These areas of the southwest can be very hard on the body, and deceptive so that a person doesn't realize they are in trouble until it is well past time to do something. In the heat and dryness your body can be sweating profusely, yet evaporating so fast that you think it is not that hot. A person can lose a lot of water thinking that they are not sweating at all and that everything is ok. Then the symptoms of dehydration and heat stroke take over quickly.
Just not going there, I am a city girl and will give the wilderness a pass at all times!
Two of us from the rainforest that is Pennsylvania were walking around the Desert Museum in Tucson. Neither of us were carrying water. After about a half hour the two of us looked at each other at the same time. We had never experienced our throats go totally dry and feel like they were closing up before. It was a short walk to a concession but the rest of my time in Arizona I always had water nearby.