I'm hoping I'll get some info on this by someone who knows - I certainly don't! I'm proud to say that I've steadily increased my time on the elliptical trainer over the past month from 20 minutes to 75 minutes per single session. But I've recently begun to split my session in two, taking 15-30 minutes between times. What I find is that with this sort of arrangement, I work out longer (2 sessions of 45 minutes each!) and harder (from about 500 to more than 700 calories burned). I think this is a good thing but I do wonder if there is a negative aspect to it - fr'instance, does it mean that I'm disrupting the time I spend in the 'cardio' zone? Thoughts appreciated!