The Autistic and ADHD Nervous System
The Autistic and ADHD nervous system is a vulnerable and sensitive thing. Sometimes, as neurodivergent people, we struggle to adapt to change, stress, and conflict. More often than neurotypicals, we experience panic attacks, anxiety and depression disorders, difficulty regulating our emotions, and more. The answers as to why that is and what we can do to change that rigidity are in understanding the nervous system.
When I’m working with my neurodivergent clients, part of what I do is help them understand what’s going on in their nervous system. As an Autistic person and ADHDer myself, I know first-hand how important this understanding is. When we learn about our nervous systems, we can begin taking our power back. We learn the reasons why our nervous systems behave the way they do so that we can learn how to influence them for our health and overall benefit.
In this article, you will learn about your nervous system and learn about ways you can begin to create more balance. If you are looking for more specific help learning about nervous system exercises and want help implementing them, I recommend checking out my Nervous System Workbook, Here, you’ll learn about your own nervous system, track symptoms, and get workbook pages to help you begin introducing exercises into your routines.
How to Use the Article
There’s a lot of information here packed into one article. So please take your time and come back if you need to. At the end of this article, there are some suggestions and exercises to try out. As with those, it’s best to try them one or two at a time. Too many changes to a routine at once can be overwhelming to the body and do more harm than good. So I recommend going slow while you’re experimenting with the exercises and adding them into your routine.
Before diving into the neurodivergent nervous system, let’s do a refresher on what we even mean when we’re talking about “the nervous system.”
Autistic & ADHD Nervous System Anatomy & Physiology
In the human nervous system, there are two major parts. First is the central nervous system (CNS), which is made up of the brain and the spinal cord. Simply, the central nervous system is responsible for receiving sensory signals, processing information, and sending motor signals to the body. This is like the control center for the nervous system. No sensation exists until the signal hits the brain.
The second is the peripheral nervous system (PNS), which comprises all nerves, neurons, and ganglia outside of the brain and spinal cord in the rest of the body. This system is responsible for sending commands from the CNS to the body via motor neurons and receiving information about the internal and external environment via sensory neurons. The PNS plays a vital role in the mind-body connection.
The Peripheral Nervous System
Let’s zero in on the peripheral nervous system for a moment. The PNS can also be divided into two major parts. The first is the somatic nervous system. The somatic nervous system is voluntary and is responsible for all voluntary movement. So when you open and close your hand or kick a soccer ball, those movements are controlled by the somatic nervous system.
The second part of the PNS is the autonomic nervous system. This system is responsible for all movements of the body that are not in our conscious control. For example, our digestion, heart rate, blood pressure, metabolism, breathing rate (most of the time), and more are all under the control of this system. These things happen on an autonomic level, much like a sneeze.
When we’re talking about trauma, anxiety, nervous system regulation, etc., the autonomic nervous system is the most important player. Therefore, for the rest of the article, we are going to focus on this nervous system: learning about it and learning how to influence it.
The Autonomic Nervous System
Like the other broader categories of the human nervous system, the autonomic nervous system can also be divided into two parts. First is the sympathetic nervous system, and second is the parasympathetic nervous system. In a regulated body (aka one that is balanced), both of these systems work together similarly to the gas and the break petal in a car. The sympathetic nervous system is like the gas pedal, activating and accelerating the body’s systems. For example, when your heart rate increases, that is the result of sympathetic nervous system activation. The parasympathetic nervous system is like the break, working to slow the body’s systems down. For example, when your heart rate slows, this is the parasympathetic nervous system at work.
The hypothalamus, a part of the brain, is what is in control of these two systems. This part of the brain is what is responsible for the body’s state of homeostasis and therefore acts like the driver of the car. In a regulated body, the hypothalamus can smoothly use both systems to keep us in a state of nervous system balance.
Let’s get into what this looks like in more detail.
