You probably know yoga is good for you, but you may not know how good. In a recently published study, researchers reviewed 11 different studies that compared subjects who practiced yoga with those who didn't, to see what effect doing yoga might have on people's brains. The results suggest that several brain areas benefit from yoga, including the areas that control decision-making and planning, those that control emotions, and those that control memory.

A team of researchers led by professor Neha Gothe of the University of Illinois and professor Jessica Damoiseaux from Wayne State university studied the studies. All the studies used brain scanning techniques such as MRIs or fMRIs to examine participants' brains. Six of the studies compared people who regularly practiced Hatha yoga (the most commonly practiced form in the United States) with people who didn't. But in the other five studies, all the participants started out as non-yogis, and then some began practicing once or twice a week for 10 to 24 weeks. Even that amount of yoga was enough to make some measurable differences to participants' brain function

What were those differences? To begin with, a measurably larger hippocampus. That's very important because the hippocampus helps in memory processing and it gets smaller as you get older. " "It is also the structure that is first affected in dementia and Alzheimer's disease," Gothe notes. 

Researchers also found that the prefrontal cortex and brain networks appeared larger in those who practiced yoga. The prefrontal cortex "is essential to planning, decision-making, multitasking, thinking about your options and picking the right option," according to Damoiseaux -- in other words, yoga makes you a better decision-maker. If, like me, you often find yourself thinking through your most pressing problems while practicing yoga, this may not come as any surprise.

The amygdala and cingulate cortex are also larger in yoga practitioners, and both these brain areas contribute to emotional regulation and learning, as well as memory. In a previous study, Gothe found that practicing yoga reduced the release of cortisol, commonly called the "stress hormone," even after only eight weeks of regular practice. It all adds up to this: Yoga helps you manage your emotions much better.

Why is that? For one thing, yoga forces you to focus on deep and steady breathing, and often on making your exhalations longer than your inhalations. That simple technique communicates calm to your body, by automatically slowing your heart rate.

Quieting the fluctuations of the mind.

More to the point, calming your emotions is exactly what yoga was originally designed to do. We know this because we still have one of the ancient texts that explained yoga more than 2,000 years ago. That text, called the Yoga Sutras of Patanjali (Patanjali was the person who wrote them down) is basically a bible of yoga. Each of the sutras is a short aphorism about the practice of yoga, and the second one, in Sanskrit, says "Yogas citta vrtti nirodha," which translates as, "Yoga is the stilling of the fluctuations of the mind." It makes sense that it helps us calm our negative feelings and become more emotionally resilient and intelligent because that's what it's supposed to do.

The fact that yoga helps you manage stress may help explain some of its other brain benefits -- for instance, stress is known to shrink the hippocampus, so anything that reduces stress likely reduces that shrinkage as well. 

Yoga is not the only health practice with brain benefits. Aerobic exercise, such as running has also been shown to benefit many of these same areas, which researchers found intriguing since yoga is not an aerobic form of exercise.

More study is needed to figure out exactly how these effects work, Gothe notes. In the meantime, I'm going to make sure to get to a yoga class this weekend. How about you?