Narrowed and hardened arteries
Many circulatory diseases begin with atherosclerosis, the build-up of fatty deposits (plaque) rich in cholesterol on the inner walls of arteries. The artery becomes narrow and stiff, so less blood flows through. If a plaque or clot blocks a coronary artery supplying the heart muscle, part of the muscle dies — a heart attack (myocardial infarction). If the blockage or a burst vessel affects the brain, it causes a stroke.
Blood pressure problems
Hypertension (persistently high blood pressure) forces the heart to work harder and damages vessel walls, raising the risk of heart attack, stroke and kidney disease. It often has no symptoms, which is why it is called a "silent" condition and should be checked regularly.
Example
A middle-aged man who smokes, eats fried food daily and rarely exercises has narrowed coronary arteries. During exertion his heart muscle cannot get enough oxygen, causing chest pain (angina) — a warning sign of coronary heart disease.
Blood disorders and prevention
Anaemia is a shortage of healthy red blood cells or haemoglobin, often due to lack of iron, leaving the body short of oxygen and causing tiredness and pale skin. Leukaemia is a cancer in which abnormal white blood cells multiply uncontrollably. Many circulatory diseases share the same risk factors — smoking, a diet high in saturated fat and salt, obesity and physical inactivity. Because these diseases often build up silently over many years, regular health screening — checking blood pressure, cholesterol and blood sugar — allows problems to be caught and treated early, before a heart attack or stroke occurs.
Key idea
A heart-healthy lifestyle — no smoking, less saturated fat and salt, more fruit, vegetables and exercise, and a healthy body weight — lowers the risk of atherosclerosis, hypertension, heart attack and stroke.