[lm28469]

> I doubt it has a big impact on our health and longevity

It definitely has an impact on your quality of life and helps you attain your genetic potential. If you're body is prone to cancer or alzheimer you will still get them, but until then you'll be in top physical condition.

When you're 40 and start packing up weight, can't run nor climb 3 flights of stairs without panting, can't lift your kids, can't help your friends move to a new flat, &c. fast forward 20 years and you can't get out of bed without pain, walking is a chore, stairs are your nemesis, your back pain is a constant reminder of your unwillingness to exercise.

> translates into about 2 years of productive life.

I don't think making a distinction between "productivity time" and "staying in shape time" is a good thing to do. You better shave off time by working part time than shave off time by skipping physical exercise. Life doesn't have to be all about productivity.