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What is heart failure?

What is heart failure?

Heart failure sounds alarming but it doesn’t mean your heart has stopped working or is going to suddenly stop beating. If you have heart failure – or, as it’s sometimes called, congestive heart failure – it means your heart isn’t working to pump blood around your body as well as it should, and needs some support.
When someone has heart failure – which is classed as one type of heart disease or cardiovascular disease – their heart muscle isn’t as strong as it should be. Normally a certain amount of blood enters your heart and is pumped out again with each heartbeat. The heart is made up of two pumps, one on the right and one on the left. The right pump receives blood from the body and sends it to the lungs where it collects oxygen. Then the left pump receives the oxygen-rich blood and pumps it back around the body.
But when your heart muscle is weak, your heart can’t pump the right amount of blood each time it beats. This means your organs, muscles and other tissues don’t get the right amount of oxygen and nutrients they need to work effectively. It means waste products in your blood aren’t sent to your kidneys and lungs for disposal as efficiently as they should too.

Heart failure: UK statistics

According to Patient UK, around 920,000 people in the UK currently have heart failure and there are approximately 67,000 admissions to hospitals for heart failure in England and Wales each year (i). The condition is more common in older adults, affecting (ii):

  • One in 35 people aged 65 - 74 years

  • One in 15 people aged 75 - 84 years

  • One in seven people aged 85 years or older

On average, people are first diagnosed with heart failure when they are 76 years of age, with the condition affecting more women than men (ii). 

Types of heart failure

Heart failure can be chronic or acute. Most people affected have chronic heart failure, which means the symptoms have been happening for some time. Sometimes, however, heart failure can develop and make you unwell suddenly, or if you already have heart failure it can become much worse or unstable very quickly. This is often referred to as acute heart failure. People with acute heart failure are usually admitted to hospital, whereas if you have chronic heart failure you’ll usually be treated in the hospital as an outpatient.
As well as acute and chronic there are other types of heart failure that are classed according to the part of the heart that’s affected and/or how much blood the heart pumps out with each beat. There are a number of terms heart specialists and other healthcare professionals use to describe the different types of heart failure, including:

  • Heart failure with reduced left ventricular systolic function (HFREF) is when the bottom left chamber of the heart is weak and unable to work properly.Commonly known as left-sided heart failure.

  • Heart failure with preserved ventricular function (HFPEF) is when the heart pumps normally but has problems filling with blood.

  • Right heart failure is when the right side of the heart is weak and unable to pump enough blood to the lungs. Commonly known as right-sided heart failure.

  • Heart failure with reduced ejection fraction (HFrEF) is when less than 40 percent of the normal amount of blood is pumped out.

  • Heart failure with mildly reduced ejection fraction (HFmrEF) – also called heart failure with mid-range ejection fraction – is when between 40 and 49 percent of the normal amount of blood is pumped out.

  • Heart failure with preserved ejection fraction (HFpEF) is when more than 50 percent of the blood is pumped out.

According to the National Institute of Health and Care Excellence (NICE), about 50 percent of people with heart failure are affected by either reduced ejection fraction or preserved or mildly reduced ejection fraction (ii).

What are the symptoms of heart failure?

The symptoms of heart failure vary from one person to another, with the main ones including:

  • Breathlessness (this is often a result of pulmonary oedema, which is when fluid collects in your lungs, or it may happen when you exert yourself physically)

  • Tiredness and feeling weak, even when you’re resting or after the smallest amount of activity, plus exhaustion after exercising

  • Swelling in your legs and ankles (again this is caused by a build-up of excess fluid, called oedema or edema, which may worsen throughout the day)

  • Lightheadedness and feeling faint

Other, less common, symptoms include:

  • Persistent cough (often worse at night)

  • Weight gain (caused by retaining too much fluid) 

  • Poor appetite, often accompanied by feeling full all the time or bloating (this can be caused by fluid accumulating in the digestive organs) 

  • Weight loss

  • Wheezing 

  • Confusion 

  • Heart palpitations (pounding, fluttering or irregular heartbeat) 

  • Rapid heart rate  

According to the NHS, some people with heart failure may also experience feelings of depression and anxiety (iii). 
Many people who develop heart failure can remain stable for years when they’re treated for their condition. In some cases, where the cause is reversible, heart failure can even be cured (read on to find out what causes heart failure). In others, the symptoms become gradually worse. However, the good news is that modern treatments have greatly improved the outlook for many people with heart failure.

