Why Yoga Works

Introduction

There is an abundance of research showing yoga’s positive impact on chronic pain, brain health, hormone regulation, PTSD, anxiety, depression, bone density and much more. Get concise summaries and links to original research here:

• How Yoga Supports Health & Physiology

• Research Summaries by Subject

In this lesson, we’re focused on how yoga impacts gene expression and stress. But in real life, there’s no clear dividing line between how yoga impacts conditions such as chronic pain, and how it impacts stress. That is, if we suffer from PTSD, anxiety, MS or fibromyalgia, we will also be suffering from some degree of stress that may be an outcome of the condition, but also an exacerbating factor.

Attempts to separate yoga’s impact on one or the other is simply researchers’ efforts to pull things apart for greater understanding about how yoga impacts people, and what leads to healing. But let’s not lose sight of the fact that the body is a holistic system that defies such rigid lines of delineation. The entire collection of research can help us to get a grasp on just how powerful yoga can be. The stunning results from the Benson-Henry research described in the next section on gene expression speak to this in a profound way.

Regulating the Nervous System is Arguably the Most Fundamental Action We Can Take for Maximum Positive ImpactHow important is it that we learn to heal and regulate our nervous system? Consider this: who would you rather have babysitting your child? Someone who is tense and anxious and has trouble staying focused, or someone who is focused, calm, and happy? Which surgeon would you prefer operate on your brain or heart? One who is tense and anxious and sleep deprived, or someone who is focused, calm, and well rested? So, how important is it that we learn to heal and regulate our nervous system? The answer is obvious isn’t it? Learning to regulate our nervous system is every bit as important as exercising our body. In context to our relationships it is arguably far more important. – Max Strom, email newsletter August 11, 2014

Epigenetics: Yoga’s Impact on Gene Expression

The following comments by Harvard Medical School editors are referring to research conducted by the Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital in 2013.

Eliciting the Relaxation Response Caused Genes to Turn On & Off That Have Extensive Positive Impacts on Health & Well-Being

Skeptics have long believed that meditation and other stress reduction techniques are nice but ineffectual practices that do little for you. Nothing could be further from the truth — and now we have the science to prove it… Exciting new research… suggests that the simple act of eliciting the relaxation response… temporarily changes the activity of certain genes… it switches off genes associated with chronic inflammatory responses. Many experts believe these inflammatory responses stress the body, possibly contributing to a host of chronic ailments, such as heart disease, inflammatory bowel disease, and diabetes. At the same time, it switches on genes linked with a variety of functions: the use of energy in the body, the release of insulin (which helps regulate blood sugar), the maintenance of telomeres (protective end-caps on our chromosomes that erode with age until a cell dies), and the functions of tiny cellular powerhouses called mitochondria… This information was prepared by the editors of the Harvard Health Publications division of Harvard Medical School. It is excerpted from our Special Health Report: Stress Management. – Harvard Medical School link

Findings and implications:

1. Chronic stress is known to both cause and exacerbate disease, and can lead to other problems such as anxiety or depression.

2. A balanced nervous system is key to positively managing stress. Eliciting the relaxation response balances the nervous system and brings a cascade of positive health effects.

3. The Benson-Henry research shows that the relaxation response is also impacting the body in another, even deeper way. The relaxation response affects us at the deepest level of physical life, the cellular level, impacting which genes are turned on and off (called epigenetics). This sets off a series of powerful activities that relate to health including the health of telomeres and mitochondria.

4. Chronic inflammation overwhelms the immune system and causes additional symptoms. Chronic inflammation is on a short list of underlying causes of imbalance and disease. The Benson-Henry research shows that the relaxation response switches off genes associated with chronic inflammatory responses.

The information above is from the lesson, Epigenetics & Lifestyle. Please see that lesson for more detail on the fascinating and important subject of epigenetics, a science that debunks the “genetic blueprint” ideology and empowers people to heal.

Yoga’s Impact on the Nervous System

Yoga’s impact on the nervous system is a fundamental reason for its effectiveness in so many situations.

You Can’t Just Tell Yourself to Relax

Of course when you are stressed out, you can’t just tell yourself to relax. (I remember when I was suffering terribly from chronic stress, a therapist told me to “stop worrying.” I said, “Are you kidding?” and, duh, never went back.) But this is where yoga performs so brilliantly. – Nina Zolotow, Yoga for Times of Change, The Relaxation Response and Yoga link

Yoga Triggers the Relaxation Response

Many yoga practices trigger the Relaxation Response.

