Hi Richard, sounds like you have a lot of experience with exercise, congratulations on the half marathons!

As far as hydration goes I find what works for me is 1/2 to 1/4 strength Gatorade or similar electrolyte powder. Full strength has so much sugar that it seems to just go right through me, but you do need some sugar for optimal absorption.

I do find that wearing a hydration pack makes the biggest difference for me because water is always there. Especially for things like backpacking when you're consistently moving. I'm currently in the Philippines scuba diving, and just drinking a lot of water is keeping me hydrated.

As far as weight training goes, I try to be careful with twisting exercises as I have developed a small parastomal hernia. I'm not a big fan of wearing a hernia belt, but a lot of people find that it gives them security, and it is possible that it helps prevent parstomal hernias.