Explain how smoking cigarettes increases the risk of cardiovascular disease.

Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 1.1 Cardiovascular disease and risk · Explain · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Cardiovascular disease (CVD) is one of the leading causes of death in the UK. Lifestyle factors, including smoking, are known to increase the risk of developing CVD.

Model answer (5 marks)

Carbon monoxide in cigarette smoke binds to haemoglobin, reducing the blood’s oxygen‑carrying capacity. The heart therefore has to beat faster and work harder to supply tissues with oxygen. Nicotine stimulates the sympathetic nervous system, raising heart rate and blood pressure. The resulting hypertension damages the endothelial lining of arteries, promoting the formation of fatty deposits (plaques). These plaques narrow the arterial lumen, restricting blood flow to the heart and increasing the likelihood of a heart attack.

Examiner tips

Use the exact terms: carbon monoxide, haemoglobin, oxygen‑carrying capacity, heart rate, blood pressure, hypertension, endothelial lining, fatty deposits, plaques, lumen, heart attack.
Show the causal chain: CO → ↓O₂ → ↑HR/effort → nicotine → ↑HR/pressure → damage → plaque → narrowed lumen → heart attack.
Keep answer concise – 5 points, no extra wording.

Common mistakes

Mixing up carbon monoxide with nicotine as the main cause of reduced oxygen delivery.
Failing to mention the damage to the arterial lining or the formation of plaques.
Using vague terms like ‘bad habits’ instead of specific physiological effects.

Mark scheme (5 marks)

Carbon monoxide from cigarette smoke binds to haemoglobin (reducing oxygen-carrying capacity of the blood)
The heart must beat faster / work harder to compensate for reduced oxygen delivery to tissues
Nicotine in cigarette smoke causes an increase in heart rate / blood pressure
High blood pressure damages the inner lining / walls of arteries
Fatty deposits / plaques build up in artery walls, narrowing the lumen and restricting blood flow to the heart, increasing the risk of a heart attack

Key terms in this question

cardiovascular disease