The coronary arteries deliver blood to the heart muscle itself. They can narrow over decades through atherosclerosis — a gradual build-up of fatty deposits in the artery wall. If a deposit ruptures and a clot forms, blood flow can stop altogether. That is a heart attack, known medically as a myocardial infarction.

Heart failure sounds more alarming than it often is. It means the heart is not keeping up with what the body is asking of it. Sometimes the main pumping chamber has become weak; sometimes pumping strength is preserved but the heart has become stiff and pressure backs up. Both cause breathlessness, fatigue and swelling, and both are treatable.

The heart has four valves that keep blood moving in one direction. A valve can become narrowed, so blood struggles through, or leaky, so blood flows backwards. Either way the heart works harder. Valve problems are often first picked up as a murmur, and the usual test is an echocardiogram — a specialised ultrasound of the heart.

No. The same process affects the arteries to the brain, the kidneys and the legs, which is why it also causes stroke, kidney disease and poor circulation in the limbs. Treating cardiovascular risk protects more than just your heart.