[Gerd Kempermann and his colleagues at the Center for Regenerative Therapies Dresden in Germany] found an additive effect: exercise alone was good for the hippocampus, but combining physical activity with cognitive demands in a stimulating environment was even better, leading to even more new neurons. 

Link: Why Your Brain Needs Exercise

I wonder how games like Beat Saber fare for helping neuron-formation. It seems like it would be right in the intersection of cardio and thinking.