The pathophysiology of insomnia, as well as its relationship with cancer and cancer treatments, is largely unexplained.14,37,38 Research suggests that insomnia symptoms may arise through multiple pathophysiologic pathways, including dysregulated hypothalamic-pituitary-adrenal (HPA) axis function stemming from abnormal sleep/wake homeostasis; hyperarousal; disruptive cognitive and behavioral factors; and impaired circadian, physical (i.e. cardiopulmonary and muscular), and immune function. Cancer and its treatments directly and negatively influence these same physiologic processes and, therefore, can directly affect the development of insomnia. Cancer and its treatments also lead to a reduction in physical activity and exercise, resulting in physical deconditioning that, in turn, leads to diminished function in these same systems, further impairing sleep. Yoga is a form of exercise capable of positively influencing each of these systems and of improving circadian, physical, and immune function. While not exhaustive, we provide examples of plausible mechanistic pathways through which yoga may ameliorate the insomnia symptoms experienced by cancer patients.
Yoga and the Circadian Clock System
Yoga may regulate circadian function by acting as an exogenous behavioral nonphotosensitizer for the circadian clock system. The circadian clock system consists of a central component: the suprachiasmatic nucleus (SCN) of the hypothalamus, also known as the body’s ‘master clock,’ as well as peripheral components involving multiple organ- and tissue-specific ‘clocks.’ These peripheral clocks are synchronized through humoral and neural connections throughout the body that, in turn, affect behavioral and physiologic output rhythms (i.e. diurnal fluctuations in sleep, physical activity, heart rate, strength, and cytokines).39–41 The master clock, however, has its own intrinsic rhythm that is entrained or synchronized to a 24-hour cycle by exogenous photo- and nonphotosensitizers. While the strongest photosensitizer is light, one of the strongest nonphotosensitizers is exercise (e.g. yoga).41 Our prior research suggests that yoga favorably alters circadian activity rhythms as a behavioral nonphotosensitizer and can, thereby, address cancer-related insomnia.31
Yoga, the Immune System, and Inflammatory Responses
Yoga may regulate immune function in the same way as other modes of exercise: by dampening the chronically upregulated pro-inflammatory responses exhibited in cancer patients as a result of their disease and its treatments. This dampening, in turn, may normalize overall inflammatory responses and improve insomnia. Exercise reduces low-grade inflammation by triggering the immediate, but transient, release of interleukin (IL)- 6.42 IL-6 is released from skeletal muscle in proportion to exercise intensity and duration, the proportion of muscle mass used during an exercise bout, and training status.42 In this environment, IL-6 functions as an antiinflammatory molecule by triggering the release of tumor-necrosis factor receptor-1 (TNFR1), IL-10, and IL-1rα that, consequently, inhibits the production of tumor-necrosis factor alpha (TNFα), IL-8, IL-1α, and IFNγ and regulates overall inflammatory responses.42 Research suggests that yoga may improve inflammatory immune responses in cancer patients.43–45
Yoga and Physical Function in the Cardiopulmonary and Muscular Systems
Yoga may improve physical function (i.e. cardiopulmonary and muscular function) in the same way as other modes of exercise: by eliciting a physiologic conditioning response. This physical conditioning response may improve the reduced physical function exhibited by cancer patients as a result of their disease and its treatment, consequently improving insomnia. It is well documented that traditional modes of exercise, performed frequently at high enough intensities for a sufficient duration, improve cardiopulmonary and muscular function as part of a desirable physical conditioning response.46,47 In addition, regular exercise that improves physical function (cardiopulmonary and muscular) results in medium to large improvements in total sleep time, slow wave or ‘deep’ sleep, nighttime wakefulness, sleep onset latency, and insufficient sleep.48–51 Research suggests that participation in yoga improves cardiopulmonary and muscular function in healthy individuals and in those with other diseases.52–57
Yoga for the Treatment of Insomnia
Studies demonstrate that yoga may help to improve depression, anxiety, fatigue, and sleep difficulties in both a disease-free population and those with cancer.58–60 We review below the existing scientific literature on the use of yoga for the treatment of insomnia within an oncologic population.
