Question at position 1 Physical activity reduces the relative risk of developing cardiovascular disease by:lowering HDL cholesteroldecreasing the size of coronary arteriesincreasing blood pressureimproving endothelial functionClear my selection单项选择题
A
lowering HDL cholesterol
B
decreasing the size of coronary arteries
C
increasing blood pressure
D
improving endothelial function

Question

Question at position 1 Physical activity reduces the relative risk of developing cardiovascular disease by:lowering HDL cholesteroldecreasing the size of coronary arteriesincreasing blood pressureimproving endothelial functionClear my selection单项选择题

A

lowering HDL cholesterol

B

decreasing the size of coronary arteries

C

increasing blood pressure

D

improving endothelial function

BlackTom AI · Accepted Answer

Improving endothelial function is the principal mechanism by which regular physical activity reduces cardiovascular disease (CVD) risk.

1. Relevant knowledge points and concepts
- Endothelium: inner lining of blood vessels that regulates vascular tone, coagulation, inflammation, and vessel growth. Healthy endothelium produces nitric oxide (NO), causing vasodilation and inhibiting platelet aggregation and smooth muscle proliferation.
- Exercise effects: regular aerobic activity increases shear stress on vessel walls, upregulates endothelial NO synthase (eNOS), reduces oxidative stress and inflammation, improves insulin sensitivity, and favorably alters lipid profiles and blood pressure.
- Incorrect concepts in distractors: HDL cholesterol typically increases (not decreases) with exercise; coronary artery size is not reduced by beneficial exercise-induced adaptations; resting blood pressure usually decreases with regular aerobic training.

2. Step-by-step reasoning
Step 1: Identify mechanism most directly linked to reduced CVD risk. Endothelial dysfunction is an early and central event in atherosclerosis and thrombosis; improving it reduces plaque formation and thrombotic events.
Step 2: Evaluate each option against known exercise physiology:
- "Lowering HDL cholesterol": exercise tends to raise or maintain HDL, which is protective, so lowering HDL would raise risk, not reduce it.
- "Decreasing the size of coronary arteries": reduction in arterial lumen would impair flow and worsen ischemia; exercise causes favorable remodeling (improved vasodilation and sometimes increased lumen), not shrinking.
- "Increasing blood pressure": chronic exercise lowers resting blood pressure in hypertensive and normotensive individuals; increasing BP would elevate CVD risk.
- "Improving endothelial function": matches established mechanisms (increased NO, reduced inflammation, less thrombosis), thus directly lowering CVD risk.

3. Intermediate steps/calculations
No numerical calculation is required. Mechanistic chain: exercise → increased shear stress → ↑ eNOS/NO, ↓ oxidative stress & inflammation → improved endothelial function → reduced atherosclerotic progression and thrombosis → lower relative risk of CVD.

4. Why the correct answer is correct
Improved endothelial function addresses the root pathophysiology of atherosclerosis and thrombosis by restoring vasodilation, reducing leukocyte adhesion and platelet aggregation, and limiting smooth muscle proliferation—leading to measurable reductions in cardiovascular events.

5. Why other options are incorrect (brief)
- Lowering HDL cholesterol: opposite of exercise effect; would increase risk.
- Decreasing coronary artery size: would worsen perfusion; not a beneficial adaptation.
- Increasing blood pressure: contradicts evidence that exercise lowers resting BP and reduces CVD risk.

Conclusion: The correct answer is improving endothelial function, which matches the provided answer.

Question at position 1 Physical activity reduces the relative risk of developing cardiovascular disease by:lowering HDL cholesteroldecreasing the size of coronary arteriesincreasing blood pressureimproving endothelial functionClear my selection单项选择题

类似问题

What happens to the resting heart rate as a result of regular endurance exercise?

Noradrenaline (NA, 10 μg/kg) is injected into an anaesthetised rat and effects on arterial blood pressure (ABP, top panel) and heart rate (HR, bottom panel) are shown below. Which of the following antagonists would MOST LIKELY prevent the effect on HR?

For each of the following, predict the overall effect that injection of this drug would have on total peripheral resistance (TPR) in an anaesthetised rat. 1: angiotensin II 2: acetylcholine 3: noradrenaline 4: isoprenaline

If a person has a blood pressure of 130/90, which of the following would be true?

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Question at position 1 Physical activity reduces the relative risk of developing cardiovascular disease by:lowering HDL cholesteroldecreasing the size of coronary arteriesincreasing blood pressureimproving endothelial functionClear my selection单项选择题

类似问题

What happens to the resting heart rate as a result of regular endurance exercise?

Noradrenaline (NA, 10 μg/kg) is injected into an anaesthetised rat and effects on arterial blood pressure (ABP, top panel) and heart rate (HR, bottom panel) are shown below. Which of the following antagonists would MOST LIKELY prevent the effect on HR?

For each of the following, predict the overall effect that injection of this drug would have on total peripheral resistance (TPR) in an anaesthetised rat. 1: angiotensin II ____ 2: acetylcholine ____ 3: noradrenaline ____ 4: isoprenaline ____

If a person has a blood pressure of 130/90, which of the following would be true?

Which one of the following would be true during chronic systemic high blood pressure (hypertension)?

Consider Ohm's law where CO (Flow) = MAP/TPR: If total peripheral resistance suddenly doubled, then the systemic blood pressure must ________ in order to maintain the same CO (same amount of blood flow).

The most significant increase in blood pressure, assuming blood flow (cardiac output) remains constant, can be produced by [ Select ] increasing decreasing total peripheral resistance (TPR), particularly when this is achieved by [ Select ] decreasing increasing arteriolar radius.

更多留学生实用工具

希望你的学习变得更简单

For each of the following, predict the overall effect that injection of this drug would have on total peripheral resistance (TPR) in an anaesthetised rat. 1: angiotensin II 2: acetylcholine 3: noradrenaline 4: isoprenaline