The Sympathetic Nervous System
The sympathetic nervous system is responsible for activating the body. When we are stressed, we can really see this system in action. The sympathetic nervous system kicks on our “fight or flight” response when we are stressed. Several things happen when our fight-or-flight is advocated: our heart rate, breathing rate, and blood pressure increase. Pupils dilate, our muscles tense, and more. All of this is to protect the body from threats by mobilizing us for action. These physical changes are accompanied by hormonal ones. During a stress response, we get a rush of adrenaline and cortisol which boost our energy and further help the body prepare to deal with the stressors.
Here is a list of changes that happen to the body when our sympathetic nervous system, or “fight or flight” response, is activated:
Rapid and varied heart rate
Fast, shallow breathing
Increased blood pressure
Dilated pupils
High levels of adrenaline and cortisol
Muscle tension
Increased energy
Increased vigilance
Narrow focus
Slow digestion
Poor immune system function
Decreased sexual arousal
All of these changes happen to help us better fight the stressors or run away from them, take in critical information about our environment, and slow down bodily processes that aren’t necessary to keep us safe at the moment (such as digestion).
But remember, all of this is unconscious. That means that whatever the body sees as a threat, its threat response will activate—regardless of how reasonable you think it is! So whether you are stocked by an animal in the woods or your boss tells you they need to talk to you privately, the stress response will be the same. For neurodivergent people, because our bodies are more sensitive to stimulation than the average neurotypical person, a loud sound or an unexpected touch can trigger this stress response, too.
The Parasympathetic Nervous System
Working in the opposite direction, the parasympathetic nervous system is what allows our bodies to slow down. This system is what is responsible for our state of “rest and digest.” You may be able to see this system in action at the end of the day, while you’re stretching, or while you’re meditating. When you take the time to rest, your heart and breathing rate decrease, you take fuller breaths, your muscles relax, and so on. Like how sympathetic activation is critical to keep us safe and alive, parasympathetic activation is critical for us to properly recover. Parasympathetic activation allows our digestive systems to properly digest our food, our bodies to heal and fight off infections, and our minds to go to sleep.
When we’re in this state of “rest and digest"” this is what’s going on inside our bodies:
Slow and stable heart rate
Deep breathing
Decreased blood pressure
Relaxed pupils
Low levels of adrenaline and cortisol
Relaxed muscles
Decreased energy or sleepiness
Decreased vigilance
Broad awareness
Increased digestion
Increased immune system function and bodily repair
Increased sexual arousal
Like the sympathetic nervous system, this system is completely unconscious. That means that our bodies turn on our “rest and digest” responses only after assessing our environment and deeming it safe—regardless of how relaxed you think you should be. For neurotypicals, resting is relatively easy because their bodies aren’t picking up as much information as ours usually do. But it can be difficult for those with neurodivergence or trauma to convince our bodies they’re safe.
Before jumping into what it looks like for these two systems to be out of balance and what that means for neurodivergent people, let’s first go into more detail about what’s at play when assessing how regulated our nervous systems are. When getting to know our autonomic nervous system, there are two things we focus on: the vagus nerve and vagal tone.
The Vagus Nerve
The 10th cranial nerve, also known as the vagus nerve, is the largest cranial nerve belonging to the parasympathetic nervous system (that’s very important to know!). The word “vagus”’ in Latin means “wanderer,” giving the the nerve it’s second nickname, the wandering nerve. The nerve has been given this name because of how it meanders through much of the internal organs, making it the most important nerve in the gut-brain axis. The vagus nerve is responsible for regulating digestion, heart rate, breathing rate, sexual arousal, reproduction, and even reflexes like sneezing, coughing, and swallowing. It is what connects the brain to most of the internal organs.
In Dr. Porges’ Polyvagal Theory, we know that the vagus nerve has two sides: the ventral vagal system and the dorsal vagal system. What are these two sides responsible for?
The Ventral Vagal System
When we are feeling grounded, regulated, and flexible, that means the ventral vagal system is running the show. The ventral vagal system is the front side of the vagus nerve. When it’s activated, it helps these two systems (sympathetic and parasympathetic) work together in harmony so that we can stay in a place of equilibrium. Just the right amount of energy and mobilization paired with the about of rest. We’re able to rest, breathe, digest our food, be socially engaged with others, feel creative and energized, process our emotions, and experience resilience to stress. When we go to sleep, it is our ventral vagus nerve allowing us to do that. And this part of the vagus nerve is critical for digestion, learning, the immune system, and all kinds of repair.
