A book I read 'spark' by John J Ratey, discussed this in a few chapters. Cardio/Running at 70% maximum heart rate lead to brain plasticity and even allowing new synapses to make connections and grow. However, he did argue an exercise that also required concentration e.g dancing, basketball, skateboarding would have better results.
It's absolutely crazy, that we misunderstand how our brains are intended to work in the old world. Our brains are for movement, the ability to think, plan and utilize tools appears to have been a happy accident that allowed our ancestor an advantage in survival.
I like trail running. It combines cardio with balance and problem solving (where do you place your feet, dodging obstacles, recovering from stumbles, very dynamic compared to running on a road or treadmill).
I strongly believe that trail running is much less prone to cause repetitive stress injuries, I see so many people pound thousands of kilometres on pavement and then wonder why their knees give out at 45.
On the other side I know people getting injured when trail running, but it always seems to be acute (like scraping a knee or spraining an ankle) and they are back at it within a week or two.
Finally, at a pseudoscience level I believe that we as humans evolved to run over uneven semi-soft ground and therefore trail running is one of the most natural movements.
sophisticated coordination and balance are the most effectful brain stimulation i know, it also makes you develop a different understanding of space and time which makes you calmer (larger planning abilities maybe ?)
It's absolutely crazy, that we misunderstand how our brains are intended to work in the old world. Our brains are for movement, the ability to think, plan and utilize tools appears to have been a happy accident that allowed our ancestor an advantage in survival.
brains be braining.