I don't know if it's mad coincidence or if I just have a very strange circumstance, but when I've done a cardio exercise session and weigh myself after, I weigh up to a pound and a half less than the morning before I'd done it. Is this even possible?!

I do the same thing. Not sure why...

my guess is the rapid weight loss is fluid loss. try more hydrating before/during/after your cardio.

That does not happen to me, but it is probably a lack of drinking enough water before a work out, on my part.

Water weight, you are sweating and losing it that way

Sure some of it's fat but most is water, make sure you are hydrating

uh, its water/glycogen, and it comes right back later in the day. I lose up to 5-6 pounds on a run (long)......

after a run (about 15minutes) i lose about a pound but then i gain it back plus some for unknown reasons. i was told by my trainer not to weigh myself after a workout because its wont be completely accurate.