Examples include:

• Calming Breath Practices

• Mindfulness and Meditation

• Restorative Yoga

• Inversions

• Conscious Relaxation including such practices as Yoga Nidra and Guided Visualization

• Mindful Movement

What Is Relaxation?The antidote to stress is relaxation. To relax is to rest deeply. This rest is different from sleep. Deep states of sleep include periods of dreaming which increase muscular tension, as well as other physiological signs of tension. Relaxation is a state in which there is no movement, no effort, and the brain is quiet. — Judith Lasater

Yoga Cultivates Interoception Which Improves Stress Resilience

The nervous system includes the brain. How the brain interprets signals is integral to how we experience stress. One of the many experiences we have that involves the brain is our sensing of the inner body, called interoceptive awareness.

Research shows that interoception is directly related to stress resilience.

Thus, the inner attention and awareness that is central to yoga and cultivates the skill of interoception is another way to explain how yoga impacts our nervous system and experience of stress.

This research suggests that the modulation of brain systems that process interoceptive information may be necessary to effectively manage life stress. … Results showed that participants in the low resilience group reported decreased interoceptive awareness compared to those who endorsed medium or high resilience to stress… The study’s authors suggest that a decreased awareness of bodily signals (interoceptive awareness) may leave individuals with lower levels of resilience and greater susceptibility to stress due to a limited capacity to accurately monitor bodily states or predict future needs. This means that adults with attenuated body awareness may be more likely to interpret life events as stressful and less able to enact effective coping strategies. – B Grace Bullock PhD, YogaUOnline, What Your Body Tells You Can Protect You From Stress, Study Suggests link

Yoga Increases & Sustains Vagal Tone

In a closely related point, some yoga practices indirectly stimulate the vagus nerve and help to sustain vagal tone, encouraging a healthy shift from the Fight or Flight Response to the Relaxation Response. Examples include:

1. Brahmari Pranayama

2. Ujjayi Pranayama

3. Nadi Shodhana Pranayama

4. Chanting

5. Lovingkindness Meditation

Diaphragmatic Breathing Activates Relaxation Response

Diaphragmatic breathing activates the relax-and-digest response by stimulating the primary mediator of the parasympathetic nervous system, the vagus nerve… As you develop the skill of breathing from the diaphragm in the course of your daily activities, you will begin to experience your breath as a barometer for the nervous system. As long as you are breathing deeply and from the diaphragm, you will find that you can access a feeling of calm and balance even when you are confronted with an unpleasant situation. And you will also notice that if you allow your breath to become shallow by breathing from your chest, anxiety creeps in, your muscles tighten, and your mind begins to race and spin. – Carrie Demers, MD, medical director for health and healing at the Himalayan Institute, How to Change Your Stress Response link

Many Benefits from Breath Practices

Vagal tone increases during exhalation. By slowing down our respiration through deep, intentional breathing and elongating our exhalation, we can activate the vagal brake and elicit the relaxation response almost immediately. Once this response is initiated and the parasympathetic nervous system (PNS) is dominant, our brains cease to be governed by the limbic system and fear circuitry that limits our capacity to effectively think, plan, reason and respond to others. This means that we are no longer subject to a narrow range of defensive or escape behaviors. Through intentionally deepening the breath and prolonging exhalation, we access not only the relaxation response, but also the capacity to be mindfully present in relationship. – B. Grace Bullock PhD, Yoga International, Tapping Into the Power of the Vagus Nerve link

Yoga Increases GABA Levels

A momentous event in the world of verifiable evidence came in 2010, when Chris Streeter MD, associate professor of psychiatry at Boston University School of Medicine and other researchers published findings from a randomized controlled study showing that yoga increases GABA levels.

GABA is a neurotransmitter that sends messages through the nervous system, and is involved in regulating communication between brain cells. It plays an important role in behavior, cognition, and the body’s response to stress.

• Research suggests that GABA helps to control fear and anxiety.

• Conversely, low levels of GABA in the brain have been linked to schizophrenia, depression, anxiety, and sleep disorders. (Everyday Health)

• Anti-anxiety medications work by encouraging the release of GABA.

• And GABA is what alcohol mimics, by temporarily binding to the same chemical receptors. (Psychology Today)

Yoga Increases GABA Levels

Studies by Streeter and colleagues demonstrate that regular practice of gentle yoga, but not walking, releases a chemical called GABA in the thalamus…  GABA was shown to be significantly higher in the brains of those subjects who had been doing yoga. The study also compared GABA levels directly before and after an hour of yoga, and showed a 27% increase! – Rachael Grazioplene, Psychology Today, This is Your Brain on Yoga link

In Scientific Research: How Yoga Works, Angela Wilson highlighted these additional study results from the GABA study:

• Chris Streeter’s study hypothesized that yoga works to increase the body’s ability to successfully respond to stress by increasing vagal tone and thereby regulating the nervous system.

• Ujjayi Pranayama was shown to increase the relaxation response and heart rate variability (a function of stress resilience).

• Chanting Om out loud increased vagal tone and the relaxation response more than chanting it silently.

