cardio-respiratory system Flashcards
respiratory system
primary is to exchange oxygen for carbon dioxide.
process controlled by lungs - affected by muscles that can act both voluntarily and involuntarily. mostly involuntary
atmospheric air
the air around the body which is used for breathing
differences between composition of atmospheric air and the air we breath out
expired air contains less oxygen than inspired air - represents that used by the aerobic energy systems.
carbon dioxide greater in expired air than inspired - represents that produced by the aerobic energy systems
even though nitrogen is used by the body for a variety of functions, its relative consumption is so small that it is considered negligible.
percentage gases inspired and expired
oxygen - inspired = 20.93% expired = 16.93%
carbon dioxide - inspired = 0.03% expired = 4.03%
nitrogen - inspired = 79.04% expired = 79.04%
functions of the lungs
lungs provide the only point of contact between blood and the external environment.
supply of oxygen to meet the tissue demands of the body
elimination of waste products - carbon dioxide
structure of lungs
av lung weighs 1kg and holds between 4-6 litres of air
if spread out the contents of the lungs would cover and entire badminton court
lungs are covered by membrane called the ‘pleural sac’ = allows inner and outer walls of lungs to slide freely over each other.
this sac also encloses each lung and divides the lungs into sections - into lobes
pulmonary ventilation
- Describes how atmospheric air moves into and exchanges with air already in lungs
- Air moves into body through nose and mouth after activation of diaphragm and intercostal muscles
- Tiny hairs and mucus in back of nose and throat filter the air
- They have 3 functions = warm, moisten and purify air before enters lungs
- Passage of air = pharynx, larynx, trachea and bronchus
- In bronchus air splits and passes into either right or left lung
- In lung bronchi split to form bronchioles which transport air to alveoli
- Oxygen enters capillaries from alveolus
- Carbon dioxide enters alveolus from capillaries
- Oxygen in blood is delivered to body tissues to fuel metabolism
- During pulmonary ventilation a percentage of gasses in alveoli and airways is not directly exchanged = dead space
gaseous exchange
- Made possible because of semipermeable capillaries and partial pressure between the 2 environments
- Capillaries are 1 cell thick so gasses and nutrients can diffuse across easily
- Partial pressure of oxygen is about 60 mmHg greater than in the pulmonary capillary which allows for the diffusion of carbon dioxide and oxygen between capillaries and alveolus
- Exercise increases speed of diffusion
- Higher pressure = higher rate of diffusion
vasalva manoeuvre
a respiratory technique that involves closing narrowest part of the trachea (glottis) following maximum inhalation to increases intrathoracic pressure.
risks of vasalva maneouvre
- increased intrathoracic and abdominal pressure impedes venous return, especially blood returning in the inferior vena cava which can often cause many thoracic veins to actually collapse
- dizziness and loss of consciousness are highly possible due to reduced venous return
- blood clots can detach = reopened wounds
- prolonged vasalva manoeuvres produced a significant and rapid drop in blood pressure
- when the glottis reopens, an overshoot in blood pressure occurs placing additional and unnecessary strain on cardiovascular system
the heart’s wall consists of 3 layers of cardiac tissue
pericardium
myocardium
endocardium
pericardium
the protective outer case of heart.
Is composed of two sacs = the outer sac provides a fibrous protective layer, and the inner sac = a double layered serum-like membrane.
when healthy these sacs act as a single structure with a thin film fluid separating them; as the heart contracts this fluid film enables the sacs to move freely alongside each other.
