Polyvagal Theory and a New Evolutionary Response to Stress

Polyvagal Theory and a new Evolutionary Response to Stress

I love the “new science” supporting what the yogis have said for millennia…

The polyvagal theory states that we can train our vagus nerve to not just go from 100% PNS activity to 100% SNS activity ~ but that there are gradients in between being stressed and relaxed.

This is good news as we need a new evolutionary approach to stress. In cave man days which seems to be when our bodies learned the stress response, stress was life threatening… outrun the tiger or you die. Your body is not going to waste a shred of energy on healing that infection or on regeneration because if the tiger eats you it’s for naught. So all systems go to run, fight, and think quick survival.

Most stress is no longer life threatening.  We need a new evolutionary response to stress that allows us the benefit of some circulating stress hormones for motivation and energy without breaking down the entire body in the process.  Turns out we might be able to do this 🙂

This is my understanding of the some of the latest research on the vagus nerve that I have been following done by Dr. Steven Porges in this study on Yoga Therapy and our Vagus nerve

In the polyvagal theory, there are levels of tapping into a little SNS (Sympathetic Nervous System — aka the stress response) activity while we remain predominantly PNS (Parasympathetic Nervous System aka the rest and digest response). This is the new evolutionary response I am talking about.

It’s not new, I learned this is in yoga terms 30 years ago as I began this journey. Yoga postures I learned, put a little stress in our body, but we use our breath and bandhas (remember both bandhas stimulate PNS activity) to mitigate this stress and stay calm and relaxed while we do the “work” in the posture (and part of the work is to relax in the posture!).

Yoga is effectively helping us raise the barre of how much work we can do without tripping our stress response 🙂

This is a big upside to a yoga practice. Learning to control your stress response while you work or do something challenging will allow you the grace under pressure that gives one clearer thinking while they deal with the stressor at hand keeping us healthier and younger while we go through our lives.

Recently a big research paper was released which I came across in a new book “Yoga & Science in Pain care”.

This paper explained polyvagal theory as basically a modern view of yoga’s gunas (sattvic, rajasic, tamasic) or finding balance (sattva) between activity and stillness.

Sattva is the quality of pleasure, calmness and tranquility that serves the function of illumination. Sattva is described as: lightness, clarity, harmony, buoyance, illumination, lucidity, joy and understanding (Stoler-Miller, 2004; Bawra, 2012; Miller, 2012).

Rajas balanced with sattva and tamas creates the motivation and creativity for inspiring change, movement and right action. Conversely too much rajas,  may increase anger, agitation, or anxiety. (Bawra, 2012; Miller, 2012).
Tamas balanced with sattva and rajas may provide form and stability, whereas an over-predominance of tamas may give rise to delusion, inertia or obscuration (
Bawra, 2012; Miller, 2012). “

Polyvagal theory and HRV or heart rate variability can be similar concepts — most people think our heart rate should be a metronome at 70 BPM, but this is not the case. A healthy heart varies from beat to beat depending on what we are doing and thinking. People with a high stress response actually don’t have this variability — they have that driving beat — driving the need to keep moving to protect yourself.

Same goes for our nervous system we need it to be able to have some variability between stressed and relaxed as we go throughout our days. You can support this process in many ways, one is:

Just go throughout your days with your tongue on the roof of your mouth (improving vagal tone), breathing deeply and rhythmically through your nose (stimulating PNS and oxygenating your body), staying connected to your bandhas (more PNS stimulation), and smiling 🙂 And you too can stay young while you work and go through your days.

In this way you too can raise the barre of what you are able to do without any stress hormones!

Heart Rate Variability (HRV)
Understanding HRV

The heart has two main nerves; the accerlans nerve which connects the heart to the Sympathetic Nervous System (SNS) — fight or flight response.  And the vagus nerve which connects the heart to our Parasympathetic Nervous System (PNS) — calming, rest & digest, regenerate response.

