If in addition to your Pilates routine you do cardiovascular or aerobic workouts–like running, using an elliptical, etc. your might be interested in a January article published by The International Journal of Obesity.
They determined that high-intensity intermittent exercise (HIIE) may offer more cardiovascular and weight loss benefits than working for a prolonged period at a steady pace. Intervals have been found to be a very effective way to work out, but this study tested very short intervals (8 seconds of high intensity followed by 12 seconds of rest repeated for 20-minutes).
I tried it on the elliptical at the gym. You can’t focus on anything else because every 8 to 12 seconds you need to change what you are doing, but it didn’t feel as exhausting as longer interval training I have done. Since I find ellipticals boring, I convince myself to workout on them by allowing myself to read–an activity I love, but don’t always have time for. Interval training is not conducive to that. However, it was nice to do intervals and feel less tired while potentially getting more benefit.
This doesn’t mean you should only train with short intervals in the future, but it does give you something different to try and think about. It might be fun to adjust your workout for a literal change of pace.