What causes heart failure?

There are lots of different things that can cause heart failure, and in many cases it’s caused by more than one problem affecting the heart simultaneously.

The most common causes of heart failure include:

  • Heart attack (because of the damage it can do to your heart and how effectively it pumps blood)

  • Cardiomyopathy (a group of conditions that affect the heart muscle)

  • Myocarditis (inflammation of the heart muscle, which can lead to cardiomyopathy)

  • High blood pressure (if your blood pressure is high it puts a strain on your heart, which can eventually result in heart failure)

There are many other less common causes too, including:

  • Arrhythmias (abnormal heart rhythms, which is when your heart beats irregularly. too quickly or too slowly – one type of arrhythmia is called atrial fibrillation)

  • Heart valve problems (these can impede the flow of blood through your heart)

  • Congenital heart disease (heart problems that you’re born with)

  • Amyloidosis (a build-up of abnormal proteins in your organs – when this affects your heart it’s called cardiac amyloidosis, or sometimes ‘stiff’ heart syndrome)

  • Anaemia (when your blood lacks enough oxygen-carrying red blood cells)

  • Thyroid problems (including an underactive or overactive thyroid gland)

  • Pulmonary hypertension (high blood pressure in the blood vessels that supply your lungs)

  • Drinking too much alcohol

  • Some types of chemotherapy (treatment for cancer)

  • Drug misuse (either prescribed or recreational drugs)

  • Diabetes (this can place a strain on your heart over time)

In some people, however, there is no obvious reason why the heart muscle becomes weaker – this is known as idiopathic heart failure.

How is heart failure diagnosed?

If you go to your doctor with symptoms of heart failure they will usually examine you to check for things like a faster-than-normal pulse rate, signs of fluid retention (swollen ankles, for example) and an enlarged heart. These are all things that happen with heart failure, but as they can be caused by other conditions too you’ll usually also need tests to confirm that you have heart failure.

How do doctors test for heart failure?

The first test is typically a blood test, which can show how well your heart is working. If your results suggest you may have heart failure your GP will usually refer you to a heart specialist for more tests, including:
Further blood tests (these may, for instance, check for a type of hormone in your blood called BNP, which your heart releases when it’s stressed, plus how your kidneys are functioning)

  • An electrocardiogram (ECG) to test your heart’s electrical activity

  • An echocardiogram (ultrasound scan of your heart)

  • Breathing tests to check your lung function

  • A chest x-ray

  • Cardiac MRI (an advanced scanning technique)

  • Coronary angiogram (this is often carried out after someone has a heart attack to check the blood vessels around the heart muscle)

  • Myocardial perfusion scan


Heart failure stages

If you’re diagnosed with heart failure your specialist may talk to you about the class of stage of your condition. There are four stages of heart failure that vary according to how severe your symptoms are:

Stage 1 heart failure (very mild)   

At this stage there may not be any symptoms, with people diagnosed after having tests for other reasons.

Stage 2 heart failure (mild)

This is when you don’t have symptoms when you’re resting, but normal physical activity such as walking may cause some breathlessness, tiredness or heart palpitations.

Stage 3 heart failure (moderate)

Again you’re comfortable when you’re resting, but minor physical activity can cause symptoms.

Stage 4 heart failure (severe)

This is when any type of physical activity causes symptoms, plus you may also have symptoms when you’re at rest.

