Yoga for a Healthy Heart - A New Research Review Charts the Benefits of Yoga on Markers of Heart Health
According to a new, comprehensive review of yoga research, reviews, and meta-analyses published in Complementary Therapies in Clinical Practice, the field of yoga research has grown exponentially in the past 5 years, with nearly 200 studies being published annually. As we continue to gain evidence into how yogic principles and practices can be used to maintain and restore health, we will be more equipped to use these technologies in our daily lives, and incorporate them into mainstream health care.
In Part I of this article we examined current trends in yoga research, as well as who is practicing yoga, how, its effectiveness for relieving symptoms of stress and psychological illness, and its overall safety for the general public, and for pregnant women. The same study offered an overview of the research on the benefits of yoga for a breadth of physical ailments and illnesses. In this article, we explore the benefits of yoga on markers of heart health.
Yoga and Heart Health
As we reviewed in Part I, one of the greatest known benefits of yoga is its potential to relieve stress. Decades of research points to chronic stress as a key risk factor for physical and psychological illness. When it comes to the heart, stress is linked to the onset and progression of most cardiovascular conditions such as heart attack and stroke, as well as precursors of heart disease like hypertension, high cholesterol, and Type II Diabetes.
Yoga and Prehypertension
Hypertension, also known as high blood pressure, is one of the leading causes of heart attack, stroke, and premature death. Hypertension has reached epidemic proportions in the United States, with approximately 20.1% of Americans being diagnosed with the disease in 2011-2012. Prehypertension is a condition characterized by elevated blood pressure (systolic BP 120-139 and diastolic BP 80-89). It is often the precursor to full blown hypertension, and is the target of aggressive intervention.
In a randomized controlled trial comparing yoga to lifestyle modification (healthy diet, exercise etc.), and yoga plus lifestyle modification in adults with prehypertension, participants in the yoga plus lifestyle group showed significant decreases in systolic blood pressure (BP) compared to the yoga only group, which experienced a significant decrease in diastolic BP. This suggests that yoga may contribute to lifestyle modifications aimed at reducing cardiovascular disease risk.
Yoga for Hypertension
Considerably more research has addressed the effects of yoga interventions on hypertension (high BP). A systematic review of 17, randomized controlled trials found 11 studies that linked regular yoga practice to significantly greater reductions in systolic BP compared to pharmacotherapy, breath awareness, health education, no treatment, or usual care. Conversely, in 5 trials, yoga was reported as having no effect on systolic BP compared to dietary modification, enhanced usual care, relaxation or physical exercise.
Of these studies, 8 trials showed that yoga was linked to greater reductions in diastolic BP when compared to pharmacotherapy, no treatment or usual care, however the other 8 studies reported no effects of diastolic BP relative to control conditions. As such, the evidence of yoga as an ancillary treatment for hypertension is encouraging, but inconclusive.
Yoga and Cholesterol
High cholesterol is also considered a significant risk factor for, and corollary of heart disease. Similar to the findings on yoga for hypertension, the scientific evidence is encouraging, but mixed.
In a systematic review and meta-analysis of 44, randomized controlled trials that included over 3,100 participants, those participating in a yoga intervention showed improved HDL, VLCI, triglycerides and insulin resistance - all markers of cholesterol - compared to usual care or no treatment. Yoga participants also showed superior declines in LDL.
Results from this meta-analysis also revealed improved systolic and diastolic BP, and lowered heart and respiratory rates, as well as decreased waist circumference in the yoga groups compared to no intervention controls. Similarly, a review of 37, RCTs showed that yoga participants had significantly better results on measures of HDL, LDL, total cholesterol, triglycerides, systolic BP and heart rate compared to non-exercise controls. While this is encouraging, authors of the study suggest interpreting results with caution due to the lack of high-quality research in some cases.
We’ve long known that yoga is mind-body “medicine”, affecting individuals holistically rather than changing discrete elements of their anatomy, physiology, or mind. Although there is considerably more to learn via high quality yoga studies, this review suggests that a regular yoga practice may have a positive impact on some markers of heart health.
B Grace Bullock, PhD, E-RYT 500 is a psychologist, research scientist, educator, yoga and mindfulness expert and author of Mindful Relationships: Seven Skills for Success - Integrating the Science of Mind, Body and Brain. Her mission is to reduce stress, increase health and well-being and improve the quality of relationships. She offers classes, workshops, writing and research that combine the wisdom of applied neuroscience, psychophysiology, psychology and contemplative science and practice. Her goal is to empower individuals, groups, leaders and organizations to reduce chronic stress and increase awareness, attention, compassion, mindfulness and effective communication to strengthen relationships, release dysfunctional patterns and unlock new and healthy ways of being. Dr. Bullock is also the Founding Director and Principal Consultant of the International Science & Education Alliance, an organization devoted to exceptional research, program evaluation, assessment design, strategic planning and capacity building to support equity, programmatic diversity and scientific integrity, and promote effective leadership, decision-making and social change. Bullock is a Certified Viniyoga Therapist and Faculty at the Integrated Health Yoga Therapy (IHYT) Training program. She is the former Senior Research Scientist at the Mind & Life Institute and former Editor-in-Chief of the International Journal of Yoga Therapy. For more information see www.bgracebullock.com.
Field, T. (2016). Yoga Research Review. Complementary Therapies In Clinical Practice, 24, 145-161.