The vagus nerve exits our brainstem, and connects to 4 of our 5 our senses — ears, eyes, tongue, skin, (scent connects to our limbic system) and our face, lungs, heart, stomach liver, spleen, pancreas, right kidney, and small and large intestine relaying information along the way between all those systems and organs.   When we have HRV, we can respond to a stressor — then use our vagus nerve to calm us down and not remain in the stress response.  Essentially what we need is our vagus nerve or PNS to be stronger than our accerlans nerve or SNS — we need to literally think of our vagus nerve and our PNS as a muscle and strengthen it so it can override the accerlans and SNS.

For example; you have a disagreement or riff with someone — or are many just experiencing stress, fear, or negative emotions.  You come from work and are greeted by a loving spouse who hugs you and cuddles you and tells you its going to be ok.  The vagus nerve with its sensors relaying information all the way from your gut to your heart to your brain will relay messages of safety, calm, relax -its ok type of messages.  Your vagus nerve will then stimulate the release of a neurotransmitter called acetylcholine which further stimulates your PNS activity which dilates blood vessels so blood can flow, slows heart rate, contracts the smooth muscles that line the tubes in our body and digestive system improving digestion, etc.

Now take the same bad day as above; and picture coming home to a stressed out spouse who is also angry about their day, or neglectful to your relationship, or perhaps under financial stress or work stress too, and is not interesting in connecting with you in any way.  Your nervous system senses this too and your accerlans nerve will keep stimulating the stress response — so your heart rate stays up and your SNS stays in arousal — your heart receives the signal to stay alert so you can run or fight in a moments notice.  No HRV happening there.

Combine this scenario with a disconnect from nature, long work hours, or other family stressors and life becomes a constant stressor.  This leads to chronic decreased HRV.  Decreased HRV is akin to a wounded heart.

There is hope!  No worries if you have a stressful job and a less than supportive spouse or family, you have trees and plants and yoga and meditation and vagal nerve stimulation all day long as I spoke about above.  Here are few other tools to help you have better HRV:

  • Rest – and time away from the stressor.
  • Contemplative movement — or as some call it, sacred movement.  Exercises that help you relax, destress, release tension and tightness such as Qi gong and yoga.  These are systems of exercise that encourage resiliency and improve HRV.
  • Breathing exercises, or what is known as the resonance breath – just slowing down your breath to about a 5 second inhale and a 5 second exhale.  Breathing exercises like nadi shodhana – alternate nostril breathing are especially calming to the mind and nervous system.
  • Get outside — especially to a forest if you can.
  • Aromatherapy – just the act of diffusing oils from trees and flowers can calm your heart and increase HRV — scents of lavender, vetiver, lemon balm, rosemary, and floral scents can instantly increase your calm.  
    • You can put some of the essential oils in sesame oil or olive oil and massage them into your skin for which will even have more of a calming effect because of the touch.  Even the touch of care-ingly massage oils into your own skin will stimulate your vagus nerve and PNS.
    • You can also use a smudge stick and waft around smoke scent from white sage, rosemary, cedar, mugwort — all sustainably harvested of course.  Smudging releases the same volatile oils that are in essential oils and can also improve mood.

Homeostasis vs. Allostasis vs. Allostatic Load – Raising the Barre

Homeostasis — at home in our bodies, even better explained as: at rest at home in our bodies.

Homeostasis is scientifically explained as a very narrow window of operation for key critical systems in our body — it has a limited number of physiologic variability that include pH, body temperature (body temp can only vary by 5-6% without death), glucose levels, and oxygen tension (blood oxygen levels).  

These systems have a very narrow range of operation to be in homeostasis — when we are in homeostasis our body is in the perfect state to heal, digest, regenerate, get rid of mutated cells, fight of pathogens, etc.

Allostasis – Staying at rest, at home in our bodies while we “work”

Allostasis also has a fairly narrow range of physiologic end points that is just outside of what defines homeostasis — it is basically a way of our body finding a type of “homeostasis” that is outside of the narrow range of physiological end points.  So allostasis is the the ability to achieve stability through change.

Primary mediators in the body of allostasis include the HPA axis, catecholamines, and cytokines. the HPA axis is our nervous system relaying information to our hormone system and telling it how much cortisol to release.  A little cortisol is necessary, we need some cortisol just to get out of bed in the morning.  Cortisol has a healthy rhythm; it’s highest when we wake up, and drops throughout the day to its lowest levels at night.  Cortisol becomes unhealthy when stress or extenuating circumstances stimulate cortisol to release and stay high throughout the day or evening.