Myocardium
- Forms bulk of the heart
- Represents the heart’s muscular wall
- It is multinucleated
- Its fibres are structured in a lattice arrangement
- Its structure is crucial to the stimulation or depolarisation of the heart
- When one muscle cell is stimulated, the adjacent cells are also contracted causing a synchronised contraction throughout heart’s wall
- Has virtually no anaerobic ability and relies entirely on a rich supply of oxygen from coronary arteries
Endocardium
a smooth inner lining of the heart and is continuous with the large blood vessels to which the heart is connected.
respiratory control
- Typically involuntary
- Can be voluntary for short time
- Breathing is also controlled by higher centres in the brain
- A variety of other factors have the potential to indirectly influence breathing including temperature, fear, anxiety, drugs and alcohol
the mechanisms that summarise a range of factors that control respiration
the respiratory centre
chemoreceptors
the respiratory centre
- Formed by a group of nerve cells that control the rate and depth at which we breathe
- Located deep in brain stem
- They transmit motor impulses to the diaphragm and intercostal muscles to initiate breathing
- Also activate accessory respiratory muscles as required
chemoreceptors
- Respond to changes in the partial pressure of both oxygen and carbon dioxide
- Provide constant feedback to respiratory centre about oxygen and carbon dioxide levels
- When carbon dioxide levels rise, the respiratory centre is stimulated which increases rate and depth of breathing by activation respiratory muscles
the structure of the heart
- Heart has ability to regulate the strength of its own contractions
- When heart rate increases a greater volume of blood returns to heart and causes chambers to enlarge
- Which larger chambers each contraction is able to pump out more blood with each beat
- This process reverses when hr lowers
- The four chambers are classified according to their upper or lower position
- Upper chambers = atria
- Lower chambers = ventricles
- Heart divided into right and left side by a thick muscular walled called septum
bradycardia
term used to describe a resting heart rate below 60 BPM - this has potential to result in insufficient oxygenation, or ischemia, of the heart’s own muscular wall and other body tissues.
tachycardia
describes a resting HR above 100 BPM. this condition can be dangerous as diastole is significantly reduced, which lowers the efficiency of each heart beat and ultimately reduces the volume of blood and oxygen.
regulation of heart rate
- Hr is regulated intrinsically by heart’s own conduction system and extrinsically by endocrine system
- Intrinsic conduction system = pacemaker
- Pacemaker is controlled by the sinoatrial node (S-A node)
- This initiates a tiny wave of electrical impulses across wall of the atria
- This causes the atria to contract and force their content into the ventricles
- Impulses starting at the S-A node move across atria to the atrioventricular node
- This node briefly delays the contraction of the ventricles to allow them time to fill
- Then the A-V node transmits the impulse across the wall of the ventricles
- This is via a network of conducting fibres called purkinje fibres
coronary veins
remove blood and waste products from the tissues, or in this case cardiac tissues.
the coronary veins transport deoxygenated blood from the myocardium to the vena cava so that it can be transported to the lungs for re-oxygenation.
heart disease
an umbrella term to describe many conditions affecting the cardiovascular system. heart disease is the single most preventable cause of premature death in developed countries and may also be described as cardiovascular disease, coronary artery disease (CAD), coronary heart disease (CHD) and occasionally degenerative heart disease (DHD).
coronary arteries
- They arise from just about the aortic valve
- Collectively they span the heart’s surface
- They deliver nutrients and gases to network of capillaries surrounding myocardial cells
- The left coronary artery splits into left anterior descending coronary artery and left circumflex
- These deliver to the myocardium surrounding the left atrium and ventricle
- The right coronary artery delivers oxygen to the right atrium and ventricle
- The majority of blood flow through the coronary arteries towards the heart’s myocardium occurs during systole
- The uptake of oxygen and nutrients mostly takes place during diastole
systolic
blood pressure refers to the pressure in the arteries during systole, the point at which the ventricles are ejecting blood
diastolic
blood pressure describes the pressure in the arteries during diastole, the resting phase between heart beats.
those suffering from hypertension are also much more likely to develop other conditions and diseases - such as
stroke
transient ischemic attack (TIA - mini stroke)
kidney failure
coronary circulation
- This is a network of blood vessels from which the heart receives its oxygen supply
- Its function is to keep myocardium continually supplied with blood and oxygen so heart can keep supplying rest of body with nutrients.
