nondrinkers. One drink is defined as 1-1/2 fluid ounces (fl oz) of 80-proof spirits (such as bourbon, Scotch, vodka, gin, etc.), 1 fl oz of 100-proof spirits, 4 fl oz of wine or 12 fl oz of beer. It's not recommended that nondrinkers start using alcohol or that drinkers increase the amount they drink. Tobacco smoke 

• Smokers' risk of developing coronary heart disease is 2–4 times that of nonsmokers. • risk factor for sudden cardiac death: about twice the risk of nonsmokers.• Exposure to other people's smoke increases the risk of heart disease even for nonsmokers.

High blood cholesterol As blood cholesterol rises, so does risk of coronary heart

disease.When other risk factors (such as high blood pressure and tobacco smoke) are present, this risk increases even more.

A person's cholesterol level is also affected by age, sex, heredity and diet.

High blood pressure High blood pressure increases the heart's workload, causing

the heart to thicken and become stiffer. It also increases your risk of stroke, heart attack, kidney failure

and congestive heart failure. When high blood pressure exists with obesity, smoking, high

blood cholesterol levels or diabetes, the risk of heart attack or stroke increases several times.

Physical inactivity Regular, moderate-to-vigorous physical activity helps prevent

heart and blood vessel disease. The more vigorous the activity, the greater your benefits. Physical activity can help control blood cholesterol, diabetes and

obesity, as well as help lower blood pressure in some people.

•Obesity and overweight —

•People who have excess body fat — especially if a lot of it is at the waist — are more likely to develop heart disease and stroke even if they have no other risk factors.

•Excess weight increases the heart's work. It also raises blood pressure and blood cholesterol and triglyceride levels, and lowers HDL ("good") cholesterol levels.

•It can also make diabetes more likely to develop. Many obese and overweight people may have difficulty losing weight. But by losing even as few as 10 pounds, you can lower your heart disease risk.

•Diabetes mellitus — •Diabetes seriously increases your risk of developing cardiovascular disease. •risks are even greater if blood sugar is not well controlled. •About three-quarters of people with diabetes die of some form of heart or blood vessel disease.

Exercise & CVSExercise & CVS Cardiovascular system (CVS) delivers Cardiovascular system (CVS) delivers

oxygen & nutrients to body tissues, oxygen & nutrients to body tissues, removes wastesremoves wastes

During exercises more ODuring exercises more O22 & nutrients required by & nutrients required by exercising tissues (muscles), wastes removedexercising tissues (muscles), wastes removed

Exercise effects Cardiovascular system Exercise effects Cardiovascular system functionfunction

Cardiac output increasedCardiac output increased Circulation redistributed to important tissuesCirculation redistributed to important tissues

Cardiac OutputCardiac Output Cardiac output (C.O.) = volume of Cardiac output (C.O.) = volume of

blood pumped per min. by the blood pumped per min. by the heartheart

Regulated by:Regulated by:– Heart rate (H.R.)Heart rate (H.R.)– Stroke volume (S.V.)Stroke volume (S.V.)

C.O. = H.R. x S.V.C.O. = H.R. x S.V.

Exercise effects on HeartExercise effects on Heart Exercise causes HR & SV to Exercise causes HR & SV to

increase i.e. COincrease i.e. CO Meets needs of musclesMeets needs of muscles

Athlete’s HeartAthlete’s Heart

Regular exercises strengthens heart muscleRegular exercises strengthens heart muscle Ventricular mass (echocardiography) increases (210-300g)Ventricular mass (echocardiography) increases (210-300g)

FForce of contraction orce of contraction , more blood expelled per beat (SV , more blood expelled per beat (SV ))

Ventricular volume also increases (100-180ml)Ventricular volume also increases (100-180ml) (SV (SV )) Consequently HR at rest of a trained athlete Consequently HR at rest of a trained athlete (Bjorn Borg – 32bpm, Miguel Induraine, 29bpm)(Bjorn Borg – 32bpm, Miguel Induraine, 29bpm)

CO of trained heart increased so more OCO of trained heart increased so more O22 and food and food delivered at max. HRdelivered at max. HR Therefore max. level of activity greaterTherefore max. level of activity greater

Redistribution of Blood Redistribution of Blood flowflow During exercise blood flow directed During exercise blood flow directed

away from non-essential needs away from non-essential needs (gut, kidney)(gut, kidney)

Redirected to heart, muscles, skin Redirected to heart, muscles, skin (cooling)(cooling)

Vasodilation/ vasoconstriction of Vasodilation/ vasoconstriction of supplies to these tissues.supplies to these tissues.

