You could try wearing a dust mask while going through your cardio, will help simulate reduced O2 levels.
Even before you get there, start a hydration regiment. It seems odd but the more you can stay ahead on hydration at attitude, the better off you are going to be.
Another tip is to cut out, or at least way down on alcohol before and during the hunt. I know, it's a bummer but the alcohol offsets hydration and affects O2 levels in your body.
If it's an option, on your way to your hunting area, spend a night at an attitude 1000 to 2000ft below the altitude of the base camp. Try to do this especially if you are making a drastic 3000ft+ altitude change. This will help you cope with any potential altitude sickness. Give your body a little more adjustment time before the hunt starts.
I guided hunts for 17 years and saw a good many hunters having to deal with various degrees of altitude sickness (headaches, nausea, cramps, low energy). I've seen it happen to first timers and also to those who have maintain hunted before with no previous problems. It sucks!!!
DO THE HYDRATION!!!!!
Good luck on you hunt!