Overall, this study demonstrated that an evening yoga practice designed to improve sleep in middle aged to older women with OA was highly feasible and produced promising preliminary efficacy findings. Recruitment and retention were successful, with the study reaching full enrollment and experiencing only one drop-out (92% retention). Participants reported practicing the yoga program at home 83% of their nights in the study, and the mean practice duration (22.6 minutes) was longer than the time requested by the PI (20 minutes). Participants reported enjoying the class and desiring to continue yoga practice. Overall, these results support further research on a standardized yoga intervention for sleep disturbance in women with OA.
Our study showed similar retention rates to other studies of yoga for older adults but also produced new feasibility data on adherence of adults with OA to a nightly yoga practice. The mean duration of each practice session was similar to that found in a study of Kundalini Yoga (a style emphasizing meditation and breathing techniques) for persons with insomnia (mean practice = 24.4–28.8 minutes) [21
]. Retention rates of 82–92%, similar to our pilot study, have been observed in a series of yoga studies for health promotion in older adults (Silver Yoga) by Chen and colleagues [22
]. Interventions in these studies ranged from 1 to 6 months (N=16 to 204) [22
]. However, all of these studies were either one group pre-/post-test design or used wait-list controls. These data support the interest of older adults in yoga for health promotion, but such interest may also indicate that retention of participants in studies employing attention control groups may be particularly challenging in yoga research.
In addition to feasibility, the findings of this pilot study provide preliminary support for the efficacy of a standardized nightly yoga practice in middle aged to older women with OA. Sleep outcomes from questionnaires and diaries showed improvements after treatment, several of which were statistically significant (ISI; sleep diary SOL, SE, and nights with insomnia). Additionally, depressed mood (GDS) showed a trend toward improvement. Actigraphy-based outcomes were not statistically significant. It is possible that this 8-week pilot study was not long enough to impact actigraphic sleep outcomes. But discordance between subjective and objective measures is common in insomnia, and improvement of subjective sleep alone is of clinical importance for reducing symptoms experienced by patients. The overall outcomes are encouraging given that this feasibility study was not designed for statistical power to detect significant changes in the efficacy outcomes.
Research on the Silver Yoga program also examined sleep outcomes (PSQI scores) in older adults, although their sample was not limited to persons with OA. These studies showed improvements in physical outcomes (e.g., range of ROM, balance) as early as 4 weeks, but total PSQI scores were not significantly improved until 6 months of practice. We found improvements in PSQI scores (though not statistically significant) as well as significant improvement in other sleep outcomes after only 8 weeks of practice. The earlier onset of improvement in our study may be explained by inclusion of nightly relaxing practices in the evening yoga routine. Other studies have examined therapeutic yoga interventions designed to improve sleep. The previously discussed study of Kundalini Yoga for adults with insomnia (N=40, mean age 41.1 ± 10.0 years) found significant reduction of diary-reported total sleep time, total wake time, sleep efficiency, sleep onset latency, and wake after sleep onset in those who completed the study (N=21) [21
]., The efficacy of the intervention, however, supports inclusion of the yoga elements emphasized—breathing and meditative thought—in interventions for insomnia. The present study included breathing practices and mindful body awareness during relaxation poses. Another RCT found significant improvement in the sleep of older adults, but it employed an intensive therapy that trained participants 60 minutes per day, 6 days each week for 6 months [18
]. The intervention implemented in the present study produced significant improvement, and it was less intensive and time-consuming.
Pain (VAS) and disability (HAQ-DI) scores were not significantly reduced in this study. Disability scores were fairly low and may have encountered a floor effect. Given that other studies of yoga for OA pain found reduction of this symptom [11
], it was expected that the range-of-motion (ROM) exercises in this study would reduce participants’ pain. Lack of effect may have been related to inclusion of only mild strengthening exercises. Research has shown strengthening exercises to help with OA pain [47
]. A future study might benefit from a greater emphasis on strengthening practices that would increase joint stability.
Few side effects of the intervention occurred, all of which were minor. Safety of the intervention was supported by familiarity of both instructors with the limitations of persons with OA and modifications of yoga to meet such needs. This baseline knowledge will be important for future studies of yoga for OA. In a subsequent randomized controlled trial of the yoga program for sleep in OA, employing knowledgeable instructors and providing training on OA and acceptable modifications of yoga poses will be important for safety and standardization of this trial.
Certain limitations of the study should be addressed in subsequent trials of yoga for OA. The effects of the intervention, although promising, must be interpreted with caution as the study did not include a control group. In particular, the beneficial effects of general activation and social support (i.e., weekly class participation) are unknown. A subsequent study planned by our group will include an attention-control group to control for these factors. Additionally, this study was subject to the common limitations of research involving self-report. Although back-filling of diaries was reduced by collecting these forms weekly, there was still the potential for delayed completion of these forms. Electronic data collection would improve the accuracy of daily sleep and symptom reporting.
This feasibility and acceptability study showed that women with OA and sleep disturbance were highly interested in yoga as a potential treatment for their symptoms. Efficacy findings from the study were promising, showing significant improvements in several self-report sleep outcomes. These findings support the feasibility of a randomized controlled trial examining the effect of a yoga intervention on OA symptoms, such as sleep, pain, and depression in middle aged to older adults. Despite a glut of media and published information on yoga, it is difficult for patients and healthcare providers to judge the safety, quality, and potential benefits of any given yoga program or class. A standardized yoga program resulting from this research could provide both patients and practitioners with an evidence-based program that could be systematically implemented in the community setting and widely available as an option for management of sleep disturbances in persons with OA.