Week 2 cardiovascular disease Flashcards
What is cardiovascular disease?
A collective term describing the diseases affecting the heart and circulatory system.
What is a stroke caused by?
blocked or burst blood vessels in the brain
What is CHD?
Disease of the blood vessels to the heart , reducing blood supply to the heart muscle
What is myocardial infarction?
When blood supply to part of the heart is cut off
What is heart failure?
When the heart cannot pump properly and supply the body with enough oxygenated blood.
What is peripheral arterial disease?
disease of the arteries in the arms / legs
What is angina?
chest pains due to restricted blood supply to the heart muscle
What is rheumatic heart disease?
damage to the heart from rheumatic fever
What is congenital or birth heart defects?
defects of heart structures existing at birth, such as holes in the heart and abnormal valves
What is arrhythmia?
altered heart beat (faster or slower than normal)
What is deep vein thrombosis and pulmonary embolism?
blood clots formed in the leg veins which move to the heart and lungs.
In 2017, what was CVD responsible for in the UK?
28% of deaths (however, this has reduced significantly since 1969).
Why may death rate from CVD have reduced?
Better medical care
Improved treatment of CVD directly and also risk factors e.g. high cholesterol
Decline in smoking
What is the suggested relationship between exercise and CHD?
Dose response between vigorous exercise and risk of CHD.
Not the same association with non-vigorous exercise (non-apparent).
What did Arem et al (2015) find about leisure time PA and CVD mortality?
sedentary group at highest risk of mortality
Individuals accumulating some PA but not meeting the guidelines have 20% lower risk of CVD mortality
Individuals meeting PA guidelines have 33% lower risk
individuals accumulating 3-5x the guidelines only gain an initial 9% reduction in risk compared to those meeting guidelines and risk then increases slightly to higher than those meeting guidelines.
What did Barlow et al find about cardiorespiratory fitness and long-term survival in low risk adults?
A 1 MET increase in Vaseline cardiorespiratory fitness was associated with an 18% reduction in CVD deaths after adjustment for confounders.
What is atherosclerosis?
The build up of fatty materials which cause plaques on the arterial wall which over time can narrow the artery.
Though to be the main process which causes CVD).
Summarise the physiology of a normal artery
Inner layer is called the intima - has a single layer of endothelial cells in contact with the blood
Then have the tunica media which is a muscular layer - allows vasodilation/constriction
Outside layer is a structural layer made up of collagen - gives the vessel strength
What is general accepted as the first stage of atherosclerosis?
endothelial dysfunction (damage to endothelial cells)
This makes the endothelium permeable - movement of particles from blood into arterial wall
What is considered to be the first lesion of atherosclerosis?
LDL is particularly prone from moving from blood into endothelial wall
This causes a number of inflammatory responses - immune cells enter arterial wall where they differentiate into macrophages
These engulf LDL particles - forms foam cells
As foam cells accumulate they form a fatty streak
What can happen if the first lesion of atherosclerosis grows?
Smooth muscle cells from the tunica media proliferate and move into the intima
They start to accumulate along with other substances such as collagen - start to develop a core of lipids and debris enclosed in a cap.
This will start to protrude into the blood vessel - narrowing the artery - susceptible to rupture.
Its at this point that blood clots can start forming and may see some cardiovascular consequences.
What is one of the prime mechanisms by which PA will reduce CVD?
Due to its effects on lipids / lipoproteins
What is chylomicron?
responsible for transporting dietary triglycerides in the body - transports fats we eat from small intestine to sites around the body (high levels increase risk of CVD).
What is VLDC?
transports endogenous triglycerides. These are triglycerides that are synthesised within the body at the liver. Transported around body to key sites such as muscle and adipose tissue. (high levels increase risk of CVD).
What is LDL?
The primary transporter of cholesterol (high levels increase risk of CVD).
What is HDL?
This is protective. Removes cholesterol from the system (reverse cholesterol transport).
What does research suggest about exercise and lipid / lipoprotein levels?
LaPorte (1983) compared HDL in runners and people with spinal chord injuries, results suggest high HDL levels may be associated with higher levels of PA.
Also suggestions that exercise training reduces levels of VLDL and LDL (Slentz et al, 2007). Although 15 days after last training session there is a reduction in magnitude so suggests regularly need to exercise to maintain the benefits.
A study by Kokkinos et al. (1996) looked at a study of African Americans with a high prevalence of hypertension. What did the results suggest about PA and blood pressure?
Exercise caused a significant decrease in DBP evident at 16 and 32 weeks (with substantial reductions in medication).
Also caused a significant decrease in interventricular septum thickness and left ventricular mass at 16 weeks.
Why might exercise cause benefits to blood pressure - acute?
increased endothelial-dependant vasodilation (e.g. histamine)
arterial baroflex resetting (decreased sympathetic nerve activity and norepinephrine)
Why might exercise cause benefits to blood pressure - chronic?
likely that some of the benefits are adaptations that occur because of regular application of acute pathways
arterial remodelling
decreased inflammation and adiposity
increased insulin sensitivity
these factors increase cross sectional area of lumen and decrease vessel wall thickness
How does increased cross sectional area of lumen reduce blood pressure?
leads to reduced resistance to blood flow
Define endothelial function?
The ability of the endothelium to interact with vascular smooth muscle to influence blood flow.
What is one of the main ways in which endothelial function works?
Through the release of a vasodilator called nitric oxide. This diffuse into the muscles causing them to relax (causes vasodilatory effect in the blood vessel).
How does exercise affect endothelial function?
increased endothelial shear stress leads to
increased endothelial nitric oxide synthase (eNos) lead to
increased nitric oxide availability (vasodilation) leads to
improved endothelial function.
why are associations for fitness stronger than those for just PA?
issues with recall bias with PA
fitness is quantitative
fitness has strong genetic component
what was the results of the STRRIDE study?
Found exercise training created reductions in VLDL triglyceride and increased HDL
What is poste exercise hypotension?
Reduction in BP following acute exercise
how long does post exercise hypotension last?
24hrs
what is norepinephrine?
vasoconstrictor
why are we interested in endothelial function?
Endothelial dysfunction is involved at several stages of atherosclerosis
Endothelium has receptors that attract immune cells involved in early inflammatory responses
Important role in our adaptations to exercise
primary adaptation of endothelium function with exercise
improving vasodilatory response
what is ACTH?
neurotransmitter that usually initiates vasodilatory response in blood vessels
with ACTH what happens?
vasoconstriction
this is an abnormal responses - the patients have CHD
In the early period of training what do we see and then what happens?
The functional adaptation occurs before the structural adaptations
The functional response with nitric oxide due to sheer stress drives the structural adaptation, once structural adaptation occurs in later training periods this takes place of any functional changes