- The myocardium has very little anaerobic capacity so is dependent on coronary arteries for oxygen
- Regular physical activity = longer diastoles and lower resting HR which increases delivery of oxygen to myocardium
atherosclerosis
- Degenerative process in which cholesterol-rich plaques called atheroma accumulate on inner lining of medium and large arteries
- This results in narrowing of the internal diameter or lumen of the artery which reduces blood flow through it
- Cholesterols that form the bulk of this plaque are usually harmful low-density lipoproteins (LDLs)
arteriosclerosis
- Process occurs when the elastic tissue in the arteries starts to waste and artery wall hardens
- This stiffening reduces its ability to dilate, esp during physical activity, which causes rapid increase in blood pressure
- Leading causes = smoking, hypertension and high cholesterol
- Being male and hereditary factors are also strongly linked
- There is a strong link between arteriosclerosis and atherosclerosis because the fatty deposits in the artery wall can initiate the hardening process
stages of atherosclerosis
healthy artery thrombus plaque forms plaque raptures blood clot forms
Ischemia
- Describes shortage of oxygen and glucose in one or more body tissues
- Commonly caused by progressed cases of atherosclerosis
- Can trigger a number of symptoms depending on affected arteries
- Eg because the myocardium is wholly dependent on oxygen, atherosclerosis in the coronary arteries can lead to ischemia in the myocardium = angina
angina
- Angina attacks are normally present during acute shortfall of oxygen
- Severe cases can be life threatening but symptoms do subside with the appropriate treatment
- If an atheroma breaks away from the internal artery wall, it can block a narrower blood vessel and restrict blood to another part of body = embolism
- When an embolism blocks one or more of the coronary arteries, it is classified as ‘myocardial infarction’ (heart attack)
risk factors for heart disease
when multiple risk factors are combined. whether primary, secondary or both, the risk that disease will develop or progress rises considerably.. those individuals that have a family history of heart disease should be especially mindful of their lifestyle-related behaviours if they want to reduce their chances of developing a diseased cardiovascular system because hereditary factors are one of the most potent determinants.
blood pressure and classification
<90 systolic/ <60 diastolic = hypotensive
90-120 systolic/ 60-80 diastolic = normal blood pressure
121-139 systolic/ 80-90 diastolic = pre-hypertensive
140-159 systolic/ 90-99 diastolic = hypertensive stage 1
160-179 systolic/ 100-109 diastolic = hypertensive stage 2
> 180 systolic/ >110 diastolic = hypertensive stage 3
other risk factors of hypertension include
family history smoking age gender - men under 45 and over 64 ethnicity sedentary lifestyle poor diet - esp rich in saturated fats, processed foods and salt overweight/obese excessive alcohol/ caffeine consumption stress and anxiety
hypotension
low blood pressure
does not ‘generally’ pose any serious health risks.
people with low blood pressure may experience periods of light headedness, dizziness and fainting, especially when moving from seated to standing positions - when persistent should seek doctor’s attention.
likely to reduce blood flow during intense exercise - which inevitably restricts a person’s exercise capacity.
blood plasma lipoproteins PLPs
- Formed by interaction of fats and proteins
- Transport fats throughout the body
- Fat is not water soluble and does not dissolve in blood plasma like other nutrients so has to bind with lipoproteins to be transported
- When greater quantities of fat are consumed, the concentration of PLPs in blood increase
- This is in order to distribute triglycerides to mitochondrion for oxidation or adipose tissue for storage
- 2 main types of lipoprotein that influence cholesterol = high-density and low-density lipoprotein
low-density lipoproteins
(LDLs)
are formed by the interaction of cholesterol and protein, which is why they have a soft and sticky composition.
often described as ‘bad cholesterol’ because they deposit themselves within the artery walls, increasing the risk of atherosclerosis, hypertension and heart disease.
high-density lipoproteins
(HDLs)
formed by the interaction of cholesterol and protein, but contain considerably more protein than cholesterol - gives them a greater density/
often described as ‘good cholesterol’ - can help to reverse atherosclerosis by removing deposited cholesterol or plaque from artery walls.
not directly related to the level of ingested dietary fats - they are manufactured by the liver and deposited into the bloodstream.
primary role of HDLs is to scavenge LDLs from the blood and return them to liver where they are converted to bile and excreted.
