that I cannot tolerate heat the way I used to. Yes... I can still 'cool' off much MUCH easier than get warm BUT...
When I was farming I loved those extremely hot days. Out in the middle of a field in the middle of July when it was 112°... sweating profusely. It was energizing to me. No longer. Those days are long gone even though my tolerance for hot weather remains much higher than most people I know.
Frankly people like you amaze me... that is: Those who can dress 'warmer' on cold days and have it be sufficient.
My wife and I are exact opposites.... on very cold days, inside my house, it's common for me to be in thermals AND under a blanket while lounging on the sofa and she will be in short sleeves with a fan blowing on her. I have no thermostat power in my home.