Many studies have shown that exercise in general can alleviate anxiety and depression, but it's not always clear which type of exercise produces the most benefit.
A recent study done at the Boston University School of Medicine compared the impact of walking vs. yoga on anxiety and depression.
The results suggested that the practice of yoga improved mood more effectively than walking, apparently by enhancing the production of the neurotransmitter GABA in the brain. GABA, also known as gamma aminobutyric acid, is the main inhibitory or calming neurotransmitter in the nervous system; it tends to reduce anxiety and produce relaxation.
In this study, 19 people practiced yoga for 60 minutes three times weekly for 12 weeks, while 15 participants did a metabolically similar walking program for the same period of time.
Researchers assessed the participants' moods and the level of GABA in their brains at the beginning and end of the study.
At the end of the 12 weeks, the subjects who had engaged in yoga had greater improvement in mood and less anxiety than the walking group. They also had higher levels of GABA in their brain as measured on an MRI scan.
This was the first study to show that a behavioral treatment like yoga contributed to elevated GABA levels in the brain, and that this change was also associated with a positive improvement in mood.
A pilot study from Boston University in 2007 showed that a single, one-hour yoga session also resulted in elevated GABA levels in the brain — in fact, GABA levels increased by 27 percent in the yoga group compared with no change in the control group.
Many prescription medications that reduce anxiety or induce sleep, such as the benzodiazepines (Valium, Ativan, Restoril, etc.) and drugs like Ambien, work by increasing GABA levels in the brain.
While many people respond to these medications, they are habit-forming and difficult to stop once you take them on a regular basis.
Practicing yoga is an alternative way to reduce anxiety and also reduce the need for these habit-forming drugs.