The human nervous system is a complex structure involving the brain, the spinal cord, the sensory organs and many nerve receptors throughout the body. It is responsible for cognition, the operation of our internal organs and your ability to be aware of the world around you. Yoga can improve the functioning of the nervous system by changing the way you react to stress.
Structure of the Nervous System
The nervous system contains two main branches: autonomic and somatic. The autonomic system controls involuntary, or unconscious, bodily functions, such as the beating of the heart muscle and the actions of smooth muscles such as those found on the lungs and other organs. The somatic nervous system controls voluntary muscle action such as walking. The autonomic system is the branch that can be influenced by yoga practice.
Autonomic Nervous System
The autonomic nervous system is also divided into two branches: the sympathetic and parasympathetic nervous systems. These two branches work in opposition to each other. The SNS is in charge of short-term reactions, such as what happens when you are frightened or otherwise stressed: It shuts down nonessential body functions such as digestion and increases others, such as heart rate, in order to get more blood to the skeletal muscles to handle the body's fight-or-flight response during times of stress. The PNS comes into play after the stress had diminished; it calms and relaxes the body to bring it back to a balanced state, or homeostasis.
Effects of Yoga
Yoga practice seems to encourage the action of the PNS so that the body recovers faster from stress and its related emotions, such as anxiety. A 2010 study published in the "Journal of Alternative and Complementary Medicine" by a team of researchers from Boston University found that yoga practice reduced anxiety to a greater extent than just walking. The study also measured the presence of GABA, a neurotransmitter that stimulates the PNS, and found that this substance increased in the yoga practitioners. GABA is less abundant in chronically depressed or anxious people. A 2012 paper by the same Boston University researcher theorized that the beneficial effects of yoga could be applied to nervous system disorders such as depression and post-traumatic stress.
Deep breathing, an important component of yoga practice, activates the PNS, said yoga therapist Sandra Uyterhoeven, in a 2006 article for "Yoga Therapy in Practice." Regular practice of yoga, especially breathing and meditation, tends to reinforce the relaxation response. Uyterhoeven states that by focusing attention on positive qualities, those qualities grow more influential. This means that a heightened response of anxiety or stress can change into a more relaxed state just by focusing on the experience of calmness.
- Ohio State Wexner Medical Center: About the Nervous System
- Yoga Journal: The Scientific Basis of Yoga Therapy
- Journal of Alternative and Complementary Medicine: Effects of Yoga Versus Walking on Mood, Anxiety and Brain GABA Levels
- Medical Hypotheses: Effects of Yoga on the Autonomic Nervous System, GABA, and Allostasis on Epilepsy, Depression, and Post-Traumatic Stress Disorder
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