A review of 11 randomised clinical trials (RCTs) and 6 non- RCTs found consistent support from the efficacy of yoga to improve mental health outcomes (such as distress, mood and anxiety) during cancer treatment.
Some research found improvements in sleep, fatigue, and quality of life during treatment. A review of 9 RCTs and 6 non-randomized studies of yoga use by cancer survivors suggests physical and psychosocial benefits. Preliminary findings show potential relief from fatigue, dyspnea, gastrointestinal issues, menopausal symptoms, pain severity, and improvements in respiratory function, heart rate, and HRV, as well as sleep-related benefits, emotional well-being, vigor, stress, and cognitive functioning.
Neuroscience and psychology show that the default state of the human brain is mind wandering—ruminating about the past or thinking about the future. Yoga and meditation shift attention to the interoceptive neural network by directing attention to present-moment interoceptive bodily sensations such as breath. In other words, we notice how we are feeling when we get triggered, making it more likely we will make different choices, such as stop and take a deep breath, think and then respond, rather than just react.
The autonomic nervous system continuously makes metabolic and vascular adjustments to try to maintain homeostasis (and keep us alive). Conscious awareness of bodily states (through interoception) alerts our mind to make changes in the body or our environment to maintain homeostasis.
Good emotional awareness means that someone detects bodily signals and can clearly differentiate how each emotion feels. That awareness enables that person to alter emotions or situations to maintain, increase, or decrease an emotion.
- Practicing yoga regularly can support change in the way the mind and body function: Inhibiting cognitive, emotional, and behavioral stress responses (such as negative self-appraisal, emotional reactivity, and rumination)
- Inhibiting autonomic stress responses (such as vasopulmonary constriction, inflammation, and muscle tension and pain)
- Facilitating viscerosomatic processing of sensory— motor signals
Another theoretical mechanism of yoga effects is that breath regulation (pranayama) during yoga practices improves vagal nerve tone. The vagus nerve contains the main bidirectional perceptual pathway of the parasympathetic nervous system (PNS). Practicing yoga shifts regulatory systems toward optimal homeostasis, reducing allostatic load and correcting underactivity of the PNS and γ-aminobutyric acid systems.
Allostatic load is the cost to the body of maintaining stability during reactions to chronic stress (such as high blood pressure and elevated heart rate). In this way, yoga supports the functioning of the autonomic nervous, neuroendocrine, hypothalamic-pituitary- adrenal axis, cardiovascular, metabolic, and immune systems and influences emotional states and thought processes.
Yoga interventions are noninvasive, low cost, and can be adapted for people who have functional or other impairments.
References:
Cancer: In Depth. National Center for Complementary and Integrative Health. 2017 [cited 2017 Dec 13]. Available from: nccih.nih.gov/health/cancer/complementary-integrative-research. Accessed March 29, 2018.
Desikachar TKV. The Heart of Yoga: Developing a Personal Practice. Revised edit. Rochester, VT: Inner Traditions; 1999:244.
Clarke T, Black L, Stussman B, Barnes P, Nahin R. Trends in the use of complementary health approaches among adults: United States, 2002—2012. National health statistics reports; no 79. Hyattsville, MD: Stussman. 2015. Hyattsville, MD: