JACKSONVILLE, Fla. -- Drivers in downtown Jacksonville are getting a reminder today about a potentially deadly issue.

People covered in red from head to toe and holding signs are supporting National Wear Red Day.

It happens on February 1 to kick off what the American Heart Association calls American Heart Month.

One supporter says knowing your heart health can be a matter of life and death.

She thought she was perfectly healthy -- but ended up having a stroke in her mid-40's.

"I had a TIA and I ignored it. And if I had gone to the doctor, I never would have had a stroke. You have to take time out of your busy schedule to take care of yourself," said Mary Kellmanson.

This is the 10th year for the Go Red for Women campaign.

Heart disease is the number one killer of all American women, beating out every form of cancer combined.