Exercise and being over tiered??

I was told by a Chinese Medicine doctor that they believe that sweat is connected with the heart and that those with a weaker heart will not produce as much sweat. I never was a big sweater but when I got going on the elliptical pre-op I would soak up the top of my shirts pretty good. Now I can run for 15-20 minutes and although I'll get some sweat on my head and stuff, by the time I hit the lockers my shirt is barely damp.

Lately I've been watching my heart rate and things have been picking up with my heart and circulation.

For the last couple of months I have hardly been sweating at all, despite doing the same workouts. I mentioned this to a friend and what he said makes sense.
I AM DEHYDRATED!
My body is holding onto all the water it can. I know I'm not drinking nearly enough, and this just proves it.