Treatments for heart failure 

Most people with heart failure will need to be treated, usually for the rest of their lives, to keep their symptoms under control. This could include medication, surgery and lifestyle changes. Depending on what’s causing your heart failure you may also need to be treated for an underlying condition, with treatments including blood pressure-lowering medicines and cholesterol-lowering medicines. 

What is the first line treatment for heart failure?

The most common treatment is medication, with people with heart failure often taking two or three different types.
There are many medicines used to treat heart failure. Some of the main ones include:

  • ACE inhibitors (these relax your blood vessels, making it easier for your heart to pump blood)

  • Angiotensin-2 receptor blockers (these are similar to ACE inhibitors)

  • Beta-blockers (these slow down your heart rate)

  • Diuretics (also known as water tablets, diuretics make you pass more urine, which can help relieve the build-up of fluids)

  • Digoxin (usually only prescribed for those who have tried other treatments but still have symptoms, digoxin helps to strengthen your heart muscle contractions and slow down your heart rate)

  • Mineralocorticoid/aldosterone receptor antagonists (MRAs help you to pass more urine and lower your blood pressure)

  • Ivabradine (often used as an alternative to beta blockers, this helps slow down your heart)

  • Sacubitril valsartan (this is a medicine for people with severe heart failure)


Pacemaker for heart failure 

A small number of people with heart failure may be advised to have a medical device  implanted in their chest to help control or monitor their heart’s rhythm.
These devices include pacemakers, which are recommended for people whose hearts beat too slowly. Pacemakers monitor your heart continuously and send pulses to your heart to keep it beating normally. Implantable cardioverter defibrillators (ICDs) are also used in some people with heart failure. These detect abnormal heart rhythms and help your heart to get back to a regular beat. Other devices include pulmonary artery pressure sensors, which send blood pressure measurements to your care team.

Heart failure surgery

Some people with heart failure need surgery to treat their condition, with current operations including heart valve surgery, coronary angioplasty (where a tiny balloon is inserted in a narrowed or blocked artery to keep it open), coronary bypass and heart transplant – though the latter is only usually considered for people with severe heart failure who can’t be treated with medication or other types of surgery.

What is the average life expectancy with heart failure?

How long you’ll live after developing heart failure will depend on a number of factors, including your age, the stage of your condition and how well your heart is working. In general, however, the British Heart Foundation reports that 80 percent of heart failure patients survive for a year, 48 percent survive for five years and 26 percent survive for 10 years.

Managing  heart failure

Your GP or specialist may also recommend ways you can help yourself to reduce your symptoms and slow the progression of your condition, as well as improve your quality of life in general. Indeed, making just a few simple lifestyle changes could make a big difference to how well you feel and how easily you can carry on with your day-to-day activities.

Eat a balanced diet

Try to eat as healthily as you can, having plenty of fruit and vegetables (five or more portions a day), good amounts of starchy foods and some dairy and protein foods with limited amounts of saturated fat, salt and sugar. If you need more advice, ask your doctor or specialist for details about dietary changes you may need to make because of your condition.

Give up smoking

If you’re a smoker, your GP or specialist will offer you advice on quitting, since smoking releases chemicals including nicotine, carbon monoxide and tar – all of which make your blood vessels narrow and put added pressure on your heart. If you need more tips and advice on giving up, read our guide to stop smoking


Cut down on salt

Having too much salt in your diet may make your symptoms worse because excess salt encourages your body to retain more water (fluid retention). Try to cut down on the amount of salt you use – for instance, if you regularly add salt to your food at the table, try using more herbs and spices instead. Also be wary of processed foods, many of which contain a lot of salt (always try to check food labels to find out how much salt or sodium any item of processed food contains, and steer clear of those that are high in salt/sodium wherever possible – look out for red indicators on traffic light food label systems). Do not, however, switch to lo-salt substitutes without your doctor’s advice, as they may affect your medication. 

