alt Hacker NewsThe amount of time in the exercise advice keep getting shorter and shorter. The common advice when I was younger, in the USA, was an hour of exercise. Couldn't get enough people to do it. Then it was 30 minutes. Still couldn't get people to do it. Now the advice has been 15 minutes a day for a while, and we'll still not be able to get people to do it.
The environment and culture needs to be structured such that people get the exercise they need "naturally". The vast majority aren't going to go out of their way for it.
That's a big part of why zoning is so dangerous. In most of the western world (Europe too on average), we pushed down population density so much that your typical destinations are much less likely to be within walking distance, so you don't walk.