My yoga teacher insists that inversion poses have youth-preserving and brain-enhancing powers. I can't say for sure, but logic dictates that they are very unlikely. If blood rushing to my head really does improve my cognitive abilities, I would have gained several IQ points by now, having been inverting myself into wall-supported handstands nearly every single night.
I don't remember the exact number of years I've been doing yoga - granted, never intensely - but it must be at least 6 or 7. I remember I never managed to go into a headstand away from the assuring protection of a wall for the first 4 years or so. Yoga was not a series of challenging poses to master; it was my weekly physical activity, amounting (almost) to exercise that I fondly hoped would help keep my weight in check (yikes!). I was too comfortable and complacent in the class that was just me and my friend, and never had the motivation to take that leap. It came in form of a reprimand-like observation by a rock-climbing yogi who I met when I first took up climbing. Long story short, he was rather aghast that after 4 years of yoga, I hadn't learned how to do the handstand.
It took a while, a lot of courage and several falls to stand on my head (and elbows) in the middle of the room. The tripod quickly followed. I found that once I figured the key to stabilizing my body while being upside down, everything just works.
Handstands, however, are still a long way off. While I've been able to hold myself in position against the wall for a some time (years, in fact), I haven't been able to grasp the mental and physical key configurations to break away. That is why I hop up against the wall every night. If anything would work, it would be ceaseless, relentless determination.
Yoga is no longer just another physical activity amounting to exercise. It is so much more to me now, although I'm not (yet) at the level where I take an interest in the philosophical and spiritual aspects. Conquering the handstand is my current goal. Next, perhaps the Scorpion.