Drink less alcohol

Having too much alcohol may also damage your heart muscle, as it reduces the heart muscle’s ability to contract. Stick to current guidelines for safe alcohol intake, which state you shouldn’t drink more than 14 units of alcohol a week on a regular basis (also space your units out evenly over three or more days if you do drink this much).
Find out more information about cutting back on alcohol and how many units are in popular drinks by reading our guide to alcohol misuse

Stay active

When you’re first diagnosed with heart failure you may be advised to take it easier for a while. Once your medication starts taking effect and your symptoms improve, however, your doctor or specialist will usually encourage you to be more active. Try some gentle exercise to start with, and build up to 150 minutes of moderate activity a week (this means you should get warm and feel your heart beating faster, but you shouldn’t become breathless – if this happens, stop what you’re doing immediately).

Keep your weight down

It’s important to watch your weight if you have heart failure as being overweight can put a strain on your heart. Your doctor or specialist will advise you about losing weight if you need to. If you’re not overweight, eating healthily and staying active can help keep your weight within the normal range. You may also be advised to weight yourself regularly, even if you’re not overweight, as a sudden gain in weight may be a sign that you’re building up too much fluid in your body (if this happens, tell your doctor or specialist as soon as possible).

Get your jabs  

Ask your GP if you’re up to date with your flu and pneumonia vaccinations, as either of these conditions can increase your risk of developing heart failure complications (you should be having an annual flu jab but the pneumonia jab is a one-off vaccine).

Drink the right amount of fluid  

If you’re taking diuretics (water tablets), you may feel more thirsty than you used to. However it’s important not to drink too much fluids when you have heart failure – unless your doctor or specialist has recommended otherwise, aim for no more than 1.5 - 2 litres of fluids a day (this can include tea, coffee, water, juice and other drinks).

Can heart failure be prevented?

Many lifestyle measures could help reduce your chances of developing heart failure in the first place, including:

  • Eating healthily

  • Avoiding smoking

  • Drinking alcohol in moderation

  • Taking regular exercise 

  • Controlling your blood pressure 

  • Managing diabetes if you’re diabetic


Heart failure and energy drinks

Some evidence suggests that there is a connection between the overconsumption of energy drinks and heart failure.¹ In fact, excessive consumption of energy drinks has also previously been linked to cardiovascular conditions such as tachycardia and myocardial infarction. Experts have found that a possible factor linking heart failure and energy drinks is the overstimulation of the sympathetic nervous system as a result of extreme caffeine consumption. As guidance for healthy adults, it is recommended that the maximum daily dose of caffience is 400mg a day — comparable to a few cups of coffee.


Supplements for heart health

As well as having a healthy lifestyle, several nutritional supplements may help support your heart and keep it in good condition. Some of these include:

High-strength fish oils

A number of studies have looked into whether or not the omega-3 fatty acids found in oily fish may help protect the heart from disease, including heart failure. Indeed, experts writing in the medical journal JACC: Heart Failure have suggested there’s impressive scientific evidence to support the use of omega-3s in the treatment and/or prevention of heart failure (iv). A review of 12 clinical studies has also concluded that while taking omega-3 supplements didn’t reduce the number of people first hospitalised for heart failure, it did reduce subsequent hospitalisations when compared with a placebo (v). Another review, this time of nine studies, came to the conclusion that overall, omega-3 supplements might be beneficial for people with heart disease – especially those who have dilated cardiomyopathy – but that further studies were needed (vi).
If you’re a vegetarian or vegan you can still benefit from an omega-3 supplement, thanks to the availability of products that contain the natural triglyceride (TG) form of omega-3, which is sourced from plant organisms called microalgae rather than fish.