The Dorsal Vagal System
During times of extreme stress, our dorsal vagus nerves often take over. This part of the vagus nerve is responsible for protecting us from having to experience pain and trauma by shutting our systems down, causing numbness and dissociation.
Remember: the vagus nerve is a part of the parasympathetic nervous system, so when it reacts to stress, it works by stepping on the brake pedal. Let’s say you are hiking up a mountain, and you fall off a cliff. The dorsal side of your vagus nerve will quickly activate to shut you down and numb you out. If the cliff isn’t very tall, the dorsal vagal system may just make you black out for a moment until your body knows it’s safe again. But if the cliff is really tall, your dorsal vagal system will likely make you pass out. In both cases, it’s working to prevent you from experiencing the pain, fear, and trauma of the experience. It’s protecting you!
Vagal Tone
“Vagal tone” is a term we use when discussing the vagus nerve activity. High vagal tone equals high vagal activity. When we have high vagal tone, that means our ventral vagal system is in control, which, as stated above, allows us to feel more regulated and to recover from stressful events quickly. When we have low vagal tone our vagus nerve struggles to flexibility adapt between these two systems. This results in more strain and stress on the nervous system. Several studies have found that Autistic and ADHD children and adults have low vagal tone, meaning our nervous systems struggle to adapt to changes. This is what I call the “rigid nervous system” because the system does not as flexibly adapt.
When talking about nervous system healing and increasing our capacity for stress and change, vagal tone is a huge part of the conversation. The higher one’s vagal tone, the larger their window of tolerance (which I’ll discuss in a moment). Increasing the window of tolerance means increasing vagal tone.
So what does it mean for the autonomic nervous system to be out of balance, and what can we do about it? Let’s get into it.
Autistic & ADHD Nervous System and The Window of Tolerance
When our nervous systems are in balance, we are in what’s called the window of tolerance. Here, our minds and bodies can easily and efficiently respond to stress, we are present and calm, and we quickly recover from stress. However, the window of tolerance has its limits. When we experience extreme stress that we’re unable to recover from or when we are continuously exposed to stressors without the support or time we need to work through them smoothly, we exit the window of tolerance and enter either hyperarousal or hypoarousal.
Hyperarousal
When we exit our window of tolerance, we may go into a state of hyperarousal. During the state of hyperarousal, our bodies are mobilized for action and preparing to face danger (think sympathetic mode). In a state of hyperarousal, our sympathetic nervous system gets turned way up, and our parasympathetic nervous system gets turned way down. Therefore, in this state, we experience exaggerated symptoms of sympathetic activation. We don’t just feel energized and vigilant; we can feel very angry, out of control, anxious, hypervigilant, and even paranoid.
If we’re dealing with an immediate threat that lasts only a few minutes, these traits are very useful for protecting us and getting us out of a dangerous situation. Evolutionarily, hyperarousal was a smart and critical adaption to the environment. To properly recover from the hyperaroused state, it was important to be able to “shake it off” after the stress was gone. Meaning it was important to be able to safely get the excess energy out once getting out of danger.
However, Western society has created many subtle stressors we have to encounter on a daily basis and has prevented us from being able to “shake it out.” This means that many of us are stuck in the stress cycle and have not completed the stress cycle. Because our bodies don’t know the difference between public speaking, getting into a fight, paying bills, and getting chased by a bear, our bodies react the same way, and many of us live in a state of hyperarousal.
Hypoarousal
Alternatively, we may respond to acute stress by going into the hypoarousal state. This is a state of immobilization and shutdown.
If hyperarousal is the sympathetic state, then hypoarousal is the parasympathetic state. When hypoaroused, our minds and bodies shut down to protect us from overwhelm—pain and sensory signals decrease (this is the body trying to protect the body from incoming pain, you will notice animals often go into this state right before they are about to be eaten by a predator-it’s the body’s way of preparing them for death and protecting from the pain).
