I've got the same problem - almost like that efficient furnace turns itself down to "vacation" setting when I stop moving (whether from an actual commute or my morning trainer ride). I load on the clothes and everyone at work laughs at me. The only thing that works is getting up and doing a few jumping jacks or such to rev things back up. I don't think I'm the ultra-fit athlete or anything but my heartrate goes way down, body temp way down and brrrrr!! Maybe an electric blankie at work??