Hm.
A bit of prep and understanding the body chemistry of exertion in a hot environment is all it takes to be safe.
I went on many hundreds---probably over a thousand---rock-climbing hikes in remote Arizona with temps 110 and up, and also (by chance) on both of Arizona's all-time high record days (120 and 122). I also raced cross country motorcycles and raced motocross. Never once had a heat-related issue.
The main "gotcha" is people don't realize that water alone isn't enough, hydration-wise. Sweat that is replenished by water only creates a mineral imbalance which jacks up your body's "electrical system". Nerves stop working right, and nerves control muscles... when they start going haywire---the imbalance sneaks up on you, too---you are definitely in trouble. (By the time you realize something's happening, getting "right" again takes HOURS)
Meaning drink something like Gatorade, NOT plain water, when out and about in desert heat. Wear a hat, a loose(ish) long-sleeved shirt, keep drinking whether you think you need to or not, and otherwise enjoy yourself.
It's 100% common sense except for the minerals/nerve conduction thing.