More than 11 million Americans currently practice yoga, according to the American Council on Exercise.

Back in 2010, a comparative analysis study from researchers at the University of Maryland School of Nursing concluded that yoga may be as effective as, or even better than, exercise when it comes to improving health. What is actually happening in your body and brain? Here's the science behind this ancient practice.

PHYSICAL BENEFITS OF YOGA

In a study from the ACE, researchers at the University of Wisconsin, La Crosse, found that eight weeks of yoga improved average flexibility by 13 to 35 percent.

“We saw very nice changes in flexibility of the entire body, the shoulder girdle, twisting, bending, reaching, good low-back flexibility — all those types of flexibility improved,” said researcher John Porcari. ”And those improvements should have very good carryover to everyday life.”

Paula R. Pullen, PhD, Research Instructor at the Morehouse School of Medicine, also found that it reduced inflammation, according to Forbes.

HOW IT WORKS IN THE BODY

Yoga moves your body in the ways it was designed to; as a way to ensure that it keeps functioning properly. The practice can be traced back to over 5,000 years ago, but some researchers think that yoga may be up to 10,000 years old, according to Yoga Basics.

Additionally, when practicing yoga you’re limited to “lifting” your own body weight, Gaiam reported. This means that it may take a lot more skill, time, and determination to get it right, but the benefits are better than with just lifting weights.

“You’re putting your body in positions and orientations that you ultimately have to support with your muscles,” yoga expert Rodney Yee told Gaiam.

MENTAL BENEFITS OF YOGA

Back in August, a report published in the Journal of Psychophysiology showed how women who practiced yoga had lower levels of psychological distress as well as less perceived stress when they were compared to the women who did not practice.

Those in the yoga group not only saw a change in their stress levels, Medical Daily previously reported, but also began experiencing positive emotions and improved mood conditions.

HOW IT WORKS IN THE BRAIN

Yoga boosts levels of brain chemicals like GABA, serotonin, and dopamine — which all make you feel good and are responsible for relaxation and contentedness, Forbes reported. This is achieved by taking deep breaths, improving blood flow to the brain, and acutely focusing your attention for extended periods.

Practicing yoga is also linked to opening your mind to learn new things.

"It thickens the layers of the cerebral cortex, the part of the brain associated with higher learning, and increases neuroplasticity, which helps us learn new things and change the way we do things," Dr. Loren Fishman, a New York City physician who is also a yoga instructor, told LiveScience.

Read more:

Take A Deep Breath For Stress Relief: Yoga Could Help Improve Mood, Reduce Waist Size, Study Shows

Yoga For Brain Power: Mindfulness Exercises Reduce Effects Of Cognitive Impairment By Improving Memory, Mood