Behind the Scenes
Pelvic Health and the Autonomic Nervous System
One of the questions I ask patients during their first physical therapy visit is “Did you experience any life changes or stressful events around the time that your symptoms started?” And why might that be important?
Our bodies are constantly registering input via the nervous system - from our environment, from the people we interact with, and even from our own bodies. There is a constant conversation going on between the cues perceived by the nervous system and reactions to those cues (i.e. changes in bodily functions like heart rate, digestion, alertness, and breathing). And it’s not only negative stress that causes our bodies to react. It could be something grand like an anticipated move, a new relationship or job change. All of these nervous system responses are happening behind the scenes so we might not even be conscious of the correlation.
The Nervous System: A Primer
We can conceptualize, categorize, and contain the nervous system in many different ways. For today’s purposes we are considering the voluntary vs autonomic nervous systems with a focus on the autonomic system.
The voluntary nervous system is what we “have control over”. For instance. I want to pick up that cup, my brain tells my body what to do in order to make that happen.
The autonomic nervous system (ANS) refers to the things happening behind the scenes in our cardiovascular, respiratory, gastrointestinal, urinary, and reproductive systems.
The autonomic nervous system is broken up further into the parasympathetic, sympathetic, and enteric (to be covered more in a future post) systems. And then, of course, the parasympathetic system is further divided into dorsal vagal and ventral vagal under polyvagal theory. Let’s dig a little deeper.
Sympathetic Nervous System:
The sympathetic system is responsible for action or mobility. It’s the “fight or flight” system. It is often stimulated when something scary or exciting happens or in anticipation of something scary or exciting happening.
Increased sympathetic activity…
Quickens the heart rate and increases blood pressure
Makes breathing faster and shallower
Sends more blood to skeletal muscles
Produces sweat and gooseflesh
Makes hairs stand on end
Dilates pupils
Decreases GI tract motility
Releases epinephrine and norepinephrine into the blood stream
Inhibits urine production
Inhibits arousal
The nerves that send sympathetic signals from the brain and spinal cord (central nervous system) to the organs and skin are located in the thoracic and upper lumbar spine - where the rib cage attaches to your spine and couple vertebrae below the rib cage.
Parasympathetic Nervous System:
The parasympathetic system is commonly known as the “feed and breed, then rest and digest” system. It prioritizes our basic staying alive functions like digestion, energy storage, defecation/urination, and reproduction.
Increased parasympathetic activity
Slows heart rate and lowers blood pressure
Deepens and slows breath
Increases digestive enzyme production
Increases gut motility (movement of food through the intestines)
Increases urine production and bladder contraction
Increases blood flow to genitals
The nerves responsible for transmitting parasympathetic signals are located in the brainstem, cervical spine (neck) and sacral spine (back of the pelvis). One nerve in the brainstem called the vagus nerve (wanderer) travels down through the neck and chest and controls a lot of parasympathetic activity. This nerve has two branches, dorsal vagus and ventral vagus. In the mid 90s, Stephen Porges proposed the polyvagal theory to explain how these two branches impact the body differently.
Polyvagal theory: The Back Story
Polyvagal theory proposes that vagus nerve’s two branches have different impacts on their target organs. It was developed after Porges observed two heart rate phenomena in newborns, one protective and the other dangerous, both controlled by the vagus nerve. One was a larger amplitude in the difference between heart rate during an inhale and heart rate during an exhale (known as respiratory sinus arrhythmia) and the other was a significant decrease in resting heart rate (bradycardia). This became known as the “vagal paradox” and prompted Porges to investigate further and eventually develop the polyvagal theory to explain these observations.
Dorsal Vagus
The dorsal branch of the vagus nerve is associated with immobility or shutdown in the face of danger or stress. Think fainting, dissociating, feeling extreme overwhelm or paralyzation. It is the oldest autonomic pathway, evolutionarily speaking, and is present in most vertebrates.
Ventral Vagus
The ventral branch of the vagus nerve is associated with the feeling of safety and connection. It slows the heart rate and inhibits the sympathetic nervous system’s fight or flight response and the release of cortisol. Polyvagal theory also proposes that the due to the proximity and connection between their cell bodies, the vagus nerve integrates with the nerves that control facial expressions, eye gaze and vocalization which promotes social engagement. It is the newest autonomic pathway and only present in mammals.
