Interesting story. I have to keep that in mind.
Although, it’s not just about your fitness level. A lot depends on one’s cardio-vascular and thermo-regulatory system.
I always train and test it, running over-dressed during winter, summer, heat, rain. I always get soaking wet.
Whenever we go anywhere out, I’m always the one sitting or standing in the sun, ‘hardening’ myself.
And I believe that I can take the heat much better. But I can never be too certain.