i've heard of this before. its pretty dumb
the body doesn't want sugar post workout, it wants to recover from the stress you just put it through. by drinking this you are only stressing it out more. best thing to drink post workout? sip some water if you must. i wouldn't even eat anything until your HR drops back down.
i was once told by a dumb meathead that you must drink a protein shake post workout 'right away'. dumb comments like that are by people who simply do not understand how the body works. your body needs REST post workout, not more stress