Cardiovascular disease risk is shaped by both inherited characteristics and lifestyle choices. These factors often interact, changing how likely a person is to develop damage to the heart or blood vessels.

Understanding cardiovascular risk

Cardiovascular disease (CVD) covers conditions affecting the heart and blood vessels, including coronary heart disease and stroke. A risk factor is any feature that increases the chance of developing disease, but it does not mean disease is certain.

Risk increases when factors damage artery walls, encourage fatty deposits to form, or make the heart work harder over long periods.

This diagram shows how atherosclerosis develops from an initially intact endothelium to an injured artery where immune cells enter the vessel wall and form foam cells, eventually producing a plaque (atheroma). The growing plaque thickens the arterial wall and narrows the lumen, reducing blood flow and increasing the risk of blockage. Source

Biological risk factors

Genetics

Some people inherit gene variants that increase CVD risk. These may affect:

• blood cholesterol levels

• blood pressure regulation

• the tendency of blood to clot

• how easily artery walls become damaged

This means a person may be more likely to develop cardiovascular disease even if they do not show symptoms when young. A family history of CVD can therefore suggest increased risk. However, family members often share diets and habits as well as genes, so genetics increases susceptibility rather than guaranteeing disease.

Age

CVD risk usually rises with age. This is partly because artery walls experience wear and tear over many years. Older people have also had longer exposure to other risks such as poor diet, smoking, or high blood pressure.

As people age:

• arteries may become less elastic

• damage to the endothelium can accumulate

• the chances of developing raised blood pressure increase

The longer these changes continue, the greater the chance of serious cardiovascular problems.

Gender

In this topic, gender is usually discussed as biological sex differences. Men often have a higher risk of CVD earlier in life than women. Before menopause, women may have some protection because estrogen tends to support a more favorable blood lipid profile and may help maintain blood vessel health.

After menopause, this protective effect falls, so CVD risk in women increases. This does not mean all men are high risk or all women are low risk; it means sex is one factor that influences overall probability.

Lifestyle risk factors

Diet

A poor diet can increase CVD risk in several ways:

• Diets high in saturated fat can raise LDL cholesterol, increasing the chance of fatty deposits in arteries.

• Too much salt can raise blood pressure.

• Frequent intake of energy-dense foods can promote weight gain, which is often linked with poorer cardiovascular health.

• Low intake of fruit, vegetables, and fiber may reduce protective effects in the diet.

Long-term diet patterns matter more than a single meal. The main effect is that poor diet can gradually create conditions that damage blood vessels and increase strain on the heart.

Smoking

Smoking is a major modifiable risk factor. Chemicals in tobacco smoke damage the endothelium, the thin lining of blood vessels. This makes it easier for fatty deposits to build up.

Smoking also increases risk because:

This graph compares normal oxygen–hemoglobin behavior with blood containing high carboxyhemoglobin (COHb), showing a marked reduction in oxygen content for a given $P\mathrm{O_2}$. It helps explain why carbon monoxide exposure from smoking lowers the blood’s oxygen-carrying capacity, forcing the cardiovascular system to compensate by increasing workload. Source

• nicotine raises heart rate and can raise blood pressure

• carbon monoxide binds to hemoglobin, reducing oxygen transport

• the heart may need to work harder to meet the body’s oxygen demands

• blood becomes more likely to clot

These effects make blockage of blood vessels more likely and increase the chance of heart attack or stroke.

Inactivity

A lack of regular exercise, or inactivity, increases CVD risk. Physically active people usually have better cardiovascular fitness and healthier blood vessels. By contrast, inactivity is associated with:

• poorer control of body mass

• higher blood pressure

• less favorable blood lipid levels

• reduced efficiency of the heart and circulation

An inactive lifestyle therefore increases long-term strain on the cardiovascular system, especially when combined with other risk factors such as poor diet.

High blood pressure

High blood pressure is a risk factor in its own right and may also result from other factors such as age, diet, inactivity, and inherited tendency.

When blood pressure stays high, blood pushes against artery walls with greater force. This can damage the endothelium and make fatty deposits more likely to form. The heart must also generate more force to pump blood, which increases its workload.

Over time, hypertension can:

• increase damage to arteries

• make the heart work less efficiently

• raise the chance of cardiovascular disease developing

How risk factors interact

Risk factors rarely act alone. A person who smokes, eats a poor diet, and is physically inactive may also develop high blood pressure, so their overall risk becomes much greater than from one factor by itself.

It is useful to divide risk factors into two groups:

• non-modifiable factors: genetics, age, and gender

• modifiable factors: diet, smoking, inactivity, and some causes of high blood pressure

Even though non-modifiable factors cannot be changed, they help identify people who may need earlier monitoring or stronger lifestyle management. Modifiable factors are important because changing them can reduce overall cardiovascular risk. Assessing risk therefore requires these factors to be considered together rather than one at a time.