Interesting stuff. I'm finding the same, but I excersise for 35 minutes at night, an hour before bed--and I'm not finding sleep to be a problem *until* I start cutting back on calories. Then I don't seem to unwind right so I can fall asleep properly. Maybe it's because I tend to have a high-calorie snack before bed, and once I settle into an exersise routine (as opposed to my normal sedentary routine), I find my appetite to be diminished for some odd reason.