Heart disease is the leading cause of death in the U.S. for both men and women.

And nearly half of adults over age 40 may have hidden heart conditions that can increase their risk for a heart attack, according to a University of Copenhagen study.

Chauncey Crandall, M.D., the New York Times bestselling author of "The Simple Heart Cure: The 90-Day Program to Stop and Reverse Heart Disease” and director of preventive medicine at the Palm Beach Cardiovascular Clinic in Florida says that while everyone knows that smoking can lead to heart attack, there are other important, less obvious risks to be aware of.

In addition to diabetes, high blood pressure and high cholesterol, some less obvious heart risk factors are stress, lupus, arthritis, sleep apnea and low hormone levels.

Dr. Crandall points to inflammation as the silent heart disease culprit.

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“People that have arthritis, lupus, even other inflammatory conditions, such as COVID ─ these are silent irritants of inflammation that set off heart disease. And it is just coming to light right now,” Crandall tells Newsline.

“And stress,” continues Crandall. Stress can also lead to heart-damaging inflammation.

Crandall says it is hard to avoid stress right now with the events happening in the world, but we need to lower our stress levels. “We need to remove ourselves from stress,” explains Crandall.

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To lower stress, Crandall recommends trying to walk an hour a day. And pray, which he practices daily and says can also help lower stress.

In addition, Crandall recommends eating a Mediterranean diet, getting proper sleep and keeping weight down to a healthy level.

“These are really the five key steps we can do today that will give you a long life, and better health,” says Crandall.