Exercise & Blood PressureExercise & Blood Pressure Cardiac Output increased (HR/ SVCardiac Output increased (HR/ SV))

Tends to increase BPTends to increase BP Vasodilation of blood supply to Vasodilation of blood supply to

musclesmuscles Increases volume of vascular systemIncreases volume of vascular system Peripheral vascular resistance reducedPeripheral vascular resistance reduced Tends to reduce BPTends to reduce BP

Overall slight increase in BPOverall slight increase in BP Systolic increase > diastolicSystolic increase > diastolic

Exercise & HypertensionExercise & Hypertension

Regular exercise, produces long Regular exercise, produces long term, moderate fall in BPterm, moderate fall in BP

Offsets age related hardening of Offsets age related hardening of arteriesarteries

Acutely, a fall in BP is also found Acutely, a fall in BP is also found following exercise.following exercise.

Role of exerciseRole of exercise- in preventing CVD- in preventing CVD

Decreases a number of risk factors:Decreases a number of risk factors: HDL HDL , LDL , LDL Resting HR Resting HR Arterial blood pressure Arterial blood pressure Body fat Body fat (i.e. obesity (i.e. obesity )) Reduces development of atheromaReduces development of atheroma Reduces stressReduces stress

Moderate exercise 3-5 times per week Moderate exercise 3-5 times per week lasting more than 20minslasting more than 20mins

Exercise testing - Exercise testing - IntroductionIntroduction Monitor recovery from MIMonitor recovery from MI Monitor improvement in athletic Monitor improvement in athletic

training programmetraining programme Measure aerobic capacityMeasure aerobic capacity Assess performance of respiratory Assess performance of respiratory

and cardiovascular systems in and cardiovascular systems in delivering oxygendelivering oxygen

Exercise testing - Exercise testing - PrinciplesPrinciples Oxygen required by body to workOxygen required by body to work Maximum work rate – determined by Maximum work rate – determined by

body’s ability to deliver oxygen to bodybody’s ability to deliver oxygen to body VOVO2max2max – maximal oxygen uptake – maximal oxygen uptake

Higher the VOHigher the VO2max2max, the greater the aerobic , the greater the aerobic fitnessfitness

Measure by exercising to exhaustion Measure by exercising to exhaustion and directly measure Oand directly measure O22 uptake and CO uptake and CO22 ouputouput

Exercise testing – Direct Exercise testing – Direct MethodMethod Treadmill/ bicycle ergometerTreadmill/ bicycle ergometer

Using online gas analysisUsing online gas analysis Progressively increase workload until Progressively increase workload until

no further increase in Ono further increase in O22 consumption consumption i.e. exercise to exhaustioni.e. exercise to exhaustion Oxygen consumption at that point = Oxygen consumption at that point =

VOVO2max2max

Suitable for fit peopleSuitable for fit people

Exercise testing – Indirect Exercise testing – Indirect MethodMethod Shuttle testShuttle test

Run between two cones (20m apart)Run between two cones (20m apart) Rate determined by a tape (beep)Rate determined by a tape (beep) Subject continues until they can’t Subject continues until they can’t

maintain pacemaintain pace Number of completed shuttles can Number of completed shuttles can

be used to predict VObe used to predict VO2max2max

Exercise Testing – Sub Exercise Testing – Sub maximal maximal If exercise to exhaustion clinically contra-If exercise to exhaustion clinically contra-

indicatedindicated Submaximal testing usedSubmaximal testing used Patient OPatient O22 consumption measured at consumption measured at

various levels of work intensity various levels of work intensity (submaximal)(submaximal)

Graph of OGraph of O22 consumption vs. HR plotted consumption vs. HR plotted Theoretical max. HR calculated (220-age)Theoretical max. HR calculated (220-age) Graph extrapolated to estimate theoretical Graph extrapolated to estimate theoretical

max. Omax. O22 consumption consumption

Exercise Testing – Sub Exercise Testing – Sub maximal maximal Assumptions:Assumptions:

Direct relation between HR and ODirect relation between HR and O22 consumption and intensity of exerciseconsumption and intensity of exercise

Sources of error:Sources of error: HR affected by other factors:HR affected by other factors:

– EmotionEmotion– TemperatureTemperature– AnxietyAnxiety

Predicted HR may be inaccurate for a given Predicted HR may be inaccurate for a given individualindividual

Exercise Stress TestingExercise Stress Testing Used to diagnose heart Used to diagnose heart

abnormality only present under abnormality only present under stressed conditionsstressed conditions

Bruce ProtocolBruce Protocol Treadmill speed/gradient increased Treadmill speed/gradient increased

incrementallyincrementally Exercise to exhaustionExercise to exhaustion

ECG can be monitored to evaluate ECG can be monitored to evaluate effect of exercise on hearteffect of exercise on heart