A study published in The Journal of Alternative and Complementary Medicine found that yoga combined with coherent breathing instruction significantly reduced symptoms in people with major depressive disorder.

Major depressive disorder (MDD), which is also known simply as depression, is characterized by persistent depressed mood along with a loss of interest in daily activities, low energy, and pain without an obvious cause that interferes with daily activities and enjoyment of life. It is commonly treated with medication or psychotherapy (talk therapy), or a combination of the two.

In the study, adults 18 to 64 years of age with MDD participated in either three (high-dose intervention) or two (low-dose) yoga classes per week and practiced coherent breathing at five breaths per minute. Symptoms of depression were measured at the beginning and throughout the 12-week study.

Volunteers who took three yoga classes a week were more likely to achieve lower depression scores after 12 weeks than subjects who took two classes.

"The practical findings for this integrative health intervention is that it worked for participants who were both on and off antidepressant medications, and for those time-pressed, the two times per week dose also performed well," says John Weeks, Editor-in-Chief of The Journal of Alternative and Complementary Medicine.

The study was conducted by researchers from major institutions including Harvard School of Medicine and Columbia University College of Physicians and Surgeons.

Other recent studies have found that yoga is beneficial for a number of health issues. A study by scientists at the University of Maryland School of Medicine concluded that yoga may ease low back pain and improve ease of movement in patients.

Researchers from Boston's Massachusetts General Hospital found that people who practice deep relaxation techniques, including yoga and meditation, make 42 percent fewer trips to their doctors, and lab use dropped by 44 percent when compared to the year before training.

Yoga may also be a safe and effective way for people with arthritis to keep moving, according to a study from Johns Hopkins. A group of 75 volunteers with two common forms of arthritis, knee osteoarthritis and rheumatoid arthritis, were either put on a wait list or participated in twice-weekly yoga classes plus a weekly at-home session.

After eight weeks, those who were in the yoga group reported a 20 percent improvement in pain, mood, and the ability to perform daily activities when compared to the control group.