Each hour you spend running adds seven hours to your life.

Have we got your attention now?

You always knew that running was good for your heart and health, but we bet you have never seen its benefit quantified exactly like that before. Looked at another way, runners live three years longer than non-runners.

All the new detail is the result of a review of research led by Dr. Duck-chul Lee from Iowa State University. Lee and his team re-examined data collected three years ago in conjunction with more current research. The scientists determined that running drops a person’s risk of premature death by 25 to 40 percent.

Even after allowing for smoking, drinking and health problems like hypertension and obesity, the scientists determined that the longevity benefits of running could still be anticipated. (So don't eschew running even if you do like to eat heavy or enjoy your cigars – you'll still benefit.) The data clearly suggest that if you have time for only one activity at the gym, make it the treadmill.

But before you strap yourself into a giant hamster wheel in an attempt to turn back time, note that there is an optimal amount of running your body needs, beyond which the benefits bell curve off. This was determined in a previous study in Copenhagen, which examined healthy joggers and non-joggers for over a decade. There the data indicated the most favorable running regimen for reducing cardiovascular mortality was found to be six miles per week, including three running days per week, and a pace of seven miles per hour. In fact, the Copenhagen City Heart findings showed that strenuous joggers had a mortality rate that was not statistically different from that of the sedentary group. Improvements in life expectancy reach their peak – an extra three years of life – at about four hours of running per week.

The research was published in Progress in Cardiovascular Diseases.