This article appears in the Nov. 3, 2013 issue of The New York Times Magazine.
Trying to quantify your aerobic fitness is a daunting task. It usually requires access to an exercise-physiology lab. But researchers at the Norwegian University of Science and Technology in Trondheim have developed a remarkably low-tech means of precisely assessing aerobic fitness and estimating your “fitness age,” or how well your body functions physically, relative to how well it should work, given your age.
You will probably enjoy plugging in your numbers to calculate your purported "fitness age". Whether these determinations are accurate or not, one thing remains of interest: the parameters used to calculate fitness reliably (according to these researchers) are few. The only variables that you can actually change are your waist size and the frequency and intensity of your exercise. Thus, we must conclude (assuming that these Norwegian researchers are onto something) that exercising as vigorously and as frequently as we can is vastly important. This is noteworthy because we are often told that small amounts of exercise at lower intensities are just fine. I don't think that any of us who work out hard would agree... and this fitness calculator doesn't either. No one would suggest that you exceed your capabilities or push yourself to the point of danger, but building toward the most vigorous exercise you can do rather than simply doing a little more of this and that appears to be a good goal for fitness and longevity.