Does your heart rate increase when having a heart attack

We explain how Covid can affect your heart and circulatory system, and what to do if you experience symptoms such as a fast heart rate or heart palpitations.

Even though coronavirus was initially thought of as a respiratory illness, we now know that in severe cases, it can affect other organs and systems in your body. 

The infection (and the way your body responds to it) can cause damage to the heart, lungs, kidneys, brain, liver, and gastrointestinal system, as well as other systems in your body.

While we know much more about how Covid affects the body than ever before, there is still more we need to understand, and more research is being carried out.

How does coronavirus affect your heart and circulatory system?

Covid-19 can affect your heart and circulatory in many ways, including a faster heart rate and heart palpitations, blood clots, heart damage due to a lack of oxygen and nutrients, inflammation of the heart muscle and lining, or Takotsubo syndrome (broken heart syndrome).

Many of the symptoms that people can experience are thought to be linked to the virus damaging endothelial cells (the cells which line all the blood vessels in our body). All parts of the body need a healthy blood supply to work properly, so damage to your blood vessels has the potential to cause abnormal blood clotting, ‘leaky’ blood vessels, and reduced blood flow throughout the body – which can lead to a range of symptoms.

This could be a factor in why people with existing heart and circulatory conditions are at a higher risk of complications from Covid-19, as they may already have, or be at risk of damage to the endothelium (the inner lining of the blood vessels). But the virus can also cause heart and circulatory complications in those without existing heart disease. This is an area where we are still learning more and more research is being carried out.

A fast heart rate or heart palpitations after Covid

Covid-19 can cause your heart rate to become fast or irregular in response to fever or inflammation, as your heart works harder to pump more blood around your body to fight the infection.

Changes to your heart rate can also happen for other common reasons, including dehydration, anxiety, medications, as well as other health conditions. Learn more about what things can cause your heart rate to become fast.

Palpitations are not usually a cause for concern, but it’s a good idea to get medical attention if you're worried about them, or if the palpitations last a long time, do not improve or get worse, or if you have a history or heart problems. 

Researchers are still looking into why people might experience changes to their heart rate after Covid, but it’s thought that this could be due to the virus and the immune response affecting the autonomic nervous system (rather than the heart muscle itself). This is the part of the nervous system that works automatically to regulate essential body processes, like blood pressure, heart rate and breathing rate.

• Learn more about when heart palpitations might be a cause for concern 
• Find out more about the symptoms of long Covid and some tips for recovery

Call 999 if you feel palpitations or a faster heartbeat and you also have chest pain, or dizziness, or blackouts.

Blood clots

People who develop severe illness from Covid-19 are at a higher risk of blood clots. This is thought to be due to damage to the blood vessels, either directly caused by the virus or as a result of the body’s immune response to the infection. Depending on where in your body they are, blood clots can cause serious problems such as deep vein thrombosis, clots in the blood vessels in the lung (pulmonary embolism), heart attack or stroke.

• Read more about how coronavirus affects the blood vessels 

Lack of oxygen and nutrients causing heart damage

Covid-19 can cause fever and inflammation, which places extra stress on the heart as your body fights the infection. This can also cause your heart rate to become fast or irregular.

If the Covid infection is severe enough that it damages the lungs, this can reduce the amount of oxygen that reaches the heart. As the virus and the immune response to it can also damage the cells that line the blood vessels, this can also cause clots in the blood vessels that supply the lungs and limiting the supply of oxygen and nutrients to the heart.

This extra demand on the heart, paired with the lack of oxygen and nutrients, can cause damage to the heart muscle. We know that patients in hospital with severe cases of coronavirus who have heart muscle damage (as shown by blood tests) have a higher risk of dying.

In some patients, further tests called echocardiograms have found that the heart isn’t pumping as well as it should (heart failure).

What isn’t always clear is whether that damage was already there, although many researchers believe that the virus can damage the heart muscle function. It's important to understand that this particular study only looked at people who needed hospital treatment for Covid-19, and who also had raised troponin levels in their blood (troponin is also used to diagnose heart attacks, and is usually a sign of injury to the heart).

More reassuringly, a BHF-funded study published in May 2021 found that mild cases of Covid-19 do not appear to be linked to lasting heart damage.

Inflammation of the heart muscle and lining

Covid-19 can cause inflammation of the heart muscle (myocarditis) and heart lining (pericarditis). Myocarditis and pericarditis can also be caused by other viral infections, not just Covid-19.

A study led by researchers at the BHF Cardiovascular Research Centre at the University of Glasgow, published in May 2022, found that 1 in 8 people who were hospitalised with Covid-19 were later diagnosed with myocarditis. The study also showed that in addition to heart inflammation, severe Covid can cause inflammation across the body and damage to the kidneys.

The research, which followed 159 people who were hospitalised between May 2020 and March 2021, found that the risk of myocarditis was much higher in those who were severely ill (needing a ventilator or treatment in intensive care).

Almost all of the patients involved in this study were unvaccinated, which means they were already at a higher risk of severe illness from Covid-19. This research was carried out before the Omicron variant was detected in the UK, and we know that generally people who catch this variant experience milder symptoms.

