By Shirley Vanderbilt
Originally published in Massage & Bodywork magazine, October/November 2004.
Once associated primarily with Indian gurus and counterculture enthusiasts, yoga has grown in popularity and is embraced by Americans from all walks of life. In a recent issue of Alternative Therapies in Health and Medicine (March/April 2004), researchers from Harvard Medical School reported statistics gleaned from David Eisenberg’s well-known 1998 survey on the use of complementary and alternative medicine (CAM) in the United States. This previously unpublished data reflects yoga use over the respondents’ lifetime, with an additional subset of data established for current yoga users. Results indicate that of the estimated 15 million adults who have used yoga at least once during their lifetime, approximately half did so in 1998. “Respondents who practiced yoga in 1998 used it both for wellness and common health conditions (especially back or neck problems), often with high degrees of perceived helpfulness,” the team writes.1
While the study does not tell us anything about the types of yoga being practiced or frequency of use, it does indicate this modality is a popular, low-cost alternative for those seeking good health. Underlying this is the assumption by many that yoga is safe and effective for a variety of purposes. And yet, as the authors point out, there is little in our Western scientific literature to support these claims. Trials have been, and continue to be, small, some with the usual methodological flaws of inadequate sample sizes and control group issues. The team’s urging for larger clinical studies is echoed in several related reports in this particular issue of Alternative Therapies in Health and Medicine.
In his introduction, the journal’s editor-in-chief, David Riley, M.D., points out the three basic ingredients of Hatha yoga, the most familiar form of practice in our country: Postures (asana), which strengthen the body and increase flexibility; breathing exercises (pranayama) for relaxation and focus; and meditation (dhyana), also for calming and focusing the mind. Included in our Western conjecture of physiological explanations for Hatha yoga’s effectiveness in the treatment of illness, he writes, are modulation of the autonomic nervous system tone, stimulation of the limbic system, and increased range of motion and relaxation response through activation of antagonistic neuromuscular systems.2
As the popularity of Hatha yoga has grown, so have individual styles and approaches. The positive aspect of this diversity is that those using yoga can seek out the method best suited to their needs and abilities. Riley recommends Iyengar and Viniyoga as “most appropriate for those with specific medical conditions.” Iyengar, which uses props for added support, emphasizes alignment; Viniyoga gives attention to “the individualized nature” of the practice.3 We begin our review of what’s new with the journal’s report on two randomized controlled trials (RCT) on chronic low back pain.
Lessons and Applications
Noting that Iyengar is the most commonly practiced style of Hatha yoga in the United States, the research team of Jacobs et al. from California’s Osher Center for Integrative Medicine applied this practice to subjects with chronic low back pain. Their hypothesis report includes not only some baseline randomization data but also reflections on the “unique challenges and particular issues that must be addressed with any rigorous research of the medical applications of Hatha yoga.”4
What exactly did they learn? Although small in sample size (52 total subjects), the study — defined as “a pilot, randomized, two-arm, open-label, wait-list controlled, clinical trial”5 — demonstrated some success in feasibility for a larger trial. One of the more progressive aspects was the inclusion of an eight-member panel of Iyengar experts, nationally and internationally known, each with more than 10 years of teaching experience. Their job was to design an experimental protocol that would produce the desired clinical results. Consensus was for 90-minute, semiweekly classes for 12 weeks, with home practice of 30-minute sessions, five times weekly. Specific asanas were included along with a semi-structured approach in which the individualized needs of each subject could be addressed in adherence to yoga tradition. Additionally, the instructors chosen for intervention represented a well-trained cadre, with a minimum of 10 years experience teaching yoga as well as experience working with clients with chronic back pain.6
The majority of massage research aside, it is not uncommon for CAM studies to be cited as flawed because of less than well-thought-out protocol or ambiguity (or other factors) related to training level of practitioners applying the experimental treatment. To take the lead from this team would seem to bode well for the success of larger clinical trials.
Recruitment of subjects was fairly successful, completed within three months, but the team experienced minor difficulties with adherence to the yoga routine. Addressing this factor, they suggest an introductory session for volunteers, highlighting theory and practice and emphasizing the personal commitment involved. Researchers also note the demands for allocation of staff to scheduling and implementing intervention far exceed those in conventional studies, such as pharmaceutical trials in which medication is dispensed and later evaluated.7 Yoga research requires an ongoing expenditure of time and energy, both on the part of subjects and the intervention team.
