Does the U.S. have the highest health standards when applying for a flight medical? Thanks

No, the US is very liberal. The Europeans and Asians have the highest standards. Some third world countries just a require a US or European medical, or no medical at all...if you are alive when you report for duty, they figure the odds are good that you will still be alive when you land.

The US is mainly your medical history. Was in Europe years ago and needed a medical. Mien Deutsch wasn't up to explaining to the nurse that I only need the FAA medical and not the LBA. They do the EKG on a treadmill, hearing test in sound proof booth, etc. The doctor's English was better than mine and he tossed the LBA paperwork but said after the office visit, a German applicant would head off to a hospital to have blood drawn and it would take a few days to get the lab work done. No walk in and walk out with your new medical.

I'm curious, which countries don't require any medical? Thanks

Some African countries.