So how do you know if so-called longevity risk will cause you financial problems or if your heirs may be asked to foot the bill if you run out of money?

FORBES: Managing Your "Tail-End" Risk - Part 1: The Risk that You May Outlive Your Assets

Finally, and most important, recent studies have shown convincing evidence that cardio-respiratory fitness is a much stronger predictor of longevity and reduced risk of cardiovascular mortality and all-cause mortality than BMI.

FORBES: How Useful Is Body Mass Index In Predicting Long-Term Health?