My 57 year old husband has diabetes and now uses insulin. He works in a steel mill handling very hot steel after it comes out of the molds. The ambient temperature on the steel runs between 900 to 1000 degree. My husband works around them. He once used an over thermometer to measure the air temperature in the area he works in and it pegged at the highest point. His blood sugar has been ranging high despite watching his diet carefully and taking his insulin religiously. I have noticed that his feet are showing heavy blistering from the heat which I suspect is due to his being diabetic. My question is: Is he taking a risk working under these extreme high heat conditions. I am very concerned for his continued health.
Certainly heat poses a problem for people with diabetes. So when people say heat effects people with diabetes, the main problem is that stress raises the blood sugar and the body is more prone to being dehydrated. If your husband has been working at the steel mill for some time, I'm sure he is hydrating, but he may need to look for a trend and if he is consistently high at the mill, it could be a stress hormone that raises his blood sugar. He should talk with his doctor about changing the dose of insulin to accommodate the heat in the factory. Your doctor, or certified diabetes educator, is your best bet for helping manage this situation!
Here is a link to heat advisory for weather, but the same advice can be used for hot conditions of any kind! Granted much of the information pertains to type 1 diabetes, but it still applies. http://www.healthcentral.com/diabetes/news-526430-98.html
Hope this helps!