HDLs can also clean the artery walls of developing fatty plaques.
higher concentrations of HDLs, relative to LDLs, can help protect against CHD and its related conditions.
hypercholesterolemia
(high cholesterol)
been linked with an increased risk of cardiovascular disease (CVD) because elevated blood cholesterol increases the concentration of blood plasma lipoproteins.
most influencing factors of hypercholesterolemia
excessive dietary fat consumption obesity sedentary lifestyle smoking excessive alcohol intake diabetes - esp 2
practical approaches for people to reduce their risk of CHD
- increased participation in structured exercise at recommended frequency and intensity.
- quit smoking and/or avoid exposure to cigarette smoke
- avoid convenience foods like takeaways, sweets and ready meals.
- avoid saturated and trans fat
- consume only a small amount of foods and drinks that are high in fats and/or sugars
- reduce salt intake to recommended levels
- maintain a healthy bodyweight/ BMI
- avoid consuming too much alcohol
- drink plenty of water/dilute fluids
- avoid excessive caffeine intake
- manage stress
- ensure conditions like diabetes, hypertension or hypercholesterolaemia are managed or stable.
general health benefits of cardiovascular exercise
- improvements in everyday functions like walking, stair climbing, gardening and shopping
- decreased risk of CHD and other chronic degenerative conditions
- modest reductions in blood pressure.
- improved blood cholesterol profile
- reduces bodyfat which greatly assists in managing a healthy bodyweight
- improved self esteem
- reduces stress levels
- increases bone density in the specific areas of the skeleton loaded, esp with high impact exercise modalities.
cardiorespiratory responses to exercise
increased heart rate increased respiratory rate increased tidal volume vasodilation of the blood vessels delivering nutrients to the active tissues increased cardiac output vasoconstriction of the blood vessels that deliver nutrients to the non-active tissues. an increase in systolic blood pressure increased stroke volume increased ejection fraction
the mechanics of breathing
- The movement of air in and out of the lungs is achieved by the diaphragm and intercostal muscles
- When these muscles are activated they increase the size of the thoracic cavity which reduces the pressure in this space
- Gases always move from high to low pressure
- When pressure in lungs is less than surrounding atmosphere, air moves into lungs = gaseous exchange
- In expiration pressure in the thoracic cavity is increased because of its reduction
- Lungs do not expand and recoil themselves but are acted on inferiorly by the pull of the diaphragm and superiorly by elevation or depression of ribs
- Diaphragm becomes flatter when contracts
- Intercostal muscles are made up from several groups of muscles situated between the ribs
- At rest, the ribs are angled downwards to the spine posteriorly
- When ribs are elevated they (and the sternum) move away from the spine
- The external intercostals elevate the ribs during inspiration and the intercostals depress the ribs during expiration
- During intense exercise any muscle attached to the rib cage has the ability to assist in breathing by making rapid changes to size of thoracic cavity
- These muscles are accessory respiratory muscles
lung volumes and capacities
in normal quiet breathing there are about 15 respiratory cycles per minute, each consisting of inspiration, expiration and pause.
the lungs and airways are never empty, and because the exchange of gases takes place only across the alveolar walls, the remaining space within the respiratory passages is referred to as ‘dead space’ - this is typically about 150ml in healthy people.
tidal volume
volume of air moved into or out of lungs (approx. 500ml) when TV increases Residual Volume decreases.