The team of Galantino et al., in a smaller pilot project, also focused on assessing protocol for application of yoga in treating chronic low back pain. The authors write, “The sample size of this pilot study was not intended for an efficacy analysis but rather to obtain an estimate of the effect size and variance necessary to plan a definitive study, to test and refine individual components of the yoga protocol and measurement tools.” However, results did suggest benefit for improvement in balance and flexibility as well as decreased depression.8
The 22 subjects were randomized equally to modified yoga-based intervention or a control group, with the yoga group receiving formal instruction twice weekly over six weeks and encouraged to continue daily practice at home. Subjects in the control group were instructed to maintain their regular routine and were wait-listed for a similar course of yoga instruction following completion of the study. Despite this incentive, the control group suffered attrition with six subjects dropping out.9 Incorporating other types of interventions into the design, such as movement or physical therapy, is suggested as a possible solution. Additionally, it was found that even with the yoga group reporting benefit, none continued the practice after study completion. The authors emphasize these issues be considered in planning larger scale studies.10
Based on their findings, the team recommends use of several measurements included in the study: Oswestry Disability Index, Functional Reach Test, and Sit and Reach Test. To this they would add pain and discomfort scales along with “an appropriate measurement of the yoga psychological aspect.” These measurements could provide more complete data related to the impact of yoga on functional and emotional well-being. While gleaning important lessons regarding suitable assessment tools, authors note a possible confounding factor of nonspecific effects. It’s feasible that the socialization and mutual support available to subjects meeting together as a yoga group could have impacted on their overall improvement.11
Similar to the Jacob study, Galantino’s team utilized a panel of experts to develop intervention protocol. Two Hatha yoga instructors with more than 10 years of experience were joined by a physical therapist specializing in spine treatment. With yoga postures adapted to the abilities of individual subjects, the protocol also included meditation/relaxation at the beginning and end of sessions. In addition to formal, biweekly classes over six weeks, participants were encouraged to practice one hour daily between sessions, within parameters of personal comfort.12 Both studies, while limited in statistical application, provide a solid base from which to expand into larger clinical trials.
Tidbits of Results
Data from several small exploratory studies and RCTs are also presented in the form of research letters and brief reports in the journal’s yoga-focused issue. Woolery et al., from the psychology department of University of California, Los Angeles, chose the Iyengar method for their study of effects on mild depression in young adults. Comparing a wait-list control group (n=15) to yoga participants (n=13), the team combined self-report measures with cortisol samples to substantiate benefits. The yoga group met twice weekly, over five weeks, for a one-hour session featuring postures recommended to alleviate depression. Attrition was again a problem, with three yoga and two control subjects dropping out despite the incentive of a $30 gift certificate for participation. A significant reduction in depression was found in the yoga group as compared to control, with this benefit evident by mid-course and continuing to completion. However, the team is cautious with interpretation, noting methodological problems and that various aspects of class participation, aside from the actual practice, could have impacted enhanced mood.13
McIver et al. conducted a one-group, pretest/post-test design with 20 residents of a drug/alcohol rehabilitation center to determine yoga’s influence on a desire to quit smoking. Subjects participated in once-weekly, hour-long sessions combining simple yoga stretches and breath awareness, over a period of five weeks. Positive results included one person ceasing smoking entirely, with 30 percent of participants noting a shift toward a desire to quit.14 Another preliminary study by DeMayo et al. involved participation of 23 patients with post-polio syndrome in a yoga retreat, continuing with 12 weeks of follow-up home practice aided by video instruction. As an investigative beginning for developing longitudinal data collection on the application of Hatha yoga in ongoing care and education, the project’s results were positive. Data collected at both retreats’ end and completion of the home practice period indicated significant improvement in measurements of weakness, pain, and self-efficacy, as well as two of three fatigue scales, with the bonus that patients were actively involved in their self-care.15
Adding to this fund of newsworthy tidbits are some recent postings on the PubMed website, a National Library of Medicine database of journal citations. In the Journal of Clinical Psychology (June 2004), a psychology team reports benefit of a yoga-meditation program for dementia caregivers. Results of the small (n=12) pilot study indicated significant reduction of depression and anxiety in the caregivers, along with subjects’ reports of improvement in physical and emotional function.16
Reporting in Respirology (March 2004), researchers at Vivekananda Yoga Research Foundation in Bangalore, India, investigated yoga as a complementary therapy for patients with pulmonary tuberculosis. In this RCT, subjects were randomized to yoga (n=25) and breath awareness practice (n=23) for one-hour sessions, six times per week over a two-month period. Significant emphasis was placed on laboratory measurements. Results were more dramatic for the yoga group, with improved infection levels, weight gain, reduced symptoms, and improvement in chest X-ray and pulmonary function tests.17
It’s important to keep in mind the majority of these results are preliminary, with most studies serving as precursors to development of larger, more solid RCTs. And as Riley cautions, not all types of yoga are applicable to specific medical conditions, and some, such as Bikram with its emphasis on heat, would be contraindicated for certain patients.18 As results come in and knowledge of application becomes more refined, yoga moves gradually and purposefully — like its asanas — toward confirming its value in integrative medicine.