Heart disease is the No. 1 killer of U.S. men and women, accounting for 40% of all U.S. deaths. That's more than all forms of cancer combined.
Why is heart disease so deadly? One reason is that many people are slow to seek help when symptoms arise. Yes, someone gripped by sudden chest pain probably knows to call 911. But heart symptoms aren't always intense or obvious, and they vary from person to person and according to gender.