I kinda thought this was true. After a good exercise session where I dont burn I def do feel a bit euphoric whether or not that is because I have pot in my system or just the effects of excersise itself is beyone me. Also I love to get a little baked when Im Mountain Biking or Skiing I find I can just sorta zone out a bit and maintain a solid pace for longer than I usually would. I do find though that aerobic activity definitely shortens the high a bit though.