Yoga for better mental health

April 29, 2024

With its emphasis on breathing practices and meditation — both of which help calm and center the mind — it's hardly surprising that yoga also brings mental benefits, such as reduced anxiety and depression. What may be more surprising is that it actually makes your brain work better.

According to an Article in Harvard Medical School

Yoga for better mental health

April 29, 2024

A sharper brain

"When you lift weights, your muscles get stronger and bigger. When you do yoga, your brain cells develop new connections, and changes occur in brain structure as well as function, resulting in improved cognitive skills such as learning and memory. Yoga strengthens parts of the brain that play a key role in memory, attention, awareness, thought, and language. Think of it as weightlifting for the brain.

Studies using MRI scans and other brain imaging technology have shown that people who regularly did yoga had a thicker cerebral cortex (the area of the brain responsible for information processing) and hippocampus (the area of the brain involved in learning and memory) compared with nonpractitioners. These areas of the brain typically shrink as you age, but the older yoga practitioners showed less shrinkage than those who did no yoga. This suggests that yoga may counteract age-related declines in memory and other cognitive skills.

Research also shows that yoga and meditation may improve executive functions, such as reasoning, decision-making, memory, learning, reaction time, and accuracy on tests of mental acuity.

Improved mood

All exercise can boost your mood by lowering levels of stress hormones, increasing the production of feel-good chemicals known as endorphins, and bringing more oxygenated blood to your brain. But yoga may have additional benefits. It can affect mood by elevating levels of a brain chemical called gamma-aminobutyric acid (GABA), which is associated with better mood and decreased anxiety.

Meditation also reduces activity in the limbic system — the part of the brain dedicated to emotions. As your emotional reactivity diminishes, you have a more tempered response when faced with stressful situations.

Drugs and talk therapy have traditionally been the go-to remedies for depression and anxiety. But complementary approaches such as yoga also help, and yoga stacks up well when compared with other complementary therapies.

A review of 15 studies, published in the journal Aging and Mental Health, looked at the effect of a variety of relaxation techniques on depression and anxiety in older adults. In addition to yoga, interventions included massage therapy, progressive muscle relaxation, stress management, and listening to music. While all the techniques provided some benefit, yoga and music were the most effective for both depression and anxiety. And yoga appeared to provide the longest-lasting effect.

A number of small studies have found that yoga can help with post-traumatic stress disorder (PTSD). It is not used by itself, but as an add-on treatment to help reduce intrusive memories and emotional arousal and to produce calmer, steadier breathing. Deep, slow breathing is associated with calmer states because it helps activate the parasympathetic nervous system."

Discover the healing power of Yoga withIntermediate Yoga, a Special Health Report from Harvard Medical School.

practicing yoga

Image: © FatCamera/Getty Images

More Ways That Yoga Relieves Stress

In addition to impacting the nervous system and increasing GABA levels, yoga helps to relieve stress in the following ways.

1. Stress causes a rapid breath rate and yoga can slow the breath down.

2. Slower, diaphragmatic breathing helps to balance the pH level of the blood.

3. Releasing tension in the psoas is related to relieving stress.

4. The stress response includes not only such activities as increased heart rate, but also particular muscular contractions. Yoga practices help to release muscular tension induced by such a stress response.

Decrease Rapid Breathing Caused by Stress

Chronic stress can disrupt the normal balance between your brain and your respiratory system by causing unhealthy breathing patterns. That’s because when you are stressed and triggering your fight-or-flight response, your brain reacts by stimulating your respiratory system to take in more oxygen to prepare you for action. But if you’re chronically just “feeling” stressed, you don’t actually need to take action, though you’ll still be breathing as if you do. By using yoga stress management techniques and spending more time in a state of relaxation, you can rebalance your brain’s input to your respiratory system and re-establish healthier, more appropriate breathing patterns. – Baxter Bell MD, YogaUOnline, Your Respiratory System is More than Just a Pair of Lungs link

Slower Breathing Balances Blood pH Level

In stressful times, we typically breathe too rapidly. This leads to a buildup of oxygen in the bloodstream and a corresponding decrease in the relative amount of carbon dioxide, which in turn upsets the ideal acid-alkaline balance—the pH level—of the blood. This condition, known as respiratory alkalosis, can result in muscle twitching, nausea, irritability, lightheadedness, confusion, and anxiety. In contrast, slowing the breath raises the carbon dioxide level in the blood, which nudges the pH level back to a less alkaline state. As the blood’s pH changes, the parasympathetic nervous system calms us in a variety of ways, including telling the vagus nerve to secrete acetylcholine, a substance that lowers the heart rate. – Richard RosenUndoing the Stress ResponsePart of the stress response hardwired into our nervous system is the contraction of the major flexors of the torso—somewhat like the response of a caterpillar if you poke it with a twig. A verbal jab from a co-worker, the close call on the freeway, a long-standing argument with your spouse, free-floating anxiety—all of these elicit a contraction in the flexors. This is the tightening in the gut, the hunching of the shoulders, the sinking of the heart. As with all responses to stress, the problem is that the response becomes habitual, resulting in chronic tension and contraction, which we then experience as our “normal” state. Our yoga practice is an opportunity to undo this chronic tension, and establish a deep and abiding sense of harmony in the body and mind. – Sandra Anderson, Yoga International, Release Tension in the Psoas link

