Our hearts have a big job. Despite their impressive task of keeping us alive every second of every day, they, too, have felt the consequences of the COVID-19 pandemic. They may have been damaged by the disease itself, or they've been indirectly impacted by the way we've had to change our lives and habits.

A little more than two years after the global COVID-19 pandemic was declared by the World Health Organization, researchers are still working to make sense of the respiratory virus' cascading effects through the body. Scientists are also discerning COVID-19's other, less direct impacts. Stress, lifestyle changes, more drinking and barriers to health care access -- in addition to the disease itself -- are affecting people's heart health and leading to an increase in heart disease. 

Heart disease describes more than a sudden heart attack -- it's a broad term for several conditions that impact the way the heart functions, and it can move hand-in-hand with other common health conditions, including diabetes. High blood pressure is a major risk factor for heart disease.

While heart disease is still the leading cause of death in the world, modern treatments and prevention efforts have led to a steady decline in the number of deaths over the last few decades. Now, the pandemic is threatening the progress made in heart health. When adjusted for age, the mortality rate for heart disease and stroke increased from 2019 to 2020 in the US, according to a study published in late March. The increase was highest for Black Americans, who had a fivefold increase compared to white individuals.

COVID-19 disease, which attacks the heart, blood vessels and other crucial body parts, is responsible for some cases of heart disease and damage. But the reaching, everyday factors that make or break our health, including the ability to make an appointment or other social determinants of health, are also likely to have played a role in the increased mortality seen in the study, says Dr. Amy Pollak, a cardiologist at the Mayo Clinic.

"There have been significant changes in most of my patients with regards to how much they're exercising or dietary changes at some point over the last two years," Pollak says. "And that can impact our blood pressure, blood sugar and cholesterol -- as well as just changes in activity impacting our health and our stress levels."

According to a February survey by the Cleveland Clinic, 40% of Americans have experienced at least one heart-related issue since the beginning of the pandemic, which includes things such as shortness of breath or increased blood pressure.

Here's how the pandemic has taken hold of the heart.

How stress and social isolation hurt the heart

Stress releases cortisol, a hormone that, over time, can increase cholesterol, blood sugar, blood pressure and triglycerides -- all of which can increase the risk of heart disease. 

For better or worse (mostly for worse), our body keeps score of stress. As we progress into year 3 of the pandemic, most people have experienced some degree of stress stemming from loss, grief, boredom, complacency or other emotions. While our collective mental health has plummeted, the pandemic has also contributed to more daily stressors in some people's lives that may be less dramatic and harder to pinpoint, by way of homeschooling, job changes or fear of getting sick, for example. 

Stress can also zap your energy and leave you feeling fatigued, which can lead to other factors that negatively impact heart health, such as overeating, lack of exercise and not taking medications as prescribed. Inactivity (which is common among people stuck at home, or two years away from their favorite exercise group or gym) increases your risk of coronary artery disease, or a buildup in the vessels that supply blood and oxygen throughout the body.

Social isolation and loneliness have also marked much of the COVID-19 pandemic, with older adults shouldering much of the burden even before COVID-19. A study on heart disease risk, social isolation and loneliness found that post-menopausal women who experienced both were 27% more likely to develop heart disease than their peers. While the study was conducted prior to the pandemic, Pollak fears the effects will be even more pronounced now. And also harder to describe from a medical standpoint.

"We don't understand the 'why' as much," Dr. Pollak says. "How much of this is related to, if you're feeling socially isolated, are you also having changes in your physical activity, or your diet. Or are you less likely to make those positive choices for monitoring your blood pressure?" 

But the role of chronic stress and the toxic effect too much cortisol has on our bodies is likely very much tied to people's experiences in social isolation. 

"We do know that chronic stress, separate from diet and lifestyle choices, is independently associated with a higher risk of heart attack or stroke," says Pollak. 

Stress, loneliness or other emotions may also have us reaching for the bottle. About one-fourth of America reported drinking more to cope with the stress of the pandemic, combining another cultural shift in our views on alcohol with potentially negative consequences for our heart health.

Dr. Arun Sridhar is a cardiologist and an assistant professor of cardiology at the University of Washington School of Medicine. He sees the rise in drinking as a rise in risk for atrial fibrillation -- an irregular, oftentimes rapid heartbeat -- which is one of the most common types of arrhythmia (irregular heartbeat). 

"We have seen an increase in the number of patients with atrial fibrillation and cardiac arrhythmias," Sridhar says. But he can't say for sure all of these cases are a direct result of alcohol, as there are other factors besides people drinking more at play -- including people not coming in for follow-up care for an existing heart condition, or delaying care all together. 

"All these things have increased the number of patients coming in for arrhythmia treatment these days," Sridhar says.

The heartbreak of delayed care

As hospital capacities reached their limits at different points the last couple of years and appointments for nonemergencies were canceled, the inability to make it in for a blood pressure check or other primary care appointment is also impacting American hearts.

Sridhar says he's worried about the delay in health care for what he calls "long-term maintenance issues." A major cardiac event, such as a heart attack or even heart palpitations, are usually notable enough to seek help and care, he says. But when it comes to managing high blood pressure, diabetes or other direct risk factors for heart disease, patients weren't coming in for care, either out of fear of the cost or exposure at the hospital. 

But perhaps patients don't need to come in to manage their blood pressure, as long as they have the right tools at home. Some research from the UK suggests that patients who are equipped with a blood pressure monitor and work with a health care team through video for medication consultation and education may be able to manage their hypertension more effectively.

The barrier to this type of telemedicine care for more people, of course, are the devices. Patients need to be connected to whatever video system their provider requires, a blood pressure monitor (which may run you from $30 to $200) and someone to help with the setup, if needed.

How long COVID affects the heart

Some people who've recovered from COVID-19 have yet to feel like their old selves again, plagued by lingering symptoms that interfere with their daily lives. For people living with long COVID, answers about its cause and potential treatments remain in limbo while new symptoms are added to the extensive list almost daily.

Arrhythmia, or abnormalities of your heartbeat, is one symptom of long COVID. Another is the out-of-breath feeling some people get easily doing something that, pre-infection, wouldn't have been a strain for them. This breathlessness is caused by changes to the heart's capacity to "augment the output," Sridhar says, or changes to how much energy we can exert.

A large study published last month in the journal Nature outlined the sweeping effects of COVID-19 on heart health. The study looked at data from millions of health records in the US Department of Veteran Affairs database. Not only can COVID-19 impact the heart vessels and damage the muscle when people are acutely ill, but even 30 days after infection, people had a higher risk of various types of cardiovascular disease, including cerebrovascular disorders, dysrhythmias, ischemic and nonischemic heart disease, pericarditis, myocarditis, heart failure and thromboembolic disease. 

"If anybody ever thought that COVID was like the flu, this should be one of the most powerful data sets to point out it's not," Dr. Eric Topol, a cardiologist at Scripps Research told Science.

The heart is one of the most important organs in our body (second only, maybe, to the brain). Given the irreplaceable role it plays in our ability to sustain life, even little disruptions to the way its systems function can impact daily life. More research, and time, is needed to measure the entire influence of COVID-19 on the heart. 

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.