Is Pilates an exercise?
Pilates is most definitely an exercise and when performed correctly it's very challenging!
As an exercise, it counts as a muscle-strengthening workout. Plus, you're able to work the whole body through Pilates. It challenges your lower and upper body and demands core strength.
Is 20 minutes of Pilates per day enough?
I believe to do at least one hour per week with an instructor will always have the benefit of being corrected as well as learning further movements once you are ready for it.
To do an extra 20 minutes or even 10 minutes per day to keep you supple and loosened up , is always a very good idea. I am always happy to give you a little program which is suitable for you.