Could flat abs be the secret to a successful retirement? It's not as far-fetched as it sounds.

A lack of abdominal, or core, strength correlates to higher cortisol levels and job stress that carries into retirement, researchers say. It can cut careers short and boost health expenses as it leads to a host of heart and other diseases, all of which affects our retirement bottom lines.

The research, being performed by an emeritus professor at the University of Arkansas, marks just one unusual way that chronic stress and other health issues can stick with us long after the job ends.