I think working out is to 'scientific' these days & the healthiest people in the world with as little mental/physical health issues until
death is from a long time ago.
For me, I work out to keep my overall body in shape. You won't catch me going to the gym to do legs one day, and chest another day,
and try to become some massive guy.
I try to eat solid foods, no sugar, barely any grain, no processed, etc.
You'll catch me doing a couple hundred different dumb bell reps, squats, situps, pushups, and going for a walk almost daily.
Sometimes I do 30 curls, 20 butterflies, some shoulder raises, and some triceps, without even putting the weights down. It'll be a
100-150 rep set all at once, pouring sweat, etc. I find this kind of endurance working out to be more beneficial for me than any sort
of scheduled shit.