Qualitative Yoga Studies/Yoga Program Evaluations
There have been a number of studies that obtained their data through program evaluations or through qualitative measures.61–64 Studies of this nature are useful in showing patient-reported benefits, but often carry less scientific weight because of their lack of randomization and validated outcome measures. One of the first examinations of yoga in cancer patients was performed by Joseph et al. in 1983.62 Cancer patients undergoing radiation therapy were offered yoga, meditation, or support therapy. Those in all three groups, reported improvements in sleep, treatment tolerance, mood, appetite, and QOL. A similar study was published in 2004, in which cancer patients were invited to participate in the Stanford Cancer Supportive Care Program (SCSCP).63 The SCSCP consisted of 11 activities, including fatigue management, nutrition, massage, and Restorative yoga. Of the 380 participants who participated in Restorative yoga and evaluated their experience, 96 % felt it reduced their stress, 74 % felt an increase in energy, and 65 % reported more restful sleep. In 2008, Duncan et al. described how yoga can be used to treat symptoms and QOL in cancer patients.61 Using pre/post analyses, yoga participants reported significant gains in overall well-being and reductions in the severity of their most bothersome symptoms. In a 2010 study of a yoga program of 17 breast cancer patients, yoga participants reported improvements in QOL and psychosocial functioning.64 Furthermore, yoga participants in two of these publications attributed improvements in strength, physical function, and physical fitness to their yoga program. While these results are extremely promising, they must be interpreted with caution due to their use of convenience samples and the lack of validated outcome measures for assessing sleep quality. Additionally, these programs did not use standardized versions of yoga, making it difficult to replicate the various interventions that were used.
A total of 11 clinical trials of yoga for insomnia and sleep difficulties in cancer patients were identified.20,25,28,30,34,36,65–69 Some of the trials used cancer patients on active therapy, while others used cancer patients who had already completed their primary therapy but still reported symptoms and side effects. These trials were very diverse, with the number of yoga classes ranging from one to five per week. Class duration also varied from 50 minutes to 120 minutes per session. There was also a very wide range regarding the duration of the intervention, with some studies lasting only 4 weeks and others lasting as long as 26 weeks. Perhaps most varied were the different types of yoga postures and poses used within these studies. Despite the use of different types of yoga, these studies showed that yoga was safe, feasible, and acceptable within cancer patient populations, reinforcing the findings from the previous section.
Yoga for the Treatment of Insomnia Among Cancer Patients— Evidence, Mechanisms of Action, and Clinical Recommendations
- Ancoli-Israel S, Recognition and treatment of sleep disturbances in cancer, J Clin Oncol, 2009;27:5864–6.
- Savard J, Ivers H, Villa J, et al., Natural course of insomnia comorbid with cancer: an 18-month longitudinal study, J Clin Oncol, 2011;29:3580–6.
- Palesh OG, Roscoe JA, Mustian KM, et al., Prevalence, demographics, and psychological associations of sleep disruption in patients with cancer: University of Rochester Cancer Center-Community Clinical Oncology Program, J Clin Oncol, 2010;28:292–8.
- Berger AM, Farr LA, Kuhn BR, et al., Values of sleep/wake, activity/rest, circadian rhythms, and fatigue prior to adjuvant breast cancer chemotherapy, J Pain Symptom Manage, 2007;33:398–409.
- Ancoli-Israel S, Liu L, Marler MR, et al., Fatigue, sleep, and circadian rhythms prior to chemotherapy for breast cancer, Support Care Cancer, 2006;14:201–9.
- Savard J, Simard S, Blanchet J, et al., Prevalence, clinical characteristics, and risk factors for insomnia in the context of breast cancer, Sleep, 2001;24:583–90.