Three Principles of Polyvagal Theory
Hierarchy: The nervous system responds to cues in order of the “age” of the system. Safe cues promote social engagement (ventral vagus activity) and dangerous cues move through fight or flight (sympathetic activity) and then to freeze (dorsal vagus activity)
Neuroception: Our nervous system is CONSTANTLY taking in cues or information from our environment, inside our body, and those we interact with and assessing them for safety/danger.
Co-regulation: Our nervous systems are responding to our social interactions moment to moment, assessing for safety and creating bonds with people we feel safe with.
So to recap…or TLDR
We have three autonomic nervous system states. Here they are in order of youngest to oldest, evolutionarily speaking.
Social engagement or our calm, safe, connected state regulated by the ventral vagus and other parasympathetic nerve activity. In this state the body prioritizes digestion, energy storage, and reproduction. The nervous system filters out irrelevant stimuli and sensations.
Fight or flight regulated by the sympathetic nerves. In this state the body is ready for action. There is a heightened awareness of stimuli and sensations.
Freeze regulated by the dorsal vagus nerve and other parasympathetic nerve activity. In this state the body immobilizes to conserve energy and protect itself against threat. It may present as a feeling of dissociation or overwhelm.
The Autonomic Nervous System and the Pelvic Floor
I truly believe that you cannot talk about pelvic health without talking about the nervous system. The pelvic floor is integral to three basic human functions (peeing, pooping, and sex) that are largely controlled by the autonomic nervous system.
There are two urinary sphincters and two anal sphincters; one is voluntarily controlled by you and the other is controlled by the autonomic nervous system
The coordination between bladder and rectum contraction and pelvic floor relaxation critical for health bladder and bowel function is regulated by the autonomic nervous system
Signs of sexual arousal like lubrication, blood flow to the genitals, and erections are regulated by the autonomic nervous system
And, of course, the big climax - that’s all ANS too.
Because there is so much autonomic innervation in the pelvic floor, it is common for people to '“hold tension” in these muscles. Think of jaw tightening, or shoulder scrunching - the things that you may catch yourself doing when you realize that you are stressed. Often times the pelvic floor muscles are clenched also, we are just not as “tuned in” to this part of our body and so we may not realize it. Next time you are stressed, check in with your anus and see if it’s clenched or relaxed…
This muscle tension is a sympathetic nervous system response. The body is getting ready for action. The pelvic floor is part of the core and, therefore, crucial for stabilizing and moving the body. When we are in an extended state of sympathetic activity, these muscles aren’t getting the message that they can relax.
In a sympathetic state, breathing shallows which means we stop using the diaphragm and start using our neck and shoulder muscles. The movement of the diaphragm is related to the movement of the pelvic floor and when the diaphragm gets stiff, the pelvic floor does too.
When we are in a sympathetic state our attention to sensations is heightened which can make the experience of chronic pain louder. I sometimes hear people say that they were doing something fun over the weekend and their pain didn't go away but they just didn’t notice it. That is pain going away! Pain is an experience, if one is not experiencing it, it is not present. And the reason they didn't notice it is because it wasn’t as loud when they were in a safe and connected state.
Why is this important?
I know it’s said over and over but it bears repeating. It really is all connected. We can address the individual body parts, muscles, nerves, etc. but if we ignore the state of the nervous system we are missing a big part of the picture. Of course, managing stress and “regulating” the nervous system is easier said than done. There are many strategies and, like most things, there is no one size fits all solution. Everyone’s nervous system is so different. Your nervous system has been shaped by every experience you have ever had and therefore responds in a truly unique way.
I like to start here:
Notice when you feel calm, safe and connected: What are you doing? Who are you around? What is the environment like - sounds, images, lighting, indoors or outside?
Notice when you feel anxious, nervous or overwhelmed: What are you doing? Who are you around? What is the environment like - sounds, images, lighting, indoors or outside?
Discovering your nervous system’s likes and dislikes is a great way to get to know what makes you feel safe. What are your unique responses? Start by increasing the good inputs and decreasing the challenging ones. It does’t have to be big things. Maybe consider what music you listen to on your way to work. Maybe commit to spending a little time outside every day. Maybe adjust the lights in your office. Remember, your nervous system is taking in EVERYTHING. Even small changes to the inputs make a difference.