The weather folks place warnings when the heat index becomes high enough to be dangerous. When the temperature, and humidity, calculate a heat index above 103 Fahrenheit, they post an advisory of a dangerous heat index. When it exceeds 124 degrees, it's considered deadly. Today, the heat index at 11:00 am is 114 degrees, yet we don't have an advisory. I don't know where the weather folks are stationed, but it isn't anywhere near where I live.
The worst heat index I was ever exposed to was working on a roof replacement in Galveston. I knew it was brutally hot, we only worked in shifts of around 15 minutes, but we were down to 4 sheets, and needed to finish the project. Rain was forecast, and the old sheets were already removed. I didn't know at the time, but after checking on the temperature related to the humidity, the index was well above 130 degrees. My brother didn't believe me when I told him. Of course, he wasn't there, and probably thought I was exaggerating.
That afternoon, while going to a meeting with a steel detailer, the cold air-conditioning in my truck started the heat cramps. They started in my legs and continued until they were in my back muscles. Unable to continue further, I bailed from the freeway, found a dollar store, bought a jar of dill pickles, and gulped down half the juice in the parking lot. Within minutes, the cramps subsided and I could continue. Even though I had been taking heat supplements, and drinking lots of water with Gatorade, it didn't make a huge difference. We were working in an environment not suitable for heavy exercise, and paid the price.