Yoga (from Sanskrit “yoke” or “union”) is a darśana (from Sanskrit “to see”), it’s traditionally been a path toward enlightenment or freedom from karma or the illusions of suffering. Yoga originated more than 5,000 years ago in the Indus-Sarasvati civilization1.
Yoga, in sickness and health
In their recent review in the journal Mindfulness, Pascoe and colleagues (2021) note research showing different forms of yoga increase mindfulness and spiritual well-being, alleviate symptoms of anxiety, stress, pain, and depression in clinical populations, and decrease stress and improve well-being in non-clinical groups. There are many different types of yoga, each integrating different practices and approaches, complicating research.
The researchers included 22 studies culled from multiple databases to identify a broad array of articles. They did not assess the methodology of studies, as the goal of this narrative review was to capture the state of the current literature in the field. From these studies, they identified common proposed mechanisms for yoga’s physiological effects.
13 areas where yoga may affect psychobiological functions
- Interoception: Our ability to perceive the internal state of our bodies is a key factor in health, and for having a healthy relationship with our own bodies, especially in trauma. Mindful interoceptive awareness has been associated with better pain control, along with other benefits. Yoga practice trains people to build interoceptive awareness, as shown in smaller studies. However, more research is needed to better understand how yoga, interception, and health are related.
- Self-compassion: When we are suffering, being self-critical, experiencing feelings of failure and insecurity, self-compassion allows people to respond with kindness to one’s own state of mind, helping to ground us and foster soothing, positive self-parenting, helpful for well-being. This review found several studies connecting different forms of yoga with increased self-compassion. Research suggests that facing fears of compassion may help people make progress.
- Emotional regulation: Smoothly managing challenging emotional states is considered a core self-regulatory skill, and part of overall good personality functioning, working with reflective function (mentalization) and executive skills to help us best deploy our resources in times of stress and repose. Authors found no large studies of emotional regulation and yoga, but noted two smaller studies showing improvements in this area in adolescents and yoga practitioners.
- Avoidance/Exposure: Avoidance is a cardinal feature of maladaptive responses to trauma, which, while preventing triggering, leaves people vulnerable to distress when triggers cannot be avoided, and preventing adaptation, or desensitization, to traumatic reminders. Given that many reminders are out of one’s control, internal or in the world, learning to attend to distressing cues without being overwhelmed or needed to steer clear is important for recovery2.
- Rumination: Excessive attention to unpleasant thoughts, memories, experiences or sensations is associated with less robust coping with trauma and distress. To an extent, the ability to mull over thoughts, to make sense of them, cope with emotions as noted above, and move on, is helpful and associated with resilience. Self-compassion has been shown to decrease excessive rumination. The literature on yoga and excessive rumination is inconclusive but a small, controlled study suggests there are benefits for women with depression.
- Meta-cognition: Related to emotion regulation, executive function and, mentalization—the ability to accurately sense others’ inner states—meta-cognition refers to being able to partially detach from thoughts and feelings, to “let go” of distress and hold suffering more lightly, as well as to reflect upon such experiences mentally, make sense of them, and keep them in context. Yoga has been shown to increase meta-cognition around physical sensations, notably pain. There is no specific research on meta-cognition with yoga, but one study of MSBR which included hatha yoga found increased meta-cognition in depressed patients.
- Attention and Memory: Improving cognitive capacity can help to facilitate positive changes, contributing to good executive function in the deployment of resources. Being able to focus on and remember plans and goals helps in changing habits, making better choices when one is unwell, and sustaining healthy routines. Authors report that multiple studies show improvements in working memory, attention, and inhibitory control with yoga. Less robust findings suggest that yoga may improve some aspects of memory, due to factors which may include improvements in sleep, neural connectivity, and mood.
- Blood Pressure: Elevated blood pressure, when more severe, results in hypertension and requires medical treatment. Less severe elevated blood pressure is associated with high stress, and reductions in blood pressure with relaxation response and better health outcomes. Different forms of yoga have been shown in numerous studies to have a limited impact in reducing blood pressure through different mechanisms, including mindfulness practice and importantly, aerobic exercise.
- Heart Rate: As with high blood pressure, increased heart rate is associated with acute and chronic stress reactions, and also positive excitement and arousal. Similarly, several studies have found that yoga modestly decreases heart rate.
- Heart Rate Variability: Perhaps more than blood pressure or heart rate per se, heart rate variability (HRV) has been shown to be a marker of health and illness3. Numerous studies of yoga and HRV have found beneficial effects on measures of HRV associated with increased parasympathetic activity via vagal effects and improvements in cardiac parameters as reflected in detailed HRV analysis (i.e. increases in low-frequency HRV are thought to connect with greater parasympathetic response), and with benefits over and above exercise alone.