Long COVID isn’t the only opportunity for the virus to wreak havoc later than expected.

Even a mild case of COVID can lead to an increased risk of cardiac issues like heart failure and stroke for at least a year, according to a March study by Veterans Affairs Department researchers. Deaths from heart attacks soared during pandemic surges—especially among those ages 25-44, a usually low-risk population, Cedars-Sinai researchers announced last fall. And emerging data continue to support these and similar findings.

In a bid to determine why and how COVID can affect the heart, Dr. Andrew Marks, a cardiologist and biophysics professor at Columbia University, and Steven Reiken, a research scientist in his lab, studied heart tissue from people who died of COVID, in addition to the hearts of mice that had been infected with COVID.

Among their findings, which they’ll present Monday at the 67th Annual Biophysical Society Meeting in San Diego:

Heart tissue from humans shows increased levels of oxidative stress and inflammation, and changes in calcium levels due to damage to the system that regulates them in the heart. Such alterations can lead to arrhythmia or heart failure, according to the researchers.

Chest pain and tachycardia, or an unusually fast heart beat, are common long-term amongst COVID survivors.

Heart tissue from mice shows an increased percentage of fibrosis and dilation of fibers—a common signal of early cardiomyopathy, which makes it more difficult for the heart to pump blood and can result in heart failure.

The death of heart cells and blood clots in the hearts of mice who had been infected with COVID-19 were also observed.

“Doctors should be aware of heart changes related to COVID-19 infections and should be looking for them,” Marks says. He hopes his research leads to increased awareness among medical providers of the virus’s potentially stealthy cardiac fallout—and, eventually, treatments for those whose hearts have been damaged by the pathogen.

How to maintain heart health in the era of COVID

With COVID here to stay, what can the average person do to protect their heart?

Keeping heart-healthy pre-COVID looks largely the same during COVID, Dr. Michelle Albert, president of the American Heart Association, tells Fortune.

“Maintaining optimal cardiovascular health is important at every stage of your life and can help you enjoy a longer, healthier life,” she says. “Better cardiovascular health has been associated with decreased risk for heart disease, stroke, cancer, dementia, and other major health problems.”

Maintaining good heart health can curb your COVID risk, she adds, as conditions that increase one’s risk of severe COVID outcomes, like obesity and high blood pressure, often overlap with poor heart health.

Albert and the AHA recommend the following:

Control blood pressure

Eat healthily

Maintain a healthy weight

Don’t smoke or vape

Exercise

Get adequate sleep

Maintain healthy levels of cholesterol and lipids

Maintain healthy blood sugar levels

The AHA also recommends that people stay up to date with their COVID vaccinations and boosters, and to call 911 if they, or someone else, are experiencing signs of heart attack or stroke.

In addition, Marks recommends continued masking in public. “There is still a lot we don’t understand,” he says. “The public should be aware of the risks.”