L1: Cardiovascular Disease

Question 1

What percentage of UK deaths is attributable to CVD in 2018?

Answer 1

27%

Question 2

What where the two experiments to identify the association between physical activity and CHD?

Answer 2

Morris et al, 1980: London bus conductors

Paffenbarger 1975: Work intensity

Question 3

What curve does volume of physical activity follow as a risk factor for CVD mortality?

Answer 3

U-shaped curve

Question 4

What range of physical activity (Met hours per week) is associated with the lowest risk of CVD mortality and what is the risk reduction?

Answer 4

15 - 40 MET hours per week reduces the risk of mortality from CVD by 42% compared to sedentary people

Question 5

Other than physical activity, what other modifiable risk factor for CVD mortality is there>

Answer 5

Cardiorespiratory fitness

Question 6

Who identified the association between cardiorespiratory fitness and CVD mortality?

Answer 6

Barlow et al

Question 7

What reduction in risk is associated with a 1 MET increase in cardiorespiratory fitness?

Answer 7

18% CVD mortality reduction

Question 8

What did Tikkenan et al, 2018 identify?

Answer 8

• Cardiorespiratory fitness is capable of reducing the risk caused by high genetic risk.
• Those with high cardiorespiratory fitness reduced there risk below 1 despite having high genetic risk.

Question 9

What are the three layers of arteries?

Answer 9

Tunica intima, Tunica media and tunica externa

Question 10

What is the tunica intima?

Answer 10

Inner muscular layer which contains a layer of endothelial cells

Question 11

What is the Tunica Media?

Answer 11

Smooth muscular layer responsible for vasoconstriction and vasodilation

Question 12

What is the Tunica Externa

Answer 12

Connective tissue composed of mainly collagen and elastin responsible for providing structure and support.

Question 13

Describe the process of Atherosclerosis formation

Answer 13

1) Damage to the endothelial lining of blood vessels leads to increased permeability between the blood and vessel wall.
2) Increased diffusion of LDLs and VLDLs into the tunica media.
3) Immune response recruits circulating monocytes which differentiate into macrophages.
4) Macrophages engulf lipid molecules becoming foam cells which contribute to the formation of fatty streaks
5) Smooth muscle cells migrate and proliferate and collagen deposition occurs ultimately producing an advance fibrous cap lesion.
6) The AFC causes a thrombus that can either rupture causing an haemorrhage or break off causing a clot. This can lead to a myocardial infarction or stroke.

Question 14

What causes damage to the endothelial lining?

Answer 14

1) High blood pressure
2) Diabetes
3) High cholesterol
4) Smoking
5) Chronic low grade inflammation

Question 15

What is the clinical identification of CVD?

Answer 15

40% reduction in blood flow identifies as cardiovascular disease

Question 16

When does atherosclerosis begin developing and how does this effect primary intervention?

Answer 16

Development has been identified in very early ages and so primary intervention needs to occur early in life.

Question 17

What are other risk factors for Cardiovascular Disease?

Answer 17

1. Physical inactivity/activity
2. Lipid metabolism
3. Blood pressure
4. Vascular function
5. Inflammation

Question 18

How is physical inactivity a modifiable risk factor?

Answer 18

1. Physical inactivity reduces GLUT-4 recruitment in muscle cells. GLUT-4 receptors are responsible for Glucose uptake, meaning the more insulin is required for a given glucose uptake.
2. Physical inactivity leads to elevated blood pressure which increase arterial stress and contributes to endothelial damage.

Question 19

What are chylomicrons?

Answer 19

Transport molecules responsible for the transport of dietary triglycerides from the small intestines to peripheral adipose.

Question 20

What do VLDL do?

Answer 20

Transport of endogenous triglycerides from the liver to peripheral adipocytes

Question 21

What do LDL do?

Answer 21

Transport of cholesterol around the body

Question 22

What does HDL do?

Answer 22

Transport and removal of cholesterol from circulation

Question 23

What to lipid transport molecules can provide protective benefits against cardiovascular disease?

Answer 23

VLDL reduces in response to exercise which prevents the over accumulation of adipocytes and the development of chronic inflammation.

HDL increases in response to exercise which increases the removal of cholesterol from the circulating blood, reducing the effect of cholesterol of endothelial dysfunction and damage.

Question 24

How can acute and chronic exercise modify blood pressure and subsequently cardiovascular disease risk?

Answer 24

Acute
transient Reduction in systolic blood pressure hours after exercise caused by increased endothelial-dependent vasodilation. Vasodilation occurs in response to increased vascular resistance from exercise.

Arterial baroreflex resetting occurs which reduces parasympathetic nerve activity meaning reduced epinephrine responsible for vasoconstriction. Subsequently, vasodilation increases.

Chronic
chronic exercise promotes IL-10 anti-inflammatory cytokine release whilst decreasing IL-6 and TNF-Alpha thus changing the inflammatory profile of the body.

Angiogenesis occurs along with increase lumen size of blood vessels resulting in increased cross-sectional area. Wall thickness is also reduced and overall blood pressure is lower.

Question 25

Who’s study identified increased HDL from exercise and what year?

Answer 25

LaPorte et al, 1983

Question 26

What is the STRRIDE study ?

Slentz et al, 2007

Answer 26

Randomised control study on the effects exercise has on cholesterol composition.
Showed that High intensity exercise increases HDL and decreases LDL.
HDL increase is effected by both exercise duration and intensity.
This effect occurs 15 days after training session

Question 27

What sort of exercise and duration is needed to induce a reduction in blood pressure? Also how long does the effects last

Answer 27

low-intensity exercise such as standing and walking is enough to reduce arterial blood pressure, this is irrespective of intermittent or continuous exercise, with both causing the same effect.

This effect can last up to 24 hours, know as post-exercise hypotension.

Question 28

What is endothelial dysfunction?

Answer 28

The inability to interact with vascular smooth muscle to influence blood flow.

Question 29

What are the key processes of endothelial dysfunction?

Answer 29

• decreased monocyte uptake reduces the ability to remove lipids via macrophages.
• Reduced release of histamines and nitric oxide for endothelial-dependent vasodilation.

Question 30

What is the physiological process in which exercise induces endothelial-dependent vasodilation?

Answer 30

1) Exercise increases blood flow
2) Increased blood flow increases interaction between blood and endothelial (shear stress)
3) Increased nitric oxide synthase activity from endothelium responsible for catalysing nitric oxide
4) elevated nitric oxide release promotes vasodilation
5) Increase endothelial function

Question 31

What is the gold standard of measuring endothelial function?

Answer 31

Infusion of acetylcholine and measuring how much vasoconstriction occurs

Question 32

What is a non-invasive technique to measure endothelial function and how does it work?

Answer 32

Flow-mediated dilation
Ultrasound measures blood Flow and occlusion bands are used to restrict blood flow for a standardised period of time.
Measure the vasodilatory response to when occlusion bands are released.

Question 33

How does exercise effect endothelial function of vasodilation?

Answer 33

Initial 2 weeks of exercise increases nitric oxide production via endothelial stress caused by increased blood flow.
After 2 weeks endothelial function seems to decrease but in reality this is caused by angiogenesis which increases blood vessel diameter which ultimately reduces blood pressure.