Why do you rest your wrists on your MacBook Pro while you type?
I've been typing this way since like '94 and I've yet to have any carpal tunnel issues.
Attempting to type this line with elevated wrists feels very strange and something that I couldn't do for long periods of time.
So... yeah, strap a couple pound weight to your arm, and until you bulk up, there's going to be some sagging by the end of the day.