I sometimes use breathe right strips.. They do work. Arm Pump is mostly caused by a buildup of lactic acid in the muscles. Increased oxygen flow will help alleviate that.
All of the working out in the world isn't going to help, if you aren't breathing right.
Also grip the bike more with your knees and less with your hands. That will help.
Stomp grip is a little more gentle on the gear and I've had better luck with griping the bike using it over grip tape. Again, loosen up your grip and learn to be comfortable with the bike moving around a lot underneath you. Riding loose=riding fast, and you'll be amazed with how much longer you can ride the faster you go. All of a sudden all of the chop turns out smooth and the bulldogging in the corners turns into a lean and a flick. Riding becomes much easier....