Heart disease is still the No. 1 cause of death for adults in the U.S. Here's what you need to know.

Heart disease is the leading cause of death for men and women in the U.S. In fact, one person dies every 34 seconds in the country from heart disease, which was responsible for one in every five deaths in 2020.

But despite how common —and deadly — heart disease is, many people don't know all that much about it. "Heart disease is any problem that takes place in the heart," Dr. Columbus Batiste, a cardiologist with Kaiser Permanente, tells Yahoo Life. "That could mean the arteries, it could mean the electrical system, it could mean the pump. So just like your car, you have different aspects to the heart that can run into problems."

Heart disease affects men and women, but it disproportionately impacts communities of color, Batiste says. It also tends to happen alongside other illnesses. "Heart disease ... often runs with high blood pressure, it runs with diabetes, it runs with high cholesterol, it runs with inactivity, it runs with stress, which impacts so many Americans," he says.

The Centers for Disease Control (CDC) says one of the largest groups affected by heart disease is 65 and older.

But Batiste says that heart disease "sneaks up on you," making it important to have some awareness of this serious illness. So, what are the signs of heart disease to look out for? Here's what you need to know.