Julia Roberts, Madonna, Colin Farrell and Dr. Oz all do poses - yoga poses, that is - along with 20 million other North Americans.

The popularity of this practice, which originated in India, is thanks in large part to the guru B.K.S. Iyengar (he died at 95 in August 2014).

In 1952, the American-born violinist Yehudi Menuhin was visiting India when he was challenged to a headstand by Prime Minister Jawaharlal Nehru (remember the Nehru jacket?). Iyengar was there, and took the duo through poses.

The publicity launched a wave of interest in the discipline that's never ebbed.

The benefits of yoga are far-reaching (some aggressive or superheated styles, well, they aren't the best options for everyone).

Hatha yoga combines breathing techniques with poses that reduce stress, promote blood flow, flexibility and mental focus. It has been shown to ease everything from chronic lower-back pain and chronic inflammation to depression and elevated blood pressure.

Now a new study shows that for folks 59 to 77, it also can boost brainpower: Mental flexibility, information recall and task-switching abilities were far better in Hatha yoga participants than in a group who only did stretching and toning exercises.

What's the difference?

We suspect Hatha is brain-friendly because of its emphasis on stress-busting deep breathing (that provides more oxygen to those brain cells and protection of memory connections!) and intentional focus on slow movement that also helps control stress responses.

Want to try? Go to sharecare.com and search for "Yoga Starter" and other yoga instruction videos.

© 2014 Michael Roizen, M.D. and Mehmet Oz, M.D.
Distributed by King Features Syndicate, Inc.