What the heart does
Cardiovascular disease (heart and circulatory diseases) is the biggest killer in the UK, so it is important to understand what the heart does and what to do if you think you are at risk. By Dr Chris Browne.
Each day, your heart beats about 100,000 times and pumps about 23,000 litres (5,000 gallons) of blood. Well, it's the same five litres of blood constantly refreshed with oxygen and nutrients which the heart pushes to all parts of your body, and carries away unwanted carbon dioxide and waste products.
The heart and circulatory system
Blood is pushed through the heart by the heart muscle contracting. With each contraction, or heartbeat, the heart pumps blood forward from the left side of the heart through the aorta and into the arteries.
The arteries divide into smaller and smaller branches to supply capillaries, taking the blood to every part of your body. The blood then travels back from the capillaries into the veins to the right side of your heart.
As the heart relaxes between each contraction, blood from the lungs fills the left side of your heart. The two sides of the heart are separate, but they work together.
The right side of the heart receives dark, de-oxygenated blood which has circulated around your body. It pumps this to your lungs, where it picks up a fresh supply of oxygen and becomes bright red again.
Circulation is the continuous movement of blood around the body, pumped by the heart. This system is called the cardiovascular system.
What is cardiovascular disease?
Cardiovascular disease is also known as heart and circulatory disease, and this term covers all diseases that affect the heart and circulatory system.
It's the most common cause of death in the UK and includes coronary heart disease, angina, heart attack and stroke.
Coronary heart disease is caused by a gradual build up of fatty deposits on the walls of your coronary arteries.
This causes the artery to narrow, and makes it harder for the artery to supply your heart muscle with blood and oxygen.
The medical term for this condition is atherosclerosis.
Over time, the artery may become so narrow that it can't deliver enough blood oxygen to your heart, especially when you're exerting yourself. This can lead to angina - a pain or discomfort in your chest.
A heart attack occurs when a piece of the fatty deposits breaks away from the artery wall and causes a blood clot to form. If this clot then blocks the artery, your heart muscle will be starved of blood and oxygen.
A heart attack is a medical emergency and if you suspect that you or someone else is having one, you must call 999 immediately.
What to do if you think you are at risk
As you get older, your risk of cardiovascular disease increases. If you're worried that you might be at risk, your GP or practice nurse can carry out a risk assessment. Risk factors include:
- High blood pressure;
- High blood cholesterol;
- Physical inactivity;
- Being overweight or obese;
- A family history of heart disease;
- Ethnic group - some ethnic groups have a higher risk of heart disease. South Asian people living here have a higher risk that the rest of the population.
Your GP or practice nurse will ask assess your risk by:
- Asking questions about your lifestyle;
- Taking your weight, height and waist measurements;
- Taking your blood pressure;
- Having your blood tested for cholesterol;
- Asking questions about your family history.
After your assessment, your GP or practice nurse may give advice to help you make changes to your lifestyle to reduce your risk of heart disease.