F/As go through annual recurrent training. During recurrent, medical procudres are reviewed and CPR proficiency must be demonstrated. Evacuation drills are performed, and the F/A must be able to perform the drill, including the operation of exits for every exit on every aircraft they're qualified on. If a F/A can not physically operate the exit, they can no longer be a F/A. I believe AAs oldest F/A was asked to retire after she could no longer operate the exit on the 727 during her recurrent training. I don't think a big deal was made of it, she retired, not officially fired. But, a F/A must demonstrate that they can operate the exits. Also during recurrent is a written test, that covers basic policies and procuedres, and a security segment.
There is no offical FAA medical like there is for pilots. Personally, I think there should be.