How your heart works

Your heart sits in your lower chest, on the middle-left. It’s about the size of a clenched fist.

The heart’s job is to pump blood round your body, delivering the oxygen and nutrients your body needs to be healthy and work properly. 

Heart structure

A normal heart has 2 sides - left and right, separated by a muscular wall. Each side has 2 chambers:

  • Atrium: a smaller upper chamber
  • Ventricle: a larger lower chamber that pumps. 

Valves control the direction the blood flows between atrium and ventricle. 

The left side of your heart pumps blood out around your body to deliver oxygen and nutrients. 

When the blood comes back to your heart after travelling round your body, it’s low in oxygen. Your heart’s right side collects the returning blood, and pumps it to your lungs to collect oxygen. The oxygen-rich blood is then sent to the left side to start the process again. 

The left ventricle is bigger than the right, because it has to pump blood further round the body.

Electrical system

The heart’s pumping is controlled by special fibres that send electrical signals to the chambers.

How your heart works

Circulatory system

Blood is pumped around your body through a network of blood vessels. Your heart and these blood vessels make up your circulatory system.

  • Arteries carry the oxygen-rich blood from your heart to deliver it to your body. Coronary arteries are special arteries that supply the heart as a muscle with blood to keep it working well. 
  • Capillaries are tiny blood vessels that connect arteries and veins. Capillaries carry blood to the body cells where oxygen and nutrients are delivered, and waste is taken away.
  • Veins carry the blood from your body back to your heart after the oxygen and nutrients are delivered. By now the blood is low in oxygen and needs to pass through the lungs again and receive more oxygen.

Heartbeat and pulse

At rest, your heart beats at a rate of about 60 to 100 times a minute (a child's heart rate is higher). In an average lifetime, a heart will beat around 3 billion times.

When you are physically active, excited or ill, your heart rate can rise significantly. This is a natural response.

There are two parts to each heartbeat:

  • the systole is when the heart contracts and pumps blood
  • the diastole is when the heart relaxes, after contraction, so the chambers can refill with blood.

Every heartbeat results in blood moving forward through your arteries. You can feel this movement as a 'pulse' by placing two fingers over the artery of your wrist. Your pulse rate tells you how fast your heart is beating. 

When things go wrong with your heart

Some heart problems happen from birth (known as congenital). Others develop over time because of lifestyle and other factors, especially ageing. Some heart problems can be hereditary (passed on through families).

Over time, people can develop conditions like high blood pressure and high cholesterol. These, along with other risk factors, increase your risk of coronary heart disease. Coronary heart disease causes symptoms like angina, and can lead to a heart attack or stroke. 

Some heart problems, like arrhythmias and atrial fibrillation happen when the heart beat (rhythm) is abnormal.

Sometimes the heart or its valves can become inflamed, damaged or weak. Examples of these types of problems are cardiomyopathy, rheumatic heart disease, and in severe cases, chronic heart failure

Looking after your heart

The best way to look after your heart and prevent heart disease is having a heart-healthy lifestyle.

Share this

Booklet

Your heart (PDF)

How it works - all you need to know

View online More publications

Time for another #SaltShocker! Which has the most salt? @VicHealth donttrustyourtastebuds.com.au