Residual Volume
the volume of air remaining in the lungs following a maximum expiration - without this the lungs would collapse
Vital Capacity
this is the maximum volume of expired gases following a maximum inspiration - sometimes called ‘forced vital capacity’.
represents the maximum volume of usable air
Total Lung Capacity
maximum volume of air within the lungs represents TLC. this is measured by adding the residual volume to the vital capacity.
this is not increased by exercise - it is primarily affected by body size. exercise does increase efficiency of lungs.
alveolar ventilation
- volume of air that moves into and out of the alveoli per minute
- = tidal volume - anatomical dead space.
- exercise increases the size and number of alveoli and stimulates capillarisation around these alveoli
- both of these increase alveolar ventilation and result in greater levels of oxygen entering the bloodstream.
external respiration
- Describes exchange of gases by diffusion between alveoli and the capillary
- Sometimes called pulmonary respiration because takes place in pulmonary system
- Venous blood arrives at lungs from active tissues of the body
- Contains high levels of c02 and low levels of o2
- Co2 diffuses into alveoli at venule end of capillary until equilibrium with alveolar air is reached
(C02 = capillary to alveoli) - By same process 02 diffuses at arteriole end of capillary from alveoli
(02 = alveoli to capillary) - The narrow capillaries slow down the blood flow in this area, thereby allowing more time for diffusion to take place
internal respiration
- Exchange of gases between the systemic capillaries and body tissue cells
- Diffusion cannot occur across artery walls or veins because too thick
- This means the partial pressure of blood arriving at capillaries is the same as the blood that leaves the lungs
- It is this pressure that drives the internal respiration because the pressure of the gases in the body tissues will be lower than that in arriving blood
- Oxygenated blood arrives at capillaries and diffuses into cells of body tissue
- Simultaneously c02 diffuses into the capillary from the extracellular fluid surrounding the cell
- This takes place throughout entire body and every cell needs 02 to stay alive
the cardiovascular system
sometimes called circulatory system.
consists of heart, and blood vessels, which collectively shuttle nutrients and waste materials around the body in order to maintain homeostasis. blood circulation also contributes to thermoregulation by helping retain or dissipate heat as is required. also circulates white blood cells.
vital role of the system is maintaining life and health depends entirely on the continuous and controlled movement of the blood through the thousands of miles of capillaries that permeate every tissue to reach every cell in the body.
it is in the microscopic capillaries that blood performs its ultimate transport function. nutrients and other essential materials pass from capillary blood into fluids surrounding the cells, as waste products are removed.
increasing blood flow
during exercise, the cardiovascular system must ensure that it is able to deliver a greater supply of nutrient rich blood to the active tissues, and ensure that the increasing levels of metabolic waste and by-products are removed.
the arteries supply the active tissues are signalled by the nervous system to relax. because arteries contain elastin, this relaxation causes blood pressure to exert a stretching effect which results in them widening or dilating = ‘vasodilation’.
the arteries supply non-active tissues are instructed by the nervous system to contract, reducing their diameter and causing them to constrict. this process reduces the blood that can pass through these arteries and diverts greater quantities of blood to the more active tissues that need it most = ‘vasoconstriction’
heart rate
also known as pulse
the number of times a person’s heart beats in a minute = BPM (beats per minute)
what constitutes a normal heart rate depends on a variety of factors, including age, body size, medical status, activity level, medication use, body temperature and even emotional state.
the two major sounds associated with the normal heart sound are ‘lub dub’.
the lub is the first heart sound, and is caused by the turbulence created by the closure of the bicuspid and tricuspid valves at the start of systole. the dub sound is caused by the closure of the aortic and pulmonic valves, marking the end of systole and the onset of diastole.
a typical resting HR for adults will range between 60-80 BPM depending on the interaction of the above variables. in children, the resting heart rate is normally a little higher, normally 70-90 BPM.
increased risk of myocardial ischemia
since the myocardium’s oxygen delivery occurs largely during diastole, excessive heart rates also create a ‘hypoxic’ (lack of oxygen) environment within the heart and significantly increase the risk of myocardial ischemia.
the 2 circulatory paths
1) the pulmonary circulation
2) the systemic circulation
pulmonary circulation
- blood travels from the heart, to the lungs and back
- it leaves the heart via the pulmonary artery, is oxygenated in the lungs, and returns to the heart via the pulmonary vein.
