These comparisons are crap. You can‘t simply take one year, exercise 24/7, and get your 10 years of life. You have to fit it into life, which is much more time than it seems from claiming it‘s 1 year out of 80.
But it‘s still a good investment! :)
We use this sort of formulation everywhere. If I say I work 40 hours a week, no one is going to assume that I start work at 9am on Monday, work non-stop until 1am Wednesday, and then take the rest of the week off. If I say that people spend approximately a third of their lives sleeping, no one thinks I mean that they sleep continuously from birth until they're 30 years old, and then spend the next 60 years awake.
So it's not exactly the same. For people who have very little free time due to commute, work, children, etc. It's harder to spend half an hour of free time a day on exerciaing.
I mean I do agree with the premise that exercising is a good return (especially since the better sleep quality should be factored in) but I think the person you're replying to has a point when he says that saying it's one year of life is not really comparable
I mean, we all know of the university budding sports star types who probably invested in many hours training and trying to break into their sport professionally but not quite cutting it - and then "retiring into mediocrity" with the regular 9-5,2 hour commute, 3 kids and the diet to match. They exercise no differently to the regular Joe and suffer all the maladies the same.
That’s not what he said though. How would you demonstrate that it’s a good investment, do you have an alternative? For the purposes of calculating the ROI it’s a solid 24/7 year of accumulated exercise time. Of course you can’t do it all at once, but that wasn’t the claim. And sure you have to fit it into your life and sure there’s a little extra time go to and from your activities, but the ratio of exercise to time is roughly 1/80. If you exercise 45 minutes a day 3 times a week: 135 minutes out of 10080 minutes ~= 1/80. He said 4 times/week, so maybe he should have said 1.3/80, but that doesn’t actually change the point. Accounting for sleep and more exercise and lots and lots of travel+shower time, maybe it’s even as high as 1/20… still a great investment.