- Schultz PN, Klein MJ, Beck ML, et al., Breast cancer: relationship between menopausal symptoms, physiologic health effects of cancer treatment and physical constraints on quality of life in long-term survivors, J Clin Nurs, 2005;14:204–11.
- Berger AM, Grem JL, Visovsky C, et al., Fatigue and other variables during adjuvant chemotherapy for colon and rectal cancer, Oncol Nurs Forum, 2010;37:E359–69.
- Savard J, Morin CM, Insomnia in the context of cancer: a review of a neglected problem, J Clin Oncol, 2001;19:895–908.
- Pinto AC, de Azambuja E, Improving quality of life after breast cancer: dealing with symptoms, Maturitas, 2011;70:343–8.
- Palesh O, Peppone L, Innominato PF, et al., Prevalence, putative mechanisms, and current management of sleep problems during chemotherapy for cancer, Nat Sci Sleep, 2012;4:151–62.
- Partinen M, Hublin C, Epidemiology of sleep disorders, Philadelphia: Elsevier, 2005.
- Mustian KM, Sprod LK, Janelsins M, et al., Multicenter, randomized controlled trial of yoga for sleep quality among cancer survivors, J Clin Oncol, 2013;26:3233–41.
- Palesh O, Peppone L, Innominato P, et al., Prevalence, putative mechanisms, and current management of sleep problems during chemotherapy for cancer, Nat Sci Sleep, 2012;4:151–62.
- Bower JE, Woolery A, Sternlieb B, Garet D, Yoga for cancer patients and survivors, Cancer Control, 2005;12:165–71.
- Elkins G, Fisher W, Johnson A, Mind-body therapies in integrative oncology, Curr Treat Options Oncol, 2010;11:128–40.
- Mustian KM, Morrow GR, Carroll JK, et al., Integrative nonpharmacologic behavioral interventions for the management of cancer-related fatigue, The Oncologist, 2007;12:52–67.
- Mustian KM, Sprod LK, Palesh OG, et al., Exercise for the management of side effects and quality of life among cancer survivors, Curr Sports Med Rep, 2009;8:325–30.
- Kirk M, Boon B, Hatha Yoga for greater strength, flexibility, and focus, Champaign, IL: Human Kinetics, 2003.
- Cohen L, Warneke C, Fouladi RT, et al., Psychological adjustment and sleep quality in a randomized trial of the effects of a Tibetan yoga intervention in patients with lymphoma, Cancer, 2004;100:2253–60.
- Saper RB, Eisenberg DM, Davis RB, et al., Prevalence and patterns of adult yoga use in the United States: results of a national survey, Altern Ther Health Med, 2004;10:44–9.
- Smith KB, Pukall CF, An evidence-based review of yoga as a complementary intervention for patients with cancer, Psycho- Oncology, 2009;18:465–75.
- Muktibodhananda S, Hatha Yoga Pradipika, Poughkeepsie, NY: Nesma Books India, 2000.
- Lasater J, Relax and Renew: Restful Yoga for Stressful Times, Berkeley, CA: Publishers Group West, 1995.
- Danhauer SC, Mihalko SL, Russell GB, et al., Restorative yoga for women with breast cancer: findings from a randomized pilot study, Psycho-Oncology, 2009;18:360–8.
- Danhauer SC, Tooze JA, Farmer DF, et al., Restorative yoga for women with ovarian or breast cancer: findings from a pilot study, J Soc Integr Oncol, 2008;6:47–58.
- Bower JE, Garet D, Sternlieb B, et al., Yoga for persistent fatigue in breast cancer survivors: a randomized controlled trial, Cancer, 2012;118:3766–75.
- Carson JW, Carson KM, Porter LS, et al., Yoga of Awareness program for menopausal symptoms in breast cancer survivors: results from a randomized trial, Support Care Cancer, 2009;17:1301–9.
- Ulger O, Yagl NV, Effects of yoga on the quality of life in cancer patients, Complement Ther Clin Pract, 2010;16:60–3.
