> The benefits of exercise might not be immediate, says Singh, but they should show up within weeks or months. Beyond that, the longer people engaged in exercis

> The benefits of exercise might not be immediate, says Singh, but they should show up within weeks or months. Beyond that, the longer people engaged in exercise, the less beneficial it became for their mental health. This may be because they were sticking to the program less, due to waning motivation or, perhaps, injury. It could also be because the exercise itself began to feel less novel and more repetitive. Not mentioned here that I think should be considered is how much of the benefit was just due to _novelty_. If the effect wears off over time then at least part of it may be going out and doing something different.