Many people have good intentions with respect to exercise, but intentions carry through to actual exercise at about the level predicted by chance, according to a dispiriting new study in BJSM. Intentions simply don't translate into exercise, and many things conspire to make that worse, like the evolved human tendency to effort minimization.
More broadly, this is a persistent problem, one that is made worse by the many tricks and shortcuts that become popular. For example, HIIT (high intensity interval training) can work, and takes less time than other forms of aerobic exercise, but most people can't do HIIT at the intensity required, or become injured when they do.
Similarly, the "minimum exercise dose" literature, while well intentioned, mostly drives home the efficiency case, when most people would be better off being "slopping" about their exercise, not efficient, doing well more than the minimum.
The key is developing sloppy habits where you regularly do more than the minimum, not just gamifying things, or doing the minimum effort required—or none at all, obviously.
Related reading:
The intention-behaviour gap in physical activity https://bjsm.bmj.com/content/57/19/1265
