Rao, R.M., Vadiraja, H.S., Nagaratna, R., Gopinath, K.S., Patil, S., Diwakar, R.B., . . . Nagendra, H.R. (2017). Effect of yoga on sleep quality and neuroendocrine immune response in metastatic breast cancer patients. Indian Journal of Palliative Care, 23, 253–260.

The purpose of this study was to test the effects of a yoga program to determine impact on perceived stress, sleep, diurnal cortisol, and natural killer cell counts in patients with metastatic cancer compared to education and supportive therapy sessions.

Patients with advanced metastatic breast cancer were recruited from a comprehensive cancer center in the medical and radiation outpatient clinics. Consenting patients were randomized to yoga or supportive therapy groups. Providers of oncology care were blinded to group assignment. The yoga program intervention included two sessions a week for 12 weeks. Each session started with a lecture and yoga for 10 minutes followed by 20 minutes of low-impact yoga postures, breathing, and pranayama and relaxation. Then, subjects completed 30 minutes of guided yoga practice by one of two trained instructors. Practicing was encouraged between sessions with instructions and booklets documented in diary logs. The control group completed supportive care sessions, including education and reinforcing social support. Introductory sessions were 60 minutes before starting treatment and during each treatment visit for 15 minutes. Participants could contact counselors at any time with issues or questions. Diary logs were also completed.

• N = 91   
• AGE: Mean 49.6 years
• FEMALES: 100%
• CURRENT TREATMENT: Combination radiation and chemotherapy
• KEY DISEASE CHARACTERISTICS: Diagnosed with stage IV breast cancer within six months of enrollment with no brain involvement 
• OTHER KEY SAMPLE CHARACTERISTICS: No active steroids, unable to perform exercise, psychiatric, neurological, autoimmune disorder. No pregnancy or lactating mothers.

• SITE: Single site   
• SETTING TYPE: Outpatient    
• LOCATION: Comprehensive cancer center, India

• PHASE OF CARE: Active antitumor treatment
• APPLICATIONS:  Palliative care

Two-arm, prospective randomized control trial

The Pittsburgh Insomnia Rating Scale was used to measure distress related to sleep, sleep parameters, and sleep-related quality of life. Salivary cortisol was measured using oral swab on three consecutive days at three time points. Natural killer cells were collected at baseline and at the end of the study using serum samples to determine immune response. A daily diary was used to document yoga practice in the intervention group and control group.

Of the 91 baseline participants, complete data were analyzed on 66. Reasons for high dropout were listed. No demographic group differences were noted at baseline. Within-group findings included significant decreased distress scores (p = 0.004), decreased sleep distress scores (p = 0.01), improved sleep quality-of-life scores (p = 0.006), improved sleep total distress scores (p = 0.002), decrease in cortisol (p = 0.03), and natural killer cells (p < 0.01) in the yoga group alone. Intervention adherence was 80% attending 24 supervised sessions. Attending more than 20 sessions showed the decreased 9 am cortisol level in the yoga intervention group.

There was evidence to support that yoga could be impacting sleep distress, sleep outcomes, and sleep quality of life, as well as neuroendocrine immune changes providing mechanistic information regarding the benefits of yoga on sleep. Additional research is needed to generalize findings to a wider cancer population.

• Small sample (< 100)
• Risk of bias (no blinding)
• Subject withdrawals ≥ 10%
• Other limitations/explanation: Inequality of intervention contact duration between groups

When recommending yoga as an intervention for sleep, there is a potential impact on subjective sleep outcomes, quality of life, and neuroendocrine responses such as immune function and cortisol levels.