Which kind of heat?
It might "biologically hold up" for places with dry heat because your body isn't sweating it out (so you actually need to be protected from the heat, or indulge in activities that make you sweat).
But in places that are humid and make you perspire by merely standing outside, less is more, as the sweat needs more exposed skin to shed the heat. If you've ever lived in a place with humid heat, you know for a fact that just standing outside without even doing anything will get your clothes soaked in sweat in minutes. Your thick and long sleeved clothes drenched in sweat are only going to stick to your skin intensely reducing its ability to sweat and giving you skin problems in the long run.