Just a few weeks' worth of light meditation can change the structure of your brain, seemingly for the better. Thirty minutes a day can actually increase people's capacity for learning while shrinking the parts of the brain responsible for stress.
Researchers at Massachusetts General Hospital asked their sixteen study participants to take part in an eight-week meditation program centered on building non-judgmental recognition of one's own feelings and sensations. The participants only had to meditate for thirty minutes a day.
After the program was completed, the researchers imaged the participants' brains. The gray-matter in the hippocampus had consistently increased, which suggests an increase in their capacity for learning and memory building. Meanwhile, the density of the amygdala had actually decreased, specifically in the areas governing anxiety and stress. However, there wasn't any apparent change in the insula, the part of the brain in charge of self-awareness. That seems like an obvious part of the brain for meditation to affect, but the researchers suspect more long-term meditation would be required to alter its structure.
Indeed, it's important to keep in mind just how little the participants were really asked to do. It wasn't as though they were locked away in a yoga prison or anything similarly strenuous - rather, they just did a total of 28 hours of meditation spread out over eight weeks, and yet this was enough to alter the structure of their brain. It's a powerful reminder that our brains are incredibly malleable and structurally responsive to even modest changes in our lifestyle.
[Scientific American; click the link to check out a podcast that discusses these findings in further detail.]