 Allostasis is basically our body trying to maintain homeostasis while we work and live. Allostasis is homeostasis in action.

We want to encourage allostasis without increasing allostatic load

    • What is the HPA Axis? Bobbi’s HPA definition:
      The HPA (Hypothalamic, pituitary, adrenal) axis, is the hypothalamus sensing information from the nervous system, that sets off a chain of events that stimulate the pituitary gland to stimulate the adrenals to release stress hormones or other hormones for movement — usually this is used to refer to setting off the stress response — but it does not always have to set off a full blown stress response. ________________________________________________________
    • More scientific explanation from Integrative Medicine
      “The HPA axis is responsible for the neuroendocrine adaptation component of the stress response. This response is characterized by hypothalamic release of corticotropin-releasing factor (CRF). CRF is also known as CRH or corticotropin-releasing hormone. When CRF binds to CRF receptors on the anterior pituitary gland, adrenocorticotropic hormone (ACTH) is released. ACTH binds to receptors on the adrenal cortex and stimulates adrenal release of cortisol.

Allostasis is the body adapting to the stressor — integrating the lesson, getting stronger muscles or heart and lung function, etc.  However if allostasis becomes an  allostatic load because allostasis remained high for too long, it breaks the body down.  Allostatic load can be from lack of sleep, too much sugar or food in general, too much exercise, an infection, being exposed to a danger, along with all the other stressors people identify as stress.

For example if you are dehydrated, your body will reduce urine output and sweating to preserve water, this is allostasis.  For a short period this will not harm the body, if the dehydration goes on too long the body will start to overheat easily, and be burdened by toxins the kidneys are unable to get rid of due to lack of water.

Or another example would be exercise and weight lifting — when you lift a weight you break a muscle down, when you rest the muscle rebuilds stronger.  This is allostasis; the body adding more muscle so it can handle the weight load.  When you overtrain — lifting weights breaking muscle down without adequate recovery time in homeostasis to build tissue — your workouts become an allostatic load and start to break down your tissues, or you feel exhausted after your workouts, or you feel very sore at the beginning of your workouts.  These are signs your body is talking to you!  The key to resilience and growth is being able to do your “work” in homeostasis or allostasis without getting an allostatic load.

How do you handle non-life threatening stress?

I came across a study that was interesting; under the stress response males and female will react differently.  The female response to non-life-threatening stress is to “tend and befriend” while the male response tends to be “fight or flight”.  Women will flee from extreme danger, of course, but the differences in how someone responds to a stressor is the difference in how much wear and tear it will have on your body.

Tending and befriending will relax the stress response and bring in more oxytocin –the love hormone, which is needed during times of stress.

On the other hand being defensive or argumentative — fighting so to speak, will increase or sustain the stress response adding to the wear and tear or the allostatic load on your body.

Allostatic load will wear the body down.  In our endeavors we want to tune in to our physiology and make sure we are not pushing ourselves from allostasis into an Allostatic load.

Adding this into “minding your mindstuff” our thoughts can drive us from homeostasis to allostasis to allostatic load.  And it’s all within our control.

Psychoneuroimmunology … a big word that used to be only used alternative circles and is now getting recognition in allopathic circles.  It is:

PNI – Psycho – Neuro – Immunology

Psychoneuroimmunology looks at the response the mind and emotions produce in the body — how these emotions physiologically effect our autonomic nervous system, endocrine system, and immune system.

Basically stress — even stressful thoughts effect the body much the same way as an infection or a virus.  And if you are stressed it paves the way for you to be more likely to get an infection or virus as well, and vice versa — if you have an infection it is a type of stress on the body and makes it easier for you to become more stressed out.  Basically stress is another form of an infection or illness in the body.

You have control over this!  All you have to do is have power of mind; power of mind is developed through minding your mindstuff.  Short meditations (5-20 minutes) is a nice place to start this work.

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