Coenzyme Q10

Also called ubiquinone, CoQ10 is a powerful antioxidant that’s found in every cell in the body, with high concentrations found in the muscles of the heart. One study suggests that people with heart failure may benefit from also taking CoQ10 (vii), but other studies have had more mixed results, with a 2021 review stating that there’s currently no convincing evidence either way regarding supporting or refuting the use of CoQ10 for heart failure. However another report suggests that as a therapy for cardiovascular disorders such as chronic heart failure, CoQ10 appears to be safe and well tolerated (viii).


This mineral is required by the body for muscle relaxation and is thought to be important for the regular functioning of heart muscle. Taking magnesium supplements regularly may also help to treat high blood pressure (ix).

Vitamin D

Probably best known for its importance in bone health, vitamin D is also needed for heart health, with experts claiming that chronic heart failure is often linked to vitamin D deficiency (and also that having low vitamin D levels can cause a worse outcome in those with heart failure) (x).
Having low levels of vitamin D, however, is common, including in the UK. As a result, Public Health England advises all adults and children over the age of one year old to consider taking a daily 10mcg supplement of vitamin D during the autumn and winter months (xi).
A lot of people may also need to take vitamin D supplements throughout the year, especially those who rarely expose their skin to the sun (for instance, people who spend most of their time indoors or those whose skin is always covered when they’re outside). People with dark skin from African, Afro-Caribbean and South Asian backgrounds should consider taking vitamin D all year round too, PHE advises.
The recommended supplement form of vitamin D is vitamin D3 or cholecalciferol, as it’s the natural form of vitamin D that the body makes when it’s exposed to sunlight. Vitamin D3 supplements are available in tablet form, plus you can now get them in veggie-friendly drops too. Most vitamin D3 supplements are made from the fat of lamb’s wool, however, which means they’re unsuitable for vegans. Thankfully vegan vitamin D3 supplements – sourced from lichen – are now more widely available.

Vitamin K2

There isn’t a great deal of vitamin K2 in typical Western diets, particularly if you eat a lot of processed foods. However it appears to have a role in heart health, as it may help reduce calcium build-up in the arteries around the heart. One study of more than 16,000 women has also concluded that vitamin K2 may be associated with a lower risk of coronary heart disease in general (xii).
Vitamin K2 is found in foods such as hard and soft cheeses, egg yolks, curd cheeses, chicken and goose liver, but you can also find it in nutritional supplements.

For more information about heart health

Looking for information on heart health conditions as well as advice on keeping your heart in good working order? Try reading some of the other articles in the heart health section of our pharmacy health library



  1. Available online:

  2. Available online:

  3. Available online:

  4. . Omega-3: The Overlooked Evidence-Based Therapy for Heart Failure. J Am Coll Cardiol HF. ;10(4):235-237. Available online:

  5. . Omega-3 supplementation and heart failure: A meta-analysis of 12 trials including 81,364 participants. Contemp Clin Trials. ;107:106458. Available online:

  6. . The Role of Omega-3 Polyunsaturated Fatty Acids in Heart Failure: A Meta-Analysis of Randomised Controlled Trials. Nutrients. ;9(1):18. Available online:

  7. . Coenzyme Q10 treatment in serious heart failure. Biofactors. ;9(2-4):285-9. Available online:

  8. . Coenzyme Q10 treatment of cardiovascular disorders of ageing including heart failure, hypertension and endothelial dysfunction. Clin Chim Acta. ;450:83-9. Available online:

  9. . Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo Controlled Trials. Hypertension. ;68(2):324-33. Available online: . Oral magnesium supplementation reduces ambulatory blood pressure in patients with mild hypertension. Am J Hypertens. ;22(10):1070-1075.

  10. . Effects of Vitamin D on Cardiac Function in Patients With Chronic HF: The VINDICATE Study. J Am Coll Cardiol. ;67(22):2593-2603. Available online:

  11. Available online:

  12. . A high menaquinone intake reduces the incidence of coronary heart disease. Nutr Metab Cardiovasc Dis ;19(7):504-10. Available online:

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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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