PB- it's different every day. If I do a class they are always 1 hour. Days when I just do treadmill or elliptical I do 30 min, usually burning 250-300 cals. I do pilates for my abs! I have had strong abs but they were just sort of hidden cause I wasnt doing much cardio. I still have a little bit to go to goal but at this rate it's gonna be no time at all!