This post is half in jest but there is a grain of truth to it.  As I was lugging a large Olivetti-Underwood 21 in case and sensed how heavy it felt, I realized that I do this a lot and that I repeat this process often.  Maybe at 75, I tend to feel it more.  During Covid, it was probably the only exercise I got.  What most people don’t realize is that collecting typewriters is a more physical endeavor as typewriters do weigh a bit…mine weigh from 10lbs to 27lbs.  I have 22 typewriters, all with cases, in my house and I am constantly schlepping them from one room to another and going up and down the stairs to the basement where most are stored.  I do this in my attempt to rotate them to put all of them in rotation so that they get used and remain nimble.   There are a few days where I rotate two or three.  That leads to a lot of lifting. climbing and walking.  Of course, typing on them is exercise for my two fingers (yes, limited typing skills).  When I was younger, I prepared for a backpacking trip by putting a large typewriter in my backpack to practice for a Boy Scouts excursion.
In summary, you can avoid Gym fees and get in shape by collecting typewriters.  As for mental exercises, nothing beats tweaking and fixing a malfunctioning typewriter, better than doing Sudoku or crossword puzzles.  That’s how I keep mentally sharp.