Here is California our pretrial heat conditioning consists of, hardboiled eggs, broccoli, jalepenos and gatorade.
And I know you'll say it's dry heat but.............preheat your oven to 450, open the door and place your face in it.
Same thing!
Actually we prehydrate and use a camelback, lots of water and bananas. Take breaks inbetween loops in the shade.
With low humidity (25-15%) you don't sweat a whole lot so you have to be careful.
Not alot of shade in the desert.