Some afternoons do not need a complicated intervention. You have been staring at the same paragraph, the room feels stale and every task seems to have acquired extra weight.
Put on a song you enjoy and use it as a small change of scene. You might move comfortably around the room, tidy a clear surface or simply stand away from the desk if that suits you. Keep the floor clear and the volume considerate.
The song is a boundary, not a challenge to squeeze in a certain number of movements. Choose an activity you already know is suitable for you, and stop if it causes discomfort. There is no prescribed routine to perform correctly.
When the music ends, decide what comes next. Perhaps you return to the task, make a drink or take a proper break. The useful part is interrupting an unhelpful stretch of sitting and staring long enough to choose the next step consciously.
Everyday Motion
Ideas to make a little room in your day.

