Your heart is the size of your fist and the strongest muscle in your body.

Your heart started beating about three weeks after you were conceived. If you live to be 70 your heart will have beat two and a half billion times. Each heartbeat pumps blood around the body, pushing it from the left heart chambers, through arteries of ever-decreasing size, finally reaching the capillaries in all parts of the body.

Once your body has taken oxygen and nutrients from the blood, it is returned to the heart via the veins to the right chambers of the heart. On its way back, the blood passes through the liver and waste products are removed.

As marvelous as this system is, it is very vulnerable to damage from the things we do to it, like smoking, eating an unhealthy diet or putting it under stress. Or you may be born with a heart condition. When your heart’s functions become compromised, this is known as cardiovascular disease, a broad term that covers any disorder to the system that has the heart at its centre.