Coronary Heart Disease

What coronary heart disease actually is

The coronary arteriessupply the heart muscle with blood. In coronary heart disease, these arteries become narrowed or blocked, which reduces blood flow to the part of the heart muscle they supply. Less blood reaching that muscle means less oxygen delivered to it, which lowers its capacity for aerobic respiration — and if the blockage is severe enough, the affected heart tissue can be damaged and the heart’s ability to function normally can be impaired. Cambridge does not require detailed pathology beyond this, but it is worth holding onto that chain — narrowed artery → less blood → less oxygen → impaired muscle function — because it is what turns “a blocked vessel” into a biologically meaningful answer rather than a vague statement of harm.

The seven risk factors

Cambridge specifies seven possible risk factors, and it is worth knowing all seven precisely rather than recalling a partial list under exam pressure: diet, lack of exercise, stress, smoking, genetic predisposition, age and sex. A risk factor changes the probabilityof developing coronary heart disease — it does not guarantee that the disease will occur, and having none of the seven does not reduce a person’s risk to zero.

It helps to notice that these seven split naturally into two groups. Diet, exercise habits and smoking can all be changed by a person’s own behaviour. Age, sex and genetic predisposition cannot be changed at all. Stress sits somewhere in between, since it can sometimes be managed but isn’t simply a lifestyle choice in the way diet or smoking are. That distinction matters for the next section, because Cambridge specifically asks candidates to discuss diet and exercise — the two modifiable factors it focuses its reduction question on.

Reducing risk through diet and exercise

Cambridge’s command here is to discussthe roles of diet and exercise, which means an answer needs to do more than simply list them — it needs to state the mechanism connecting each one to risk. A diet that avoids excessive intake of the foods associated with coronary heart disease, and that supports a healthy body mass, contributes to lower risk over time; the point is not that any single food “causes” or “cures” the disease, but that dietary pattern shifts probability. Regular physical activity supports cardiovascular fitness and helps maintain a healthy body mass, and through those effects it is associated with reduced risk.

Neither diet nor exercise can reduce risk to zero, because the other five factors — including age, sex and genetic predisposition, none of which are within a person’s control — still contribute. A complete discussion says risk is reduced, not eliminated, and links each behaviour to why it lowers risk rather than stopping at “exercise is good for the heart.”

Don’t confuse

Coronary heart disease affects blood flow to the heart muscle itself, through the coronary arteries — it is not the same statement as “the heart stops.” And a risk factor being present is not proof that disease will follow; it changes the odds, nothing more. For the structures involved, see the coronary arteries on the mammalian heart page, and for how vessel structure relates to the pressure blood is carried at, see arteries, veins and capillaries.