You'll get dehydrated faster at high altitude, but even drinking a lot will not help you adjust to high altitude. It will just be worse if you don't drink a lot.

It's the lack of oxygen that your body needs to adjust to. I live at 8000ft, and every spring when I go back up to 11,000ft I need time to adjust to it.

You'll never be as strong, or have as much energy at high altitude as you will at lower altitude no matter how much you adjust to it. So, it's important to be in the best shape you can. Just being in ok shape at low altitude won't work. You'll be laying camp while everybody else is out hunting.