Yoga is touted as a stress reliever, and there's growing biochemical evidence to support that belief.
For one week, 16 young adults who had not done yoga more than once took a 50-minute class with a traditionally trained teacher, co-investigator Vijayendra Pratap of the Philadelphia-based Yoga Research Society. For comparison purposes, the volunteers spent 50 minutes resting in a quiet room the day before the class began.
Blood levels of the stress hormone cortisol were statistically identical before and after the first day's rest period, says George Brainard, professor of neurology at Jefferson Medical College of Thomas Jefferson University in Philadelphia. But there was a significant decrease in the hormone after the yoga class.
This study, reported at the annual meeting of the Endocrine Society in June, confirmed earlier research showing that cortisol decreased after a single yoga class.