How does one manage exercise, if at all, with this condition, in the heat?

So, I am trying to be on a weight loss journey as I’m overweight and I want to lose 120 pounds. My biggest issue right now is exercising. My POTs can slightly handle me exercising, it has to be a slow walk around the neighborhood or a slow walk on the treadmill, cannot be anything more. I can do some other stuff like lifting weights just fine too but any intense stuff and my body doesn’t like it due to my POTs.

I am mainly wondering though how does one exercise in this heat… I want to start walking right now but it’s been in the low 90s to upper 80s all week and will be next week too. Humid as heck as well. I don’t know how to exercise in that kinda heat without feeling really sick. Does anyone have any tips?