- Vadiraja SH, Rao MR, Nagendra RH, et al., Effects of yoga on symptom management in breast cancer patients: a randomized controlled trial, Int J Yoga, 2009;2:73–9.
- Mustian KM, Janelsins M, Sprod L, et al., YOCAS©® Yoga significantly improves circadian rhythm, anxiety, mood and sleep: a randomized, controlled clinical trial among 410 cancer survivors, Support Care Cancer, 2011;19:317–8.
- Mustian KM, Palesh OG, Sprod LK, et al., YOCAS©® Yoga significantly improves sleep, fatigue and quality of life: A URCC CCOP randomized, controlled clinical trial among 410 cancer survivors, J Clin Oncol, 2010;28:639.
- Mustian KM, Palesh OG, Sprod LK, et al., YOCAS©® Yoga improves insomnia among 410 cancer survivors, Int J Behav Med, 2010;17:209.
- Chandwani KD, Thornton B, Perkins GH, et al., Yoga improves quality of life and benefit finding in women undergoing radiotherapy for breast cancer, J Soc Integr Oncol, 2010;8:43–55.
- Cadmus-Bertram L, Littman AJ, Ulrich CM, et al., Predictors of adherence to a 26-week viniyoga intervention among posttreatment breast cancer survivors, J Altern Complement Med, 2013;19:751–8.
- Dhruva A, Miaskowski C, Abrams D, et al., Yoga breathing for cancer chemotherapy-associated symptoms and quality of life: results of a pilot randomized controlled trial, J Altern Complement Med, 2012;18:473–9.
- Drake CL, Roehrs T, Roth T, Insomnia causes, consequences, and therapeutics: an overview, Depress Anxiety, 2003;18:163–76.
- Ryan JL, Carroll JK, Ryan EP, et al., Mechanisms of cancer-related fatigue, The Oncologist, 2007;12:22–34.
- Takahashi JS, Hong HK, Ko CH, McDearmon EL, The genetics of mammalian circadian order and disorder: implications for physiology and disease, Nat Rev Genet, 2008;9:764–75.
- Ko CH, Takahashi JS, Molecular components of the mammalian circadian clock, Hum Mol Genet, 2006;15 Spec No 2:R271-7.
- Kalsbeek A, SCN outputs and the hypothalamic balance of life, J Biol Rhythms, 2006;21:458–69.
- Petersen AM, Pedersen BK, Petersen AMW, The role of IL-6 in mediating the anti-inflammatory effects of exercise, J Physiol Pharmacol, 2006;57(Suppl. 10):43–51.
- Rao A, Nagendra HR, Raghuram N, et al., Influence of yoga on postoperative outcomes and wound healing in early operable breast cancer patients undergoing surgery, Int J Yoga, 2008;1:33–41.
- Rao RM, Nagendra HR, Raguhuram N, et al., Influence of yoga on mood states, distress, quality of life, and immune outcomes in early stage breast cancer patients undergoing surgery, Int J Yoga, 2008;1:11–9.
- Vadiraja HS, Raghavendra RM, Nagarathna R, et al., Effects of a yoga program on cortisol rhythm and mood states in early breast cancer patients undergoing adjuvant radiotherapy: a randomized controlled trial, Integr Cancer Ther, 2009;8:37–46.
- Kirshbaum MN, A review of the benefits of whole body exercise during and after treatment for breast cancer, J Clin Nurs, 2007;16:104–21.
- McArdle W, Katch F, Katch V, Exercise Physiology: Energy, Nutrition, and Human Performance, Philadelphia, PA: Lippincott, Williams and Wilkins, 2007.
- Kubitz KA, Landers DM, Petruzzello SJ, Han M, The effects of acute and chronic exercise on sleep: A meta-analytic review, Sports Medicine, 1996;21:277–91.
- Sherrill DL, Kotchou K, Quan SF, Association of physical activity and human sleep disorders, Arch Intern Med, 1998;158:1894–8.
