We had a heat wave last week that was four or five days of "please kill me". It was in the 90s - and it went there from a low temp without creeping up slowly, which makes it hard to acclimate to the sudden heat. And before you say it, there really wasn't that much humidity - a couple of days got to maybe 50+% humidity, but that is still low. (Usually it is in the low 80s; ugh.)
I usually don't mind the heat, but this time it was brutal. I had a couple of calls on Saturday and Sunday, and Sunday afternoon my Lt. said to go home because I didn't look good. He was right, I didn't. I also didn't feel good - and I would have to say it was likely heat exhaustion. I did drink water and did not spend time in the sun, but I was out of it and exhausted - but I'd gotten sleep. When I came home that Sunday, I downed a whole bottle of cold water (I normally drink it at room temperature) and took a two-hour nap. Not typical for me but I felt right after that.
Monday (Memorial Day), Tuesday and Wednesday were hot as well, but I wasn't in bad shape for them. Memorial Day was hot and I was in my dress whites, but even so, I had my ever-present bottle of water and stuck to the shade, and when the parade was about to start I got a ride back to our place in the line of march.
Tuesday and Wednesday I never made it to my hammock due to the family situation, and then it was gorgeous Thursday and Friday (although it was almost cold after the high temps of the previous days. My blood must have thinned enough that I did not have a problem with the heat anymore, and Friday I was actually chilled in my hammock!