Harvard Medical School Publication

Harvard Health Publishing Article on June 23, 2024

With its focus on breathing and meditation practices (both help calm and center the mind), it’s no surprise that yoga also provides mental benefits, such as reducing anxiety and depression. What may be more surprising is that it actually makes your brain function better.

A Sharper Brain

When you lift weights, your muscles become stronger and larger. When you practice yoga, your brain cells develop new connections, and changes occur in the brain's structure and function, resulting in improved cognitive abilities such as learning and memory. Yoga strengthens parts of the brain that play a key role in memory, attention, awareness, thinking, and language. Think of it as weightlifting for the brain.

Studies using magnetic resonance imaging (MRI) scans and other brain imaging technologies have shown that people who practice yoga regularly have a thicker cerebral cortex (the area of the brain responsible for processing information) and a larger hippocampus (the area of the brain involved in learning and memory) compared to non-practitioners. These areas of the brain typically shrink as you age, but older yoga practitioners showed less shrinkage than those who did not practice yoga. This suggests that yoga may counteract age-related decline in memory and other cognitive abilities.

Research also shows that yoga and meditation can improve executive functions such as reasoning, decision-making, memory, learning, reaction time, and accuracy in mental sharpness tests.

Mood Improvement

Exercise of any kind can improve your mood by lowering stress hormone levels, increasing the production of feel-good chemicals called endorphins, and delivering more oxygenated blood to your brain. But yoga may have additional benefits. It can affect mood by raising levels of a brain chemical called gamma-aminobutyric acid (GABA), which is linked to better mood and reduced anxiety.

Meditation also reduces activity in the limbic system, the part of the brain dedicated to emotions. As your emotional reactivity decreases, you have a more moderated response when facing stressful situations.

Medication and talk therapy have traditionally been the preferred remedies for depression and anxiety. But complementary approaches like yoga also help, and yoga compares favorably to other complementary therapies.

A review of 15 studies, published in the journal Aging and Mental Health, examined the effect of a variety of relaxation techniques on depression and anxiety in older adults. In addition to yoga, the 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 seemed to provide the most lasting effect.

Several small studies have found that yoga can help with post-traumatic stress disorder (PTSD). It is not used alone, but as a complementary treatment to help reduce intrusive memories, emotional arousal, and to produce calmer, more stable breathing. Deep, slow breathing is associated with calmer states because it helps activate the parasympathetic nervous system.

Benefits of Yoga for Physical and Mental Health

Researchers still have a long way to go before fully understanding why yoga has such a wide range of physical and mental benefits. Here's what is known so far.

Reduce stress

Daily stress not only wears you down mentally, but it also affects your physical health. It triggers the "fight or flight" response, preparing your body to face an immediate threat. This response increases your heart rate, releases glucose into the bloodstream, boosts inflammation, and redirects resources from non-essential functions such as digestion.

The opposite response, relaxation, calms your body, conserves and restores energy, and keeps functions like digestion in balance. This response is enhanced by yoga. Many benefits of yoga come from stress reduction and its effects on the body.

The vagus nerve regulates important bodily functions such as breathing, heart rate, and digestion. Higher vagal tone means that your body can more easily switch from the stress response to relaxation. High vagal tone is associated with a proper heart rate, good digestion, stable mood, and resilience to stress. Yoga appears to increase vagal tone, which may explain why conditions such as depression and chronic pain respond well to yoga.

Tonifies the Vagus Nerve

Increases Immunity

By combating stress and inflammation, yoga also seems to improve the body's natural defenses, raising antioxidant levels that neutralize free radicals and reduce oxidative stress.

Reduce Inflammation

Stress reduction can also decrease inflammation, which, in the long term, is linked to heart disease, diabetes, and cancer. A 2019 review of 15 yoga studies found that yoga reduced markers of inflammation.

Protects Your Genes

Research suggests that yoga could help your cells age more slowly. This is related to the length of your telomeres, which protect the ends of chromosomes. Reducing stress through yoga may help preserve the telomeres. One study found that meditating daily for 12 minutes increased telomerase activity by 43%.

Regulates Gene Expression

A review of 18 studies found that mind-body practices such as yoga and meditation reduce the expression of genes linked to low-grade chronic inflammation and increase the expression of health-promoting genes. One study showed that a simple meditation practice could activate beneficial genes in both long-term practitioners and beginners.

References

• Harvard Health Publishing (personal subscription, June 23, 2024.)

• Harvard Health Publishing. (2024). Report on Intermediate Yoga. https://www.health.harvard.edu/exercise-and-fitness/intermediate-yoga#excerpt