The gastrointestinal tract is home to many immune cells that can be stimulated by certain patterns of intense stimulation, which can help fight infection and reduce inflammation. The gastrointestinal tract is strongly innervated by the vagus nerve (VN), which is the longest cranial nerve and the main nerve of the parasympathetic nervous system. It links the intestinal immune system to the central nervous system and ensures optimal inflammation response. The vagus nerve is also responsible for several vital functions, including heart rate and digestion (Breit et al., 2018).
Vagal nerve stimulation (VNS) is an effective treatment for various conditions, including but not limited to epilepsy, depression, and anxiety (Breit et al., 2018). Yoga results in cardio-respiratory stimulation of the VN, which in turn, leads to improved physical, cognitive, and emotional health (Howland, 2014, Zope SA & Zope RA, 2013). Below we will discuss the main therapeutic effects of VNS and its underlying mechanisms.
Therapeutic benefits of the VNS
Therapeutic benefits of the VNS
Vagus nerve stimulation is an effective and widely used treatment for epilepsy. Studies examining the effects of VNS devices have shown a reduction in seizure frequency of about 50% in half of the patients after only two years of treatment (González et al., 2019). Yoga, in turn, not only stimulates the vagus nerve but also reduces stress, which is an independent risk factor for seizures in people with epilepsy (Panebianco et al., 2017).
Depression
Yoga practice, especially yogic breathing, directly stimulates the vagus nerve and increases vagal tone, resulting in improved heart rate, mood, cognition, stress perception, and autonomic regulation. Research shows that yoga practices are an effective way to treat mild to severe depression. Moreover, eight weeks of Simplified Kundalini Yoga (SKY) has been found to significantly improve symptoms of anxiety and depression in antidepressant-resistant patients (Breit et al., 2018).
Breathing exercises and Iyengar yoga asanas have also been found to increase vagal tone and improve symptoms of depression (Breit et al., 2018).
PTSD
Mindfulness-based practices that reduce stress were proved to improve PTSD symptoms by increasing the vagal tone and downregulating the stress response. Yoga practices were even effective in decreasing PTSD symptoms after extremely stressful events such as natural disasters (Breit et al., 2018).
Immune System
The abdomen is full of lymph nodes that fight ingested food antigens, harmful bacteria, and opportunistic microbiota that lead to inflammation and gastrointestinal infections (Miller, J. 2014). Vagus nerve fibres are essential to the neuroendocrine-immune axis as they link the abdominal lymph nodes to the central nervous system. The neuroendocrine-immune axis, in turn, coordinates the body’s neuroendocrine responses to inflammation (Breit et al., 2018).
Yogic breathing, body inverting asanas and self-massage with a squishy ball stimulate the vagus, therefore helping to improve abdominal immunity (Miller, J. 2014). Yoga props such as yoga blankets, yoga bolsters and yoga blocks can be used to massage the abdomen.
Cancer
In recent years, more research has focused on vagus nerve stimulation as a potential treatment for cancer. A study in rats infected with lung cancer found that vagus nerve stimulation with deep abdominal massage stimulated the immune system and reduced the size of tumours (Miller, J. 2014). Scientists believe that moving the belly down on the ball, combined with deep yogic breathing, has a similar effect on cancer patients. It has been found that stimulation of the vagus nerve promotes the activation of natural killer cells, specific lymphocytes that fight tumour cells.
Also, studies have shown that increased vagus nerve activity has been associated with longer survival among people with colon, breast, prostate, and lung cancers. In addition, animal studies show that increased vagal tone has been associated with a lower chance of developing certain cancers (Reijmen et al., 2018).
Vagotomy (removal of a part of the vagus nerve via surgery) is a treatment option for peptic ulcers. However, this procedure is associated with an increased risk of several types of cancer, including lung, stomach, colon, and biliary tract cancer. The latter fact also points to the role of the vagus nerve in cancer prevention and prognosis (Reijmen et al., 2018).
Ways to Stimulate the Vagus Nerve
Yogic practices that stimulate the vagus nerve are:
- Yoga and Meditation via abdominal breathing (Bhastrika and Breath of Fire).Respiratory processes modulate the vagus nerve (inhalation suppresses its activity, while exhalation enhances it) (Chang et al., 2015). Therefore, breathing exercises can be used to regulate vagal tone and improve mental and physical health (Gerritsen & Band, 2018).
- Gargle or Yodel to this Sound of Music Song (The Lonely Goatherd)
- AND Sing loudly!
Ways to incorporate abdominal self-massage in your yoga routine:
- Oki-do self massage hara technique
- Bellows breath with intense abdominal contractions and mobilisations
- Using yoga props in postures that put pressure on the abdomen
Ways to move lymph around the body in yoga:
- Inversions
- Abdominal massage
- Intense abdominal contractions – use your bandhas with exhalation and breath holds
May your lymph flow freely in your gut and your vagal tone be good.
Celia Roberts
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