Our parasympathetic nervous system is turned way up, and our dorsal vagal system takes over. Therefore, we experience exaggerated symptoms of the parasympathetic state, including fatigue, dissociation, numbness, foggy minds, immobilization, depression, and sometimes even blackouts and dissoication. It’s like being a deer in the headlights or a possum playing dead.
Like I said under dorsal activation, this mode is designed to keep us from experiencing too much stress and trauma. If we can’t avoid the trauma or fight it off, our bodies respond by entering the freeze response. Another evolutionary advantage of hypoarousal is it helps us to “play dead.” If we get caught by a bear and pass out, then the bear, thinking that we’re dead, may change its mind and leave us alone. And then we survive! So in evolutionary terms, hypoarousal makes a lot of sense.
However, as I said, modernity has replaced bears with deadlines and Karens. Dealing with stressors that are acute and long-lasting isn’t really something our bodies have evolved to do. If our bodies can’t consistently find sources of safety, then we can get stuck in this state of immobilization. This can feel express itself through chronic fatigue, headaches, low-grade dissociation, and sickness.
Faux Regulation
Before leaving the conversation of hypoarousal it’s important to note faux regulation. Faux regulation is when a person looks regulated on the outside to others, but is internally stressed and dysregulated. When we are in a state of faux regulation, our nervous systems are shut down and in a hypoaroused state. So to others, we appear calm and collected, but on the inside, we are frozen and numb. Autistic people are especially prone to this. This is why, when we have may have a sensory shutdown but appear calm to everyone else. This is particularly true among high-masking Autistic people who have learned to survive by shutting our bodies down.
Understanding Your Window of Tolerance
When we are in our window of tolerance, we feel mindful, curious, open, engaged, and present. We effectively manage our emotions and stress. The larger our window of tolerance, the more we can handle while staying in this present state. A large window of tolerance equals a healthy, regulated nervous system.
However, if our window of tolerance is small, we quickly get triggered in a dysregulated state—we quickly become hyperaroused (angry, anxious, irritable, etc.) or hypoaroused (frozen, dissociated, numb, etc.). There are plenty of reasons why someone’s window of tolerance may be small, including PTSD, neurodivergence, anxiety disorders, and more. Neurodivergent nervous system tend to be more rigid than neurotypical ones, therefore, our window of tolerance tends to be smaller.
Expanding the Window of Tolerance in Autistic & ADHD Nervous Systems
If you want to begin to expand your window of tolerance, then it’s important to begin with understanding it. By regularly checking in with your body and using the provided infographics, you can notice where your nervous system is at any given time. And by consistently checking in in this way over time, we begin to see nervous system patterns and can track and observe when we are in our window of tolerance. Once we have that information, we can introduce exercises to expand this window.
Heart Rate Variability
One key factor in measuring vagal tone and the window of tolerance is tracking heart-rate variability (HRV). HRV measures how much variation there is in your heart rate over time and in changing situations. Someone with a high vagal tone—or a large window of tolerance—has more variation in heart rate and increased HRV. Likewise, someone with a low vagal tone has low HRV.
If you’d like to track your HRV, using an Apple Watch or a FitBit is the best way. By writing down your HRV each week, both before and after beginning to introduce vagal tone exercises, you get to witness your nervous system building more capacity.
Increasing Vagal Tone
This section is full of lifestyle changes and habits you can make to increase your vagal tone. By increasing your vagal tone, you increase your tolerance for stress and increase adaptability, relaxation, curiosity, and a sense of safety. Living in a nervous system that is easily triggered, vigilant, or shut down creates more fear, discomfort, and lack of fulfillment. Everyone deserves to live in a regulated nervous system! So here are some ways you can begin working toward that internal stability.
Remember: please take it slow. These practices cannot be made all at once. By making too many changes at one time, you can overwhelm the nervous system and cause it to resist the exercises. The goal here is to create safety, which means moving slowly and mindfully. We can’t heal with the same hustle that caused the trauma! I recommend starting with one exercise (whatever calls to you first) and working with that for a few weeks to a month before moving on. When we’re dealing with rigid or traumatized nervