You are used to multitasking at work and home, so why not apply it at the gym as well?
If you are comfortable walking at a brisk pace on the treadmill, make it more challenging by combining it with some simple dumbbell exercises.
While keeping your balance on the treadmill, do sets of shoulder presses, biceps curls, triceps extensions, standing triceps and kickbacks one after another as you walk. Only perform these exercises if you can keep proper form and don’t run the risk of injuring yourself.
If you are not familiar with dumbbell exercises, ask your physiotherapist for help or to suggest alternative exercises that would suit your fitness levels.