That question can be answered at two levels. An evolutionary biologist would tell you that it is because women get evolutionary bonus points from living long enough to help bring up the grandchildren. Men, by contrast, wear themselves out competing for the right to procreate in the first place. That is probably true, but not much help to the medical profession. However, a group of researchers at John Moores University, in Liverpool, England, has just come up with a medically useful answer. It is that while 70-year-old men have the hearts of 70-year-olds, those of their female peers resemble the hearts of 20-year-olds.