Earlier in the pandemic, scientists thought that myocardiis may be caused by the virus attacking the heart muscle cells directly. But as we learn more, many researchers now think this damage to the heart can be the result of the immune system overreacting to the infection. For example, BHF-funded researchers at the University of Cambridge have been investigating how cytokines (molecules that the cells in your immune system use to communicate with each other, which are known to be involved in inflammation) found in the blood of people with Covid-19 can prevent heart muscle cells from working properly.

While many people can have mild injury to the heart without any symptoms, in some severe cases it can cause shortness of breath, chest pain or abnormal heart rhythms. If you notice any of these symptoms, you should seek medical advice.

Takotsubo syndrome ("broken heart syndrome")

Takotsubo syndrome, sometimes known as "broken heart syndrome", happens when the left pumping chamber of the heart rapidly changes shape and becomes larger, weakening the heart so it’s less able to pump blood around the body. It often occurs in response to an emotional or stressful event. In many cases, the heart recovers.

During the pandemic there was a rise in the number of people being diagnosed with Takotsubo, not all of whom have had Covid-19. However, it’s worth remembering that overall this condition is still relatively rare – it’s been estimated that around one in fifty people who go to hospital with chest pain symptoms actually have Takotsubo. More research needs to be done to understand the reasons behind this increase, but it’s thought that in addition to the stress of the pandemic, inflammation caused by the body’s immune response to the virus could also be behind the link.

It’s also possible that this level of Takotsubo syndrome was present before, but people have become more aware of it.

How does coronavirus get into the body?

Like many other viruses, coronavirus is passed on through tiny droplets that enter your body through the eyes, mouth and nose. Spiky proteins on the surface of the virus help it to attach to healthy cells, where it can quickly multiply.

How does coronavirus affect the lungs?

In severe cases of Covid-19, the infection moves down the respiratory tract to the lungs, where it can cause pneumonia. If you get pneumonia, your lungs might not be able to supply as much oxygen to the bloodstream, so you may need hospital treatment. It’s now also understood that one of the ways coronavirus can prevent the lungs from working properly is through damaging small blood vessels in the lungs. This can cause blood clots and fluid to accumulate in the lungs, which means they are less able to get oxygen into the body.

If you develop pneumonia, in addition to the common signs of Covid-19, you may notice symptoms like a rapid heartbeat, breathlessness, or pain in your chest. If you experience any of these symptoms when you are ill with Covid-19, you should call 999.

How long does it take to recover from Covid?

Most people who get Covid-19 either have no symptoms at all, or a mild illness which feels similar to a cold or flu. If your infection is mild, you should feel better in a few days or weeks.

A small number of people develop a more severe illness which means they need to go to hospital. If you have been seriously ill with Covid, this may increase the time it takes to recover. 

Some people are also experiencing symptoms that last for months after the initial infection. This is referred to as ‘long Covid’, which can include symptoms such as fatigue, feeling short of breath or having heart palpitations. While long Covid is more common in people who needed hospital treatment due to Covid, it’s still possible to develop long Covid after a mild infection.

• Learn more about the symptoms of long Covid and some tips for recovery
• Find out when you should still seek medical help for symptoms that could be heart related 

Can coronavirus cause diabetes?

There is some evidence of a link between Covid-19 and an increased risk of developing diabetes in the weeks after infection.

Research led by scientists at King’s College London, including BHF Professor Ajay Shah, suggests that the risk of diabetes is 81% higher in the four weeks after a Covid-19 infection, but this falls back towards pre-Covid risk levels after five to six months. The study, published in July 2022, compared the health records of over 428,000 Covid patients with people of the same age and gender, who had not tested positive for Covid.  

While this was a large study with important findings, it doesn’t prove that Covid itself causes diabetes. There may be other reasons for this link. For example, it’s possible that some of the Covid patients already had diabetes, and catching the virus also made them more likely to be diagnosed. This could be because catching Covid progressed their diabetes, or because they were in more frequent contact with their doctor. 

There were also other differences between the Covid-19 cases and the control group. For example, the Covid cases in this study tended to have more pre-existing health conditions and were less healthy in general. These factors could mean they were already at a higher risk of diabetes before catching Covid. It’s also possible that some of the control group also had Covid without realising it (the Covid group was based on those with the illness confirmed by a PCR test), which could affect the results.  

Some small studies have also suggested that Covid-19 can cause similar effects to diabetes. Diabetes is a condition where your body doesn’t produce enough of the hormone insulin or can’t use the insulin it does make, which can raise levels of glucose (a type of sugar) in your blood. These studies suggest that Covid-19 can cause insulin-producing cells to die or to produce less insulin. These studies have mostly been carried out in the lab, not in actual people, so more research is needed to confirm this theory.   

More research is needed to further understand the link between diabetes and Covid-19, including what causes the link, and whether these changes are permanent or reversible. In the meantime, you may want to consider steps to reduce your diabetes risk if you’ve recently had Covid, such as a heart- healthy diet and increasing activity levels. 

If you experience any symptoms of diabetes, contact your GP.

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