My body sent me its first wake-up call more than a year ago, on an evening I'll never forget. One night last June, I—someone who has had every heart test known to womankind and has been repeatedly reassured that I have no blockages—awoke with my heart palpitating so intensely that it felt like it was going to beat right out of my chest. Pound! Pound! Pound! For the first time in my life, I thought I was about to die.

A doctor's visit confirmed what I'd already been told: I don't have heart disease. Over the next six months, my attempts to figure out what I did have led me to four more doctors—and not one could explain the palpitations. Then one morning when I was out running, I mentioned the palpitations to my trainer, Bob Greene.

"I think it's the big M," he said.

"The big M what?" I shot back.

"I think it's menopause," he said.

I stopped and stared at him. "Of course it's not menopause!" I said. "I'm still having my periods. Regular as rain!"

Like nearly every other woman in America, I believed that menopause would hit when my periods ended—that I'd suddenly wake up one day during my fifties in a fit of hot flashing. Yet over the next few days, Bob's words stayed with me: Could he be right? Of the five doctors I'd visited, two were female. Neither had asked whether I, then age 47, might be nearing one of the major markers of a woman's life. I finally put the question directly to my fifth doctor, a heart specialist: Could I be entering menopause? "Well, if it's menopause, ma'am," he said, chuckling, "you're definitely in the wrong place! I don't know a thing about that."

What happened next can only be called a miracle. A few days later, I was walking around the Harpo offices when I noticed a book called The Wisdom of Menopause. I opened it right to page 456, where I saw a subtitle that seemed to shout directly at me: "Palpitations: Your Heart's Wake-Up Call." I spotted a woman's story that sounded exactly like my own: "I am a 48-year-old female with no major health problems." Check. "My periods are still fairly regular." Check. "About a month ago...I started experiencing heart irregularities. I felt like my heart was skipping a beat and was going to beat out of my chest!" Double check. Then I saw the line that clarified everything: "There's no question that heart palpitations at menopause are related to changing hormones."

(Before you declare yourself perimenopausal—peri means near or around—hear this: A racing heart could be a symptom of a life-threatening condition, like heart disease. If you experience irregular heart rhythm, please get to a doctor right away.)