How does the heart work?

Find out how exactly the heart functions, issues that can affect it and how to keep the heart healthy

S.A.C. Dip (Diet, Exercise & Fitness), Advanced Human Anatomy & Physiology Level 3
Ask Louise

28 February 2020

How does the heart work?

The heart pumps oxygenated blood and nutrients around the body to tissues and organs through blood vessels known as arteries.

Once these have been delivered, deoxygenated blood and waste is returned to the lungs and heart through blood vessels called veins.

Outlined below are a few key terms related to heart health.

Arteries – these carry oxygen-rich blood away from the heart towards various organs. The aorta is the artery through which blood leaves the heart to reach other areas of the body and deliver oxygen and nutrients. The pulmonary artery carries blood from the heart to the lungs so that it can be oxygenated, and sent around the body.

Blood – this part of the circulatory system transports nutrients and other substances around the body. It feeds the cells and has to be kept moving as cells need to be fed constantly in order to stay alive and functioning.

Capillaries – these tiny vessels connect arteries and veins, as well as carrying vital oxygen to tissues, and removing carbon dioxide from them.

Cardiovascular system – central to this system is the heart. It functions as a pump, moving blood forwards in the blood vessels (known as the peripheral circulation).

Circulatory system – this consists of the heart, arteries, veins, capillaries, blood and lymphatic system. It is a transport mechanism used to supply cells with nutrients and oxygen and, in turn, removes carbon dioxide and other waste material from the cells to be excreted. It is instrumental in distributing hormones and other chemicals involved in normal cell function and also helps to regulate body temperature.

Coronary – this refers to the arteries which surround the heart and supply it with blood.

Heart valves – these ensure blood keeps flowing in one direction though the chambers of the heart. These also stop blood flowing backwards into the heart once it has been pumped out.

Veins – another means for blood to travel throughout the body, veins carry blood back to the heart, most of which is deoxygenated.

How does the heart work?

The heart is a muscle made up of tissue that sits roughly in the centre of the chest. It has four chambers: the smaller left and right atriums, and the larger left and right ventricles.

The sinus node, which is positioned in the right atrium, keeps the heart pumping by sending out electrical pulses. The muscle contracts about 70 times per minute and, as it does so, it sends blood through the body.

Both sides of the heart function independently and blood from each side does not mix.

The right side of the heart receives de-oxygenated blood which has already been round the body. It then pumps this blood to the lungs, where it collects fresh oxygen. This new, oxygenated blood then travels to the left side of the heart, to be pumped around the body. The cycle then repeats.

Blood leaves the heart through the aorta and then travels through the arteries. These eventually split off into smaller blood vessels called capillaries to ensure that blood reaches all areas of the body. Deoxygenated blood then returns to the heart through veins.

Issues that can affect the heart

Diseases relating to the heart are very common and range considerably in terms of their severity.

Angina is a term used to denote pain arising from the heart. It is often seen as a warning of heart problems and indicates that blood supply to the heart has temporarily fallen below metabolic requirements.

Arteriosclerosis is a condition where the arteries harden and lose their elasticity. This, in turn, leads to higher blood pressure or hypertension. Without proper blood flow, problems such as angina (insufficient blood provided to heart tissue) can occur.

Atheroma is the build-up of fatty plaques on the artery wall, reducing the space inside the artery through which blood can flow. This only happens in arteries, not veins. The heart is supplied by three main coronary arteries so, if they get blocked up, the blood supply to the heart will be affected.

Atherosclerosis is a combination of fatty plaques and hardened arteries, and is very likely to be present in cases of heart attacks.

Heart attacks occur when blood flow to the heart is interrupted thus leading to damage or death of these muscle cells.

High blood pressure, or hypertension, refers to the rate at which blood is pumped around the body. It rarely has noticeable symptoms but, if left untreated, can increase the risk of developing serious heart problems, including heart attacks and strokes.

High cholesterol occurs when too much of this fatty substance is found in the blood. The problem usually occurs due to lifestyle factors like eating fatty foods, not exercising enough, being overweight, smoking and drinking alcohol, though it can, occasionally, be an inherited health problem.

Low blood pressure, or hypotension, is less commonly identified than hypertension and is considered less of a problem, as it won't cause heart attacks and strokes. It will, however, mean that organs are poorly supplied with blood. Feeling faint or dizzy, experiencing sluggishness, cold extremities and lethargy are all common symptoms of low blood pressure.

Strokes are caused by disturbances in the blood supply to the brain. Atheroma in the arteries supplying the brain is the most common cause of strokes.

How to keep the heart healthy

If you have concerns about your heart health, it is best to seek the advice of a doctor. For some general tips on how to keep the heart healthy, however, you can follow some of the advice below.


Take gentle exercise – this reduces the risk of developing heart problems and can be as simple as a fast-paced walk round the block.

Lose weight – this is a big risk factor for heart disease. To manage your weight, follow a fresh, balanced diet with wholegrains, fruit, nuts, vegetables, seeds, fish, poultry and meat. It is also a good idea to exercise on a regular basis.

Reduce stress – stress can negatively impact heart function, contributing to raised blood pressure. To de-stress, spend some time doing a hobby, listening to relaxing music or take up a new recreational activity. It can also be really helpful to talk to others about how you are feeling.

Give up smoking – smoking increases the risk of developing certain heart problems such as atherosclerosis and heart attacks.


Avoid too much salt – this can be a risk factor for high blood pressure. Try to use less in your cooking and avoid processed foods that tend to have a high salt content.

Reduce caffeine intake – this can also contribute to high blood pressure. Coffee, tea and energy drinks are all high in caffeine. Herbal teas and plain water make a healthier alternative.

Cut down on saturated fats – this is problematic for cholesterol levels and blood pressure. Saturated fats are found in the likes of butter, cheese and fatty meats.

Eat more fish – this contains omega-3 fats which are really good for the health of the heart.

Consume more fruit and vegetables – a varied diet, with plenty of vitamins and minerals, is beneficial for the heart.

Herbal remedies

Hawthorn and Garlic have traditionally been used to maintain normal heart function, blood pressure and circulation.

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