As a med-school dropout, in his early 40s (left medicine two decades ago), I cannot even imagine having enough energy to even apply for medical school. At least in the United Hates of America, this is my jaded perspective.
I became an electrician, instead, with stints IBEW and self-employed residential. Lots of money-making opportunities, but lots of unlicensed competition from handymen that "know just enough to be dangerous" — most customers only care if the light turns on, not that it's long-term safe.
I'm actually attempting to get into officework, somewhere. I can't do another twenty years of physical construction, whether in houses or factories.
>Are you self-employed now?
Yes, but I choose not to work regularly.
Fortunately, I have enough savings to not be too worried — presuming the economy picks up within the next few years (I can outlast this presidency, doing nothing).
When I was 45, I did briefly consider making the switch