The nervous system is full of complexity and intricacy. The practice of yoga can directly affect parts of the larger nervous system, the Parasympathetic Nervous System (PNS) and the Sympathetic Nervous System (SNS), its counterpart.
The PNS is the “rest or digest” part of the larger Autonomic Nervous System (ANS), while the SNS is the “fight or flight” counterpart.
It is no secret the practice of yoga has been scientifically proven to activate the PNS, the “rest and digest” part of the Autonomic Nervous System. However, there has not been much written about the effects of yoga on the counterpart of the PNS, the Sympathetic Nervous System (SNS).
Understanding the Parasympathetic vs. Sympathetic Nervous System
While some types of yoga are intended to slow the body down, there are other practices that do the opposite, affecting the Sympathetic Nervous System (SNS), the counterpart of the Parasympathetic Nervous System (PNS). These types of yoga practices speed up the body.
The PNS is the “rest or digest” part of the larger Autonomic Nervous System (ANS), while the SNS is the “fight or flight” counterpart. The SNS is activated when we feel a sense of danger, or a perceived threat.
When practicing certain types of yoga, a relaxation response is activated (PNS response) by the body slowing down.
Slower, or quieter yoga practices, such as this one, includes calming or gentle asanas (poses), deep breathing and meditation. Some yoga practices can help alleviate stress by slowing down various functions of the body, resulting in an overall sense of calm.
Conversely, there are yoga practices that activate the SNS that are quite different. However, although different, these can result in psychological, emotional and physiological benefits.
Here’s The Science Behind the Sympathetic Nervous System
The SNS in the Autonomic Nervous System is responsible for maintaining a balanced state (homeostasis) within various organ systems within the body.
The sympathetic responses are about action, like the ones which get activated just before one wakes up from sleep, or a relaxed state of the body which is antagonistic to the sympathetic response.
Here’s how it works when activated:
The SNS works in conjunction with cortisol and adrenaline leading to an increased heart rate, changes in blood sugar levels, and increased blood pressure. Blood and oxygen are sent to the larger muscles of the body, like the trunk, and arms and legs, so that one can escape perceived danger or threats of harm.
The SNS is activated when we feel a sense of danger, or a perceived threat.
There are chemical impulses which travel from the spinal cord to the target tissue, and stimulate processes like increasing the heart rate, shutting off the digestive system, dilating the bronchial tubes for accommodating more oxygen rich air, dilating the pupils, constricting the blood vessels for spiking the blood pressure, and activating perspiration.
There are afferent messages, or signals, which travel from the receptors of the external threats to the spinal cord for eliciting the afferent response from it.
Now – Here’s How This Information Applies to Yoga
In certain types of yoga such as Yin Yoga, Hatha Yoga or Restorative Yoga, the PNS is stimulated. The heart begins to slow, breathing becomes regulated, or deepened by , resulting in a calming or peaceful effect. Practices that typically activate the PNS are gentler, quieter practices and are slower in nature.
In more dynamic practices, such as Kundalini Yoga, there may be more challenging postures. The pace of the class or the flow may increase.
Or for example, when practicing Warrior III Pose, it requires balance, concentration, and is fueled from the stimulation of the SNS, allowing the flow of energy, neurotransmitters, and hormones to energize the body to hold the posture.
When we flow through postures, or jump back to Chaturanga Pose, the heart rate increases, the blood is pumping, and the body is energized.
Our immunity becomes strengthened, we become stronger, build strength, and increase endurance.
When we practice Breath of Fire, it is an intentional, powerful breath that can energize and revitalize you as well as tests your endurance.
The sympathetic responses elicited during more dynamic yoga and movement practices are healthy ones. Our immunity becomes strengthened, we become stronger, build strength, and increase endurance.
Dynamic yoga and movement can strengthen your response to perceived stressors in a controlled environment.
Similar responses are felt during other more vigorous exercises, such as power walking, swimming, running, or biking. Dynamic yoga and movement can strengthen your response to perceived stressors in a controlled environment.
Therefore, when actual danger happens in the outside world, these practices, when done regularly, not only strengthen you physiologically, but mentally and emotionally. You feel stronger as a whole, thereby tending to your mind and body, all by regulating your stress response through yoga.
Tips from a Psychotherapist and Yoga Teacher
The practice of yoga is beneficial in so many ways, whether it be a more gentle practice or a demanding one. It just depends on what your intentions for your practice are, the type of yoga you choose, as well as the instructor’s teaching style.
In my own practice, I have found that listening to your body and tending to your individual needs is always best when choosing a yoga practice.
To learn more about the different types of yoga and how they differ, I recommend this reading Instructing Hatha Yoga: A Guide for Teachers and Students by Diane M. Ambrosini to both teachers and students, as it breaks down the different types by postures, lengths, breaths taken and more.
Practicing Yoga for the Sympathetic Nervous System: The Takeaway
Some days, you may want the challenge of an Ashtanga Yoga class, and others, you may want the ease of a Restorative Yoga one. Listen to your body and honor what it needs, honoring both aspects, SNS and PNS, of the Autonomic Nervous System.
Love the Thought of Combining the Two? Try VinYin Yoga!
You also can read more about the different types of yoga here.
It’s important to educate yourself on the different types of yoga practices to see what works best for you. Make sure you take modifications as needed and ask your instructor what you can expect from the class to decide if it is suitable to your individual wants or needs.
Whichever style you choose, the immense benefits of yoga remain the same.