Safer than nootropics and better for your overall health, walking outperforms other mental hacking options. In fact, creative output is increased by about 60% when walking.
The Stanford study also shows that your ability to generate creative ideas through multiple possible solutions, (a.k.a. "divergent thinking") significantly accelerates while walking. And, 100% of study participants completed complex analogies while walking outdoors, compared to 50% of those seated inside.
Walking outdoors is best, but indoors offers creative benefits too. So the next time you're stuck or want to preempt a mental trough, don't make excuses: just get up and walk.