I can do heat or humidity but not both. If it’s a little hot and a little humid, yes, otherwise, very hot, I can’t do humidity or very muggy, I can’t do heat.
The three times I’ve fainted in my life, two of those times were because I was dehydrated in the heat. It taught me a lesson – if you’re out and taxing yourself in the heat, make sure you drink.
As far as doing something stressful in heat, I’d say 75 would be the max before I would say “not today” unless it was something I couldn’t avoid doing.
I wear sunscreen every day, on my face, neck and chest. I think when people are covered with spots it’s not too attractive. When people express surprise when they find out my age, I tell them “I wear sunscreen every day.”