It is estimated that 30% to 90% of patients with cancer experience impairment of sleep quality post-treatment, and such impairment can be severe enough to increase morbidity and mortality. Preliminary evidence indicates that yoga may improve sleep in cancer patients.
In a study reported in the Journal of Clinical Oncology, Karen M. Mustian, PhD, MPH, of the University of Rochester Medical Center, and colleagues compared the effects of a standardized yoga intervention vs standard care on global sleep quality in patients with cancer experiencing sleep disruption.1 They found that yoga participants had significantly greater improvements in global sleep quality, subjective sleep quality, daytime dysfunction, wake after sleep onset, sleep efficiency, and medication use.
In this study, 410 patients aged 21 years or older with moderate or greater sleep disruption between 2 and 24 months after surgery, chemotherapy, or radiation therapy were randomized to standard care (n = 204) or standard care plus a 4-week yoga intervention (n = 206). To be eligible for the study, patients must have completed treatment for cancer and must not have maintained a regular practice of yoga within 3 months before the study or be planning to start yoga on their own during the next 4 weeks. Among other entry criteria, patients could not have a confirmed diagnosis of sleep apnea, could not be receiving any form of treatment for cancer, with the exception of hormonal or monoclonal antibody therapy, and could not have metastatic cancer.
The yoga intervention used the Yoga for Cancer Survivors (YOCAS) program consisting of pranayama (breathing exercises), 16 gentle hatha and restorative yoga asanas (postures), and meditation. Participants attended two 75-minute sessions per week. Standard care consisted of standard follow-up care provided by treating oncologists as appropriate for patients’ individual diagnoses.
The primary outcome measure was global sleep quality score on the Pittsburgh Sleep Quality Index (PSQI), and the subscale scores of global sleep quality characteristics were secondary endpoints. Objective sleep characteristics were assessed by actigraphy, a noninvasive method of monitoring human rest/activity cycles.
There were no significant differences between yoga and standard care groups in age (mean, 54 years in both), sex (96% women in both), race/ethnicity (96% and 91% white), marital status (married or long-term committed relationship in 71% and 72%), education level (47% of both completed college), employment status (83% and 78% employed), cancer type (breast in 74% and 77%), cancer stage (I or II in 68% and 72%, III in 16% of both, IV in 4% and 2%), previous cancer treatments (surgery in 90% and 91%, chemotherapy in 72% and 70%, radiation therapy in 67% and 65%), current hormone therapy (49% and 54%), time since first cancer treatment (mean, 14.9 and 17.7 months), Karnofsky performance status (mean, 86.9 and 87.8), or exercise status (53% and 51% exercising for less than or more than 6 months).
Yoga patients attended an average of 6.5 of the 8 prescribed sessions. Patients in the yoga group were told that they could practice the yoga they learned in class on their own; daily diaries showed that they had three sessions combining class-based and home-based yoga each week for an average of 182 minutes with a perceived exertion rating of 3.4 (moderate). In the control group, seven patients reported an average of 20 minutes of yoga one time each week with a perceived exertion rating of 1.0 (very weak) during the study
Improved Sleep Quality
Both groups met the clinical cutoff criterion for impaired sleep quality at baseline with PSQI scores > 8. Compared with the control group, the yoga group had a significantly greater improvement in global sleep quality (P < .01). The PSQI global sleep quality score improved from a mean of 9.20 at baseline to 7.23 (–1.96 difference) in the yoga group compared with improvement from 8.96 to 7.89 (–1.07) in the control group. Yoga patients exhibited large improvements in sleep quality compared with baseline (effect size [d] = 0.62), suggesting that the improvement was clinically significant, whereas improvement from baseline in the control group was less robust (d = 0.37).
Compared with the control group, the yoga group also had significantly greater improvements in the secondary outcome measures of daytime dysfunction (P < .01), subjective sleep quality (P < .05), and sleep medication use (P < .05). Yoga patients reduced sleep medication use by 21% per week, and control patients increased sleep medication use by 5% per week. Overall, 90% of the yoga group found yoga useful for improving their sleep quality, with 100% stating that they would recommend yoga to other cancer survivors with sleep problems and 63% stating they would highly recommend it.
Compared with baseline, the yoga group had significant improvements in sleep quality, including global sleep quality (P < .01), sleep latency (P < .01), sleep duration (P < .05), sleep efficiency (P < .01), sleep disturbances (P < .05), subjective sleep quality (P < .01), and daytime dysfunction (P < .01), but not sleep medication use. Compared with baseline, the control group had significant improvements in global sleep quality (P < .01), sleep efficiency (P < .05), sleep disturbance (P ≤ .01), and subjective sleep quality (P < .01), but not in sleep latency, sleep duration, daytime dysfunction, or sleep medication use.
Actigraphy studies showed that the yoga group had significantly greater improvements in wake after sleep onset (P < .01) and sleep efficiency (P < .01) compared with the control group. Patients in the yoga group who had 60 minutes or more of wakefulness after sleep onset or a sleep efficiency of ≤ 60% at baseline showed the greatest reductions in wake after sleep onset and the greatest improvements in sleep efficiency.
One patient had supraventricular tachycardia during the study period, which was considered grade 2 and unrelated to the study intervention. No other serious adverse events were reported.
The investigators concluded, “Yoga, specifically the YOCAS program, is a useful treatment for improving sleep quality and reducing sleep medication use among cancer survivors.” They noted that further phase III studies are needed to replicate their findings, assess the effects of increased length and intensity of yoga, provide long-term follow-up of the sustainability of benefits, and to compare yoga with such established treatments as cognitive behavioral therapy and drug treatments. They also stated that additional research should examine the potential impact of yoga on cancer recurrence and survival rates. ■
Disclosure: The study was supported by the National Cancer Institute and the Office of Cancer Complementary and Alternative Medicine. The study authors reported no potential conflicts of interest.
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