- Youngstedt SD, Effects of exercise on sleep, Clin Sports Med, 2005;24:355–65, xi.
- Driver HS, Taylor SR, Exercise and sleep, Sleep Med Rev, 2000;4:387–402.
- Field T, Yoga clinical research review, Complement Ther Clin Pract, 2011;17:1–8.
- Ross A, Thomas S, The health benefits of yoga and exercise: a review of comparison studies, J Altern Complement Med, 2010;16:3–12.
- Lipton L, Using Yoga to Treat Disease: An Evidence-Based Review, JAAPA, 2008;21:34–6, 38, 41.
- Innes KE, Bourguignon C, Taylor AG, Risk indices associated with the insulin resistance syndrome, cardiovascular disease, and possible protection with yoga: a systematic review, J Am Board Fam Pract, 2005;18:491–519.
- Jayasinghe SR, Yoga in cardiac health, Eur J Cardiovasc Prev Rehabil, 2004;11:369–75.
- Raub JA, Psychophysiologic effects of Hatha Yoga on musculoskeletal and cardiopulmonary function: a literature review, J Altern Complement Med, 2002;8:797–812.
- Balasubramaniam M, Telles S, Doraiswamy PM, Yoga on our minds: a systematic review of yoga for neuropsychiatric disorders, Front Psychiatry, 2012;3:117.
- Buffart LM, van Uffelen JG, Riphagen II, et al., Physical and psychosocial benefits of yoga in cancer patients and survivors; a systematic review and meta-analysis of randomized controlled trials, BMC Cancer, 2012;12:559.
- Cramer H, Lauche R, Langhorst J, Dobos G, Yoga for depression: a systematic review and meta-analysis, Depress Anxiety, 2013;30:1068–83.
- Duncan MD, Leis A, Taylor-Brown JW, Impact and outcomes of an Iyengar yoga program in a cancer centre, Curr Oncol, 2008;15(Suppl. 2):s109.es72–8.
- Joseph CD, Psychological supportive therapy for cancer patients, Indian J Cancer, 1983;20:268–70.
- Rosenbaum E, Gautier H, Fobair P, et al., Cancer supportive care, improving the quality of life for cancer patients, A program evaluation report, Support Care Cancer, 2004;12:293–301.
- Speed-Andrews AE, Stevinson C, Belanger LJ, et al., Pilot evaluation of an Iyengar yoga program for breast cancer survivors, Cancer Nursing, 2010;33:369–81.
- Bower JE, Garet D, Sternlieb B, et al., Yoga for persistent fatigue in breast cancer survivors: a randomized controlled trial, Cancer, 2012;118:3766–75.
- Cadmus-Bertram L, Littman AJ, Ulrich CM, et al., Predictors of adherence to a 26-week viniyoga intervention among posttreatment breast cancer survivors, J Altern Complement Med, (New York, NY), 2013;19:751–8.
- Chandwani KD, Perkins G, Nagendra HR, et al., Randomized, controlled trial of yoga in women with breast cancer undergoing radiotherapy, J Clin Oncol, 2014;32:1058–65.
- Mustian KM, Sprod LK, Janelsins M, et al., Multicenter, randomized controlled trial of yoga for sleep quality among cancer survivors, J Clin Oncol, 2013;31:3233–41.
- Ulger O, Yagli NV, Effects of yoga on the quality of life in cancer patients, Complement Ther Clin Pract, 2010;16:60–3.
- Mustian KM, Sprod LK, Janelsins M, et al., Exercise recommendations for cancer-related fatigue, cognitive impairment, sleep problems, depression, pain, anxiety, and physical dysfunction: a review, Oncol Hematol Rev, 2012;8:81–8.
- Schmitz KH, Courneya KS, Matthews C, et al., American College of Sports Medicine roundtable on exercise guidelines for cancer survivors, Med Sci Sports Exerc, 2010;42:1409–26.