I don't know how true this is but I always found it interesting that new makeup was developed (HD foundation) as a result of the switch towards high definition tv/cinema formats.

It's 100% true. HD changed everything from the makeup to how sets are constructed, painted and lit. Even at the level of your local newscast.

Did it also change air conditioning? I have been on sets thrice in my life, and everytime it has been uncomfortably hot.

It reminded me of a trivia: shows shot in Melbourne gave actors ice to put in their mouths - because everyone knows Australia is always hot and sunny so you can't show the steam of their breath. (when they filmed on a cold day)

In photo studio work we call the continuous (as opposed to strobe) lights hot lights for good reason. I imagine the lighting requirements for film/video isn't too much different. This was ~10 years ago though, don't know how LEDs have changed things.

LEDs help a lot. Partly because the waste less heat but also because IR spectrum is not present in LED light.

I have worked for Canal+ a long, long time ago and I have been on the set couple of times. When the studio was lit you felt hot even though there was air conditioning.

It is basically the same as meeting sunshine on a winter day with no air movement. The air is cold but the sunshine on your skin makes you feel much hotter than it really is.

There was also a resurgence in Soft F/X type filters until the Photoshop in a Can type of makeups came out.