Many of us feel young at heart, but research shows the reality may be quite different.

Today nearly 69 million Americans are walking around at risk of heart disease, and heart disease is responsible for one in every four deaths across the United States. It’s also the world’s leading killer at 17.5 million people annually.

These statistics dovetail with a new study released by the Centers for Disease Control and Prevention in September. The study estimates that 75 percent of adults have a predicted functional heart age older than their actual age. On average, two in five women’s hearts are about five years older than their real age, and half of men have hearts that are eight years older.

What Is Heart Age?

Heart age is determined by actual age, body mass index, and a number of risk factors for heart attack and stroke including high blood pressure, high cholesterol, diabetes, smoking, an unhealthy diet, physical inactivity and obesity.

The riskier your profile, the “older” your heart is predicted to be.

While this is certainly not good news, it should not be discouraging because heart disease is very much lifestyle-driven. You can make your heart younger! You simply have to make changes to reduce your risk.

The concept of heart age was developed by experts who worked on the Framingham Heart Study, a long-term cardiovascular project that began in 1948 and is now in its third generation of participants. It was believed to be a need because doctors had a hard time framing heart disease risk in relative terms to clients. For example, a 60-year-old patient who is told he has a 20 percent chance of heart disease might think his odds are pretty good. However, if told his heart age is 10 years older than his actual age, that same patient is better able to conceptualize the problem—and be motivated to make changes to his lifestyle.

This was conclusively proven in a clinical trial in Europe. Those who calculated their heart age focused better on factors needed for improving their cardiovascular health, compared to receiving more general counseling for percentage of risk. Taking steps that led to a healthier lifestyle allowed them to get their heart age back to where it should be.

You can find out your heart’s age by using this online calculator, provided by the Framingham Heart Study. Enter your sex, age, systolic blood pressure, body mass index and a couple of health questions, and it instantly calculates your heart’s age.

If your heart age is younger than your actual age, well done: You have a lower future risk for heart disease or stroke.

It is worth noting that if you are an athlete or carry more lean muscle on your frame, the Framingham Heart Study’s online heart health calculator may present a problem. The body mass index does not account for non-average muscle density, muscular size or frame size. In this case it’s better to find out your overall body fat percentage.

A research paper in the American Journal of Clinical Nutrition in 2000 found that men between 20 and 40 years old should have a body fat range between 8 and 19 percent. For women in this same age group, 21 to 33 percent is considered healthy. Those over the age of 40 may generally climb up somewhat past their respective healthy range.

A good body fat scale can give you an idea where you stand with body fat, and if it’s within a healthy range, chances are your heart age is also good.

Make Your Heart Younger!

Whatever your heart’s “age,” consider taking steps to improve your heart health. These can actually reverse the ravages of injurious living on your heart.

The first is to eat a healthy, nutrient-dense diet with plenty of vegetables and fruits, healthy fats, beans, lentils and whole grains, while reducing your consumption of refined foods, sugars, unhealthy fats and excessive grain. Emphasize whole foods and avoid the processed variety.

Second, start moving more. A study published in “Evidence-Based Medicine” in 2014 suggests vigorous exercise is more effective at improving aerobic capacity than moderate-intensity exercise. If you can’t do that, don’t despair. You can still go to the gym, pop in an exercise video at home, or just go walking daily to get your heart in shape. You’ll start feeling better in as little as two weeks.

No one is immune to heart disease, but making some key changes can make a dramatic difference. According to researchers at the University of Indiana, adopting a healthier lifestyle can lower your risk for heart disease and stroke by up to 90 percent.

So even though you can’t rewind your chronological age, you can reduce your functional heart age—a fancy way of saying that you are healthier—and help your heart age gracefully.