A lot of times exercise can be mindless. We just keep running or pedaling or pushing or rowing, only tuning in when something starts to ache or complain. After all, the treadmill never goes anywhere, the pool water is always the same color, and gym ceilings are not known for their intricate frescoes. That kind of mindlessness can be good, working to still the constant wheeling of our brains.
However, paying attention has benefits. We learn where our bodies are in space (“proprioception” for you word nerds playing along) when we think about the movements we make. We discover which muscles are working. We can even figure out how to mitigate some of those aches with better form.
Change can be difficult, but paying attention makes it easier.