I don’t think it really matters all that much. Doing anything is better than doing nothing.

Just do any exercise that’s convenient and don’t overthink the details. Make it as easy as possible to get up and do. The more complicated you make it, the less you’ll actually do it.

I tried sprinting on the treadmill and found that too aerobic, and I would sweat at my desk afterwards, and I tried bicep curls and found that not aerobic enough and really just an arm workout.