I have usually only worked with companies that have a non energizied policy, and mostly in new construction. Only once did a company have a required dress code and that was for color only,
Northern rednecks! I've never heard of any local EC company stressing or requiring the requirements of what's required by NFPA. POCO is always long sleeves.
I can't wear ring collar tee shirts, I feel like I'm choking.
I wear (henley-shirts) three button short sleeves, three button down long sleeves for out in the weather work.
Full button down shirts with collar, or V-necks.
You might try wetting your wrist (where one would take ones pulse), this is refreshing and a "conduit" that one can use to dissipate heat in your arms. This is also mentioned in First-Aid training, to damp cloth the same area for heat stroke victims...
Good luck stay safe...
If you are even thirsty, you are two quarts low.