Land animals first evolved intelligence when we emerged from the cloudy, murky sea and developed the ability to see shapes (predators, prey) really far into the distance. This required the ability to understand the future and perform spatial reasoning. Not all aquatic species were exposed to such pressures (opportunities), since line of sight vision (especially traveling at speed) is limited.
We got really smart when we became endurance hunters and out-walked and out-ran our prey. Bipedal locomotion and sweating were clutch advantages for sure, but our brains became especially attuned to multi-tasking when walking and running. We could see our prey far into the distance and could plan hours in advance for how to exhaust and corner it. Especially as a group activity. This engaged spatial, temporal, collaborative, and complex reasoning.
We didn't evolve to think at a desk. We evolved to think because it greatly enhanced our hunting skills and survival fitness.
When you walk or run, you're directly engaging machinery that was fine tuned over hundreds of thousands of years.
1. It’s really easy to create a fictional narrative of what our ancestor’s activity was 50k years ago because of the lack of empirical evidence. The truth is we know only a little and guess at a lot.
2. It’s been associated with many false claims. So many fad diets, fad supplements, and fad exercise routines have made use of evolution to build a narrative of why it’s healthy. I’ve seen both carnivore and vegans use evolution to explain why their diet is correct.
3. The modern environment is just different than the pre-historical environment. We have clean drinking water, unlimited sodium, modern medicine, air conditioned and heated shelter. To me the real question is what is the healthiest decision for me, not what is the healthiest decision for someone 50k years ago.
I don't see your point? Not seeing the forest because of all the trees?
Octopussies have fun moving in weird ways, too. Also exploring, and making fun of captors!
Birds...did you know that their five feathers on the ends of their wings are the equivalent of our fingers, neurologically/network-wise? They sense the currents of the air with them.
Whatever. I think, no matter which species you are belonging to, it can be good to have these systems in more or less autonomous action, moving by themselves, while having a somewhat detached mind, soaring along, thinking about other stuff than the usual chores.
Edit: Maybe something like micro-dosing a little bit of 'Runner's high' by walking aimlessly?