If joining paramedics at your 30s-40s, what are you most likely not able to do compared to the 20s?

I know everyone always says you are never too late to become a paramedic, but let's be realistic: it is a profession that requires physical strength and tenacity, transporting patients, long shift works.

I would love to have a realistic expectation going into the career, so honest input pls: those of us who are more matured candidates, what are the aspects of the job that we may not be in the prime for anymore? (Or am I wrong here - there are no limits?)