- the pulmonary system is therefore tasked with delivering blood to the lungs for oxygenation (and removal of carbon dioxide), and returning it back to the heart in preparation for its delivery around the body.
systemic circulation
concerned with the delivery of oxygenated blood from the heart to the body tissues and returning deoxygenated blood to the heart before it is delivered to the lungs of oxygenation. oxygenated blood leaves the heart via the aorta and is transported throughout the body in accordance with its needs. deoxygenated blood is then collected from the tissues and returned back to then heart via the inferior and superior vena cava before the cycle commences again.
functions of the heart
- pump deoxygenated blood from the heart and body tissues to the lungs for oxygenation
- to pump oxygenated blood from the heart and body tissues to be used as an energy source
those suffering from hypotension are more likely to develop other conditions and diseases including
- stroke
- transient ischemic attack (TIA - mini stroke)
- kidney failure
- retinopathy (can lead to blindness)
- heart failure
- peripheral artery disease
inappropriate exercises for hypotension
- isometric exercises
- overhead resistance exercises
- anaerobic interval training
- valsalva manoeuvre or any exercise where there is tendency to hold breath
primary risk factors of heart disease
- hereditary factors
- gender (men greater)
- age
- high blood pressure
- smoking
- high blood cholesterol
secondary risk factors of heart disease
- physical inactivity
- obesity and overweight
- diabetes
- alcohol
- stress
- hormone replacement therapy
cardiorespiratory adaptations to exercise (LUNGS)
- increased size of alveoli
- more efficient exchange of carbon dioxide
- increased capillarisation surrounding the alveoli
- increased strength of the respiratory muscles (diaphragm and intercostals)
- increased use of ‘dead space’ or residual volume resulting in a greater ventilatory capacity
cardiorespiratory adaptations to exercise (HEART)
- increased stroke volume
- increased cardiac output
- left ventricular hypertrophy
- reduced recovery heart rate
- capillarisation of the myocardium
- decreased resting and exercising heart rate resulting in a longer diastole
- increased end-diastole volume (amount of blood in the heart at the end of diastole)
atrioventricular valves (heart)
- ensure that blood only travels in one direction from atria to ventricles
- action is controlled by pressure; when ventricle wall contracts, the pressure within the ventricle increases, which forces atrioventricular valves to shut
- right atrioventricular valve = tricuspid valve
- left atrioventricular valve = bicuspid valve/ mitral valve
- less risk of back flow on left side because deoxygenated blood means higher pressure - why left valves have 2 cusps and right have 3 (bi and tri)
semi lunar valves (heart)
- located between ventricles and their arteries
- there are 2
- made up of 3 moon shaped crescents
- serve to regulate the passage of the blood from heart to arteries
- prevent back flow
- the one located between right ventricle and pulmonary artery is the pulmonary valve
- the one located between the left ventricle and aorta is the aortic valve
semi lunar valves and atrioventricular valves working together
when the myocardium surrounding the ventricles contracts, the increase in ventricular pressure simultaneously closes the atrioventricular valves and opens the semi-lunar valves to eject blood from the ventricles and into the vascular system
stenosis of the heart’s valves
some heart disease patients experience a stenosis of the heart valves which causes the to become permanently narrow and constricted.
this process may be triggered by scar tissue from existing heart condition, abnormal growths or calcium deposits
reduces hearts ability to deliver blood to the rest of the body and itself
common treatment is synthetic heart valve replacement
cardiac cycle (passage of blood through the heart)
- deoxygenated blood enters the right atrium via the superior and inferior vena cava
- simultaneously to this, oxygenated blood enters the left atrium via the pulmonary vein
- approx 70% of blood entering the heart passes straight into ventricles, but remaining 30% stays in atria until they contract
- during diastole, blood enters the atria and begins to fill the heart from the bottom up, the longer the diastole phase, the more the atria and ventricles will fill.
