In one of the earliest controlled studies of a yoga-based protocol, Garfinkel and colleagues [10
] assigned 42 patients having pain from carpal tunnel syndrome to either an Iyengar-based Hatha yoga protocol or a control condition (wrist splint). Yoga classes focused on training in postures and relaxation techniques adjusted for the patient population. When compared to the control, patients receiving yoga showed significant reductions in pain and an increase in grip strength. Trends towards improvement were reported in motor nerve conduction time, Tinel sign, and sleep disturbance among the yoga group, though these were not significant. Garfinkel and colleagues [9
] also conducted a controlled study with hand osteoarthritis (OA) patients showing that Iyengar-based Hatha yoga tailored to the patient population produced significant improvements in pain during activity, joint tenderness, and finger range of motion compared to the control. There were no significant differences in hand pain at rest, hand function, hand grip strength, or circumference of finger joints. Taken together, these studies [9
] were important in stimulating research on yoga for pain control. Although studies appearing in the late 1990s and early years of 2000 supported the potential efficacy of yoga for managing pain conditions, these studies did not use randomized controlled designs [5
Several recent randomized controlled studies have tested the efficacy of Iyengar and Hatha yoga for persistent low back pain. Persistent low back pain is a particularly appropriate model for yoga research because it is common and related to musculoskeletal problems (e.g., pain avoidant posturing) and psychosocial stress. Williams and colleagues [25
] tailored their Iyengar yoga intervention to address back pain, providing specific protocol adjustments: a) patients practiced poses that used props to relieve tension and bring awareness to body regions, b) training progressed to lengthen, strengthen, and relax core muscle groups in the spine and pelvis, and c) training was provided over a graded series of movements involving twisting, bending, and stretching. Compared to an educational control, patients receiving yoga showed significant reductions in pain, functional disability, and pain medication at post-treatment and 3 month follow-up. No significant between group differences were reported in spinal range of motion, fear of movement, pain attitudes, self-efficacy, and coping strategies. In another study, Williams and colleagues [24
] reported that Iyengar yoga, tailored to chronic low back pain patients, produced significant reductions in pain, physical disability, and depression. The yoga group demonstrated a higher success rate than controls in decreasing pain medication, though this was non-significant. At 6-month follow-up, these benefits were maintained with 68% of patients in the yoga condition reporting regular home practice with yoga techniques. In another low back pain study, Sherman and colleagues [20
] found that Viniyoga, a therapeutically oriented yoga school, was significantly more effective than either aerobic exercise or an educational control in decreasing the bothersomeness of low back pain and pain-related disability. This study did not find any significant improvements on the SF-36. Additionally, Saper and colleagues [17
] reported that a Hatha yoga program designed for low back pain significantly reduced pain scores, back-related function, and pain medications among a diverse population of patients with low back pain (83% racial/ethnic minority). No significant differences were reported on SF-36 scores.
Recently, Carson and colleagues [4
] conducted a controlled study evaluating the efficacy of a tailored yoga program (Yoga of Awareness), derived from Kripalu yoga, for female fibromyalgia patients. Compared to the control, the yoga group showed significant improvements in fibromyalgia outcomes including pain, fatigue, vigor, mood, acceptance, pain catastrophizing, and other coping strategies. No significant between-group differences were reported on symptoms of tenderness, balance duration, poor sleep, and distancing and confrontation coping strategies.
The efficacy of yoga for pain control has also been tested among disease populations who have conditions that can be chronically painful. Pain symptoms are a primary complaint among end stage renal disease patients, which has led to a randomized yoga intervention for end stage renal disease-related pain, as well as other symptoms. Yurtkuran and colleagues modified a Hatha yoga protocol to address the fatigue and physical deconditioning experienced by this chronically ill population (e.g., progressively increasing practice from 15 to 30 minutes, moving from chair-based yoga to standing postures) [27
]. To enhance access to treatment, yoga training was provided in the hemodialysis clinic. Compared to standard care, yoga significantly decreased pain, fatigue, and sleep disturbance, and improved grip strength, cholesterol, urea, creatinine, and alkaline phosphatase levels, as well as erythrocyte and hematocrit counts. No significant between group changes in calcium, phosphorus, HDL-cholesterol or triglyceride levels were found. The authors suggest that yoga not only enhances pain management, but also has physical benefits similar to those seen with aerobic exercise.
Although interest in yoga for cancer-related pain management is growing, many studies are uncontrolled [3
]. Recently, Carson and colleagues [2
] conducted a randomized study of yoga for breast cancer survivors, based on Kripalu yoga (Yoga of Awareness). Compared to a wait-list control, a yoga intervention, which was tailored for breast cancer survivors, produced significant improvements in joint pain, symptom-related bother, fatigue, sleep disturbance, vigor, and hot flashes post-treatment. No significant between-group differences were reported for negative mood, relaxation, acceptance, or night sweats post-treatment. Interestingly, at 3 months follow-up, significant improvements were reported for patients in the yoga condition for negative mood, relaxation, and acceptance, in addition to the maintenance of previous treatment gains. Daily analyses showed that those who spent more time practicing yoga had the largest improvements in pain-related symptoms.
Of the four RCTs identified and not described in the text of this review, three had positive findings on pain-relevant outcomes [12
] and one reported non-significant outcomes [8
]. These studies were not included in the text because in three pain was not a primary outcome measure (e.g., measured via pain-related disability) [8
], and in two the yoga intervention was less generalizable to clinical settings (e.g., met eight hours daily for one week) [12