Research on Yoga’s Impact

See Research on the Impact of Yoga; Stress, Immunity, Genes, Cells for summaries and links to research demonstrating these outcomes:

1. Positively affected physiological measures of stress including cortisol, blood pressure, heart rate, heart rate variability, fasting blood glucose, and cholesterol (2017)

2. Significant shift in autonomic balance towards vagal dominance; significant reduction in stress, anger, depression, and anxiety; reduction in heart rate and blood pressure; reduction in irregular heartbeat (AFib); and improvements in emotional processing (2017)

3. Mindfulness reduced cortisol and anxiety (2012)

4. Mindfulness reduced stress and anxiety in the moment as well as after (2013)

5. Decreased cortisol (a hormone associated with stress) in people new to yoga (2007)

6. Stress levels and burnout consistently reduced among those who practice yoga and meditation (2019)

7. Positive effects on stress reduction in healthy populations (2020)

8. Decreased blood pressure, heart rate, and expression of stress markers such as cortisol and cytokines (2015)

9. Progressive relaxation, guided imagery and a breathing practice were each effective in promoting relaxation; progressive relaxation and guided imagery were effective both psychologically and physiologically (2021)

10. Alternate nostril breathing improved performance in a test of sustained attention, while also reducing blood pressure during the test, implying a reduction in sympathetic nervous activation as well (2017)

11. After 6 weeks of 21 minutes each day (of a breathing and meditation technique), participants reported lower levels of stress and higher levels of well-being using a scale comparing against baseline (2017)

12. Family caregivers experienced a significant reduction in stress, and reduced risk of cardiovascular disease & insulin-related disease (2022)

13. Improvements in well-being (2017)

14. Positive effect on mental health and stress in the workplace, no negative effects (2019)

15. Improved physical capabilities and quality of life measures in healthy seniors (2006)

16. Reduced need for healthcare services by 43% (2015)

See Research on the Impact of Yoga – Brain, Nervous System for summaries and links to research demonstrating these outcomes:

1. Improved reaction time, accuracy, memory (2012)

2. Cognitive function improved in older population (2014)

3. Cognitive function & memory improved in young adults (2019)

4. Increased capacity to dual-task, decreased risk of errors & falling (2016)

5. Alternate nostril breathing reduced blood pressure & improved performance that required hand-eye coordination & focus (2014)

6. Alternative nostril breathing improved performance in a test of sustained attention, while also reducing blood pressure during the test, implying a reduction in sympathetic nervous activation as well (2017)

7. Yoga induced the relaxation response, with alpha/theta brain waves (1977)

8. Yoga changes brains (2019)

9. Elevated GABA levels (2007)

10. Meditation causes widespread changes in brain (2015)

11. Even among novice meditators, meditation produced brain wave changes, plus a small reduction in blood pressure among those without blood pressure issues (2015)

12. Yoga affected brain structure (2018)

13. Thicker prefrontal cortex (2017)

14. Smaller volume of brain region tied to negative emotions (2018)

15. Meditation altered brain & immune function (2003)

16. Meditation rebuilt brain’s gray matter (2011)

17. Brains experience different structural changes based on different meditation techniques (2017)

18. Ashtanga primary series changed brain activity (2020)

19. Targeted meditation increased compassion & changed brain (2013)

20. Improvements in frequency, duration, and pain intensity of tension headaches (2019)

21. Reduced symptoms of tension headaches (2020)

22. Yoga Therapy effective for headaches (2015)

23. Intensity of stress associated with tension headaches (2015)

24. Relaxation & biofeedback lessened headache and migraine duration & frequency

25. Epilepsy patients: Improvements in seizure duration & frequency (2015)

26. Meditation reduced seizure frequency in epilepsy patients (2006)

27. Reduced seizure frequency & duration in epilepsy patients (2001)

28. Improved parasympathetic parameters & decreased seizure frequency in epileptic patients compared to exercise control group (2008)

29. Improvements in physical capabilities and quality of life in MS patients (2014)

30. Multiple studies reported improvement in mental, physical & quality of life factors with MS patients (2014)

31. Review of 7 randomized control trials (RCTs) with MS patients (2014)

32. Improved quality of life for people with neurological disorders: Improved balance, strength, mobility, mood; reduced pain, tremors; more (2017)