- when the myocardium surrounding the atria contracts, blood is forced from atria into ventricles through atrioventricular valves
- when pressure in ventricles exceeds atria, the atrioventricular valves close to prevent back flow
- rapid influx of blood into ventricles causes stretching of myocardium
- this results in Frank-Startling principle = rapid recoil during subsequent contraction of the myocardium and helps the heart in ejecting blood from the ventricles into the vascular system
- when ventricles contract their internal pressure increases, and when this pressure exceeds that in neighbouring arteries, the pulmonary and aortic valves are forced open and blood is ejected from ventricles into aorta and pulmonary arteries simultaneously
- the contraction of atria and ventricles occurs rapidly and is normally only separated by 0.02-0.06 seconds
- the contracting phase of the myocardium = systole - is the emptying and ejecting phase of the cardiac cycle
- the resting phases of the myocardium = diastole - filling phase, coronary arteries nourish the myocardium with oxygen; as such lower resting heart rates and higher stroke volumes, which both increase diastole are essential for healthy heart
blood pressure and exercise
- during exercise, there is normally a temporary increase in systolic blood pressure in order to achieve a higher rate of oxygen delivery to the active tissues
- during steady rhythmic exercise, systolic blood pressure rises rapidly during the first few minutes, until the initial oxygen debt has been repaid, and vasodilation of the blood vessels supplying the active muscles is sufficient to meet the oxygen demands of the activity.
- as the peripheral arteries dilate, systolic pressure normally stabilises
- it is not uncommon for the systolic pressure to rise to levels of 180mmHg during the initial stages of exercise ~ they normally stabilise at 140-160mmHg during moderate-vigorous intensity activities
- diastolic blood pressure generally remains unchanged during exercise and if it does it rarely exceeds 10mmHg
- in long term, regular exercise and physical activity normally result in a reduction of the resting systolic blood pressure
- but exercise alone will only induce modest reductions in systolic and diastolic pressure, as such dietary changes and/or medication may be required in some cases, especially when a disease is present
high risk total cholesterol and total cholesterol/HDL ratio
total cholesterol = less than 3.1 mmol/I, greater than 8.5 mmol/I
total cholesterol/HDL ratio = greater than 8:1
medium risk total cholesterol and total cholesterol/HDL ratio
total cholesterol = greater than 6.2 mmol/I
total cholesterol/HDL ratio = greater than 5:1
healthy total cholesterol and total cholesterol/HDL ratio
total cholesterol = 4.9-5.4 mmol/I
total cholesterol/HDL ratio = less than 3.5:1
free radicals
highly reactive and damaging to the bodily cells
formed during metabolism of oxygen
oxidised free radicals
when free radicals interact with LDL cholesterols
embed themselves into the wall of the artery = inflammation and scar tissue
smoking, excessive alcohol and diet high is trans fatty acids increases concentration of free radicals and this process
how to increase HDL cholesterol
regularly exercise, especially when combines with a diet low in saturated and trans fats
greater HDL relative to LDL levels, improves cardiovascular health and reduces risks of heart disease
the measure of blood cholesterol
concentration of blood cholesterol
mmol/I = millimoles per litre
recommended total cholesterol concentrations
total cholesterol = less than 5 mmol/I
total LDL cholesterol = less than 3 mmol/I
those with history of heart disease in their family should have these numbers at 4 and 2
benefit of working out total cholesterol/HDL level
HDLs have the ability to reduce the concentration of LDLs, so the ration between the two is more important than total cholesterol
