 | Minding Your Mind | | |
Yoga -- Reduce Stress and Improve Your Mood
October 29, 2009  By Michael Craig Miller, M.D.
Harvard Medical School Since the 1970s, meditation and other stress-reduction techniques have been studied as possible treatments for depression and anxiety. One such practice, yoga, has received less attention in the medical literature, though it has become increasingly popular in recent decades. One national survey estimated, for example, that about 7.5% of U.S. adults had tried yoga at least once, and that nearly 4% practiced yoga in the previous year. There are many types of yoga. Hatha yoga, the most common type of yoga practiced in the United States, combines three elements: physical poses, called asanas; controlled breathing practiced in conjunction with asanas; and a short period of deep relaxation or meditation. Many of the studies evaluating yoga's therapeutic benefits have been small and poorly designed. But results from the growing number of randomized controlled trials, the most rigorous standard for proving effectiveness, suggest that yoga practices may be helpful for both anxiety and depression. In this respect, yoga is like other self-soothing techniques, such as meditation, relaxation, exercise, or even socializing with friends. Let's take a closer look at the research. Back to top Taming the Stress Response Yoga appears to modulate stress response systems by reducing the intensity of a person's reactions to anxiety-provoking experiences. This, in turn, decreases physiological arousal, such as heart rate, blood pressure and respiration. There is also evidence that yoga practices help increase heart rate variability. This is a sign of the body's ability to respond to stress more flexibly. A small but intriguing study published in 2008 further describes the effect of yoga on the stress response. Researchers at the University of Utah noted that people who have a poorly regulated response to stress are also more sensitive to pain. Their subjects were 12 experienced yoga practitioners, 14 people with fibromyalgia (a condition many researchers consider a stress-related illness that is characterized by hypersensitivity to pain) and 16 healthy volunteers. When the three groups were subjected to more or less painful thumbnail pressure, the participants with fibromyalgia — as expected — perceived pain at lower pressure levels compared with the other subjects. Functional MRIs showed they also had the greatest activity in areas of the brain associated with the pain response. In contrast, the yoga practitioners had the highest pain tolerance and lowest pain-related brain activity during the MRI. The study underscores the value of techniques like yoga that can help a person regulate stress and, therefore, pain responses. Back to top Improving Mood It's not clear exactly how yoga works to improve mood, but preliminary evidence suggests its benefit is similar to that of exercise and relaxation techniques. In a German study published in 2005, 24 women who described themselves as "emotionally distressed" took two 90-minute yoga classes a week for three months. Women in a control group kept up their normal activities. They were asked not to begin an exercise or stress-reduction program during the study period. All of the participants had experienced emotional distress for at least half of the previous 90 days. Although they were not formally diagnosed with depression, they reported higher-than-average levels of stress, anxiety and depression. At the end of three months, women in the yoga group reported improvements in those three areas. They also had more energy. Depression scores improved by 50%, anxiety scores by 30%, and overall well-being scores by 65%. Complaints of headaches, back pain, and poor sleep quality also cleared up much more often in the yoga group than in the control group. One uncontrolled study from 2005 described the effects of a single yoga class for inpatients at a New Hampshire psychiatric hospital. The 113 participants included people with bipolar disorder, major depression and schizophrenia. Before the class, they answered a questionnaire. After the class, average levels of tension, anxiety, depression, anger, hostility and fatigue dropped significantly when they repeated the questionnaire. Patients who chose to participate in additional classes experienced similar short-term positive effects. Further controlled trials of yoga practice have demonstrated improvements in mood and quality of life for the elderly, people caring for patients with dementia, breast cancer survivors and patients with epilepsy. Back to top Potential Benefits for PTSD Since evidence suggests that yoga can turn down nervous system arousal, researchers are exploring whether or not yoga can help patients with post-traumatic stress disorder (PTSD). One randomized controlled study examined the effects of yoga and a breathing program among disabled Australian Vietnam veterans diagnosed with severe PTSD. The veterans were heavy daily drinkers who were taking at least one antidepressant. The five-day course included breathing techniques, yoga asanas, education about stress reduction and guided meditation. Participants were evaluated at the beginning of the study using a standardized symptom scale. Six weeks after the study began, the yoga and breathing group experienced improvements in symptoms that remained at a six-month follow-up. The control group, made up of veterans on a waiting list, showed no improvement. About 20% of war veterans returning from Afghanistan or Iraq suffer from PTSD, according to one estimate. Experts treating this group of people suggest that yoga can be a useful addition to the treatment program. Researchers at the Walter Reed Army Medical Center in Washington, D.C., are offering a yogic method of deep relaxation to veterans returning from combat in Iraq and Afghanistan. Dr. Kristie Gore, a psychologist at the center, says the military hopes that yoga-based treatments will be more acceptable to the soldiers and less stigmatizing than traditional psychotherapy. The center now uses yoga and yogic relaxation in post-deployment PTSD awareness courses, and plans to conduct a controlled trial of their effectiveness in the future. Back to top A Word of Caution -- and Encouragement Although many forms of yoga are safe, some are strenuous and may not be appropriate for everyone. In particular, elderly patients or those with mobility problems may want to check first with a clinician before choosing yoga as a treatment option. But for many patients dealing with depression, anxiety or stress, yoga may be a very appealing way to better manage symptoms. Indeed, the scientific study of yoga demonstrates that mental and physical health are not just closely allied, but are essentially equivalent. The evidence is growing that yoga practice is a relatively low-risk, high-benefit way to improve overall health. Back to top Michael Craig Miller, M.D. is editor-in-chief of the Harvard Mental Health Letter and an assistant professor of psychiatry at Harvard Medical School. Dr. Miller has an active clinical practice and has been on staff at Beth Israel Deaconess Medical Center for more than 25 years.
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