How will people work in 165 to 170 degrees eventually?

Well. There is the short time work of ice in your hat because your brain is the first to go at 165 to 170 degrees Fahrenheit. However, in the long run a refrigerated suit likely would be best. So, the average person would not be able to afford something like this to prevent them from passing out in the heat.

How most cultures deal with this is they work at night instead of during the day at high temperatures. When my father and I were working near Gila Bend in Arizona for about a week or more we usually chose to work between the hours of 3 am when it might be 102 down to 100 and before 9am or 10am in the morning. Because it is just too hot in the desert from about 10am to noon until about midnight at night when it is 120 degrees or more out high temperature. So, most people choose to work during the coolest hours when the sun is not out or just coming up to compensate for this kind of heat to be able to actually survive it.