Apprentice electricians need to be in good shape. You'll be out on job sites, in buildings under construction, climbing ladders, pulling wire (long runs of wire are heavy, etc. possibly in cold or windy or rainy weather, etc.
This is true of most trades, except maybe machinist. That is what I'd look into, personally. If you're a programmer, you can still continue that by learning CNC programming.
I honestly don't know how easy it is to get into trade work in your 40s with no experience though. I think most people in those jobs start straight out of high school.
I enjoy some machinist porn, especially youtube.com/mymechanics. That guy is amazing. I'd be curious to know how he got to where he is, because that gear and those skills didn't come to him overnight.
This is true of most trades, except maybe machinist. That is what I'd look into, personally. If you're a programmer, you can still continue that by learning CNC programming.
I honestly don't know how easy it is to get into trade work in your 40s with no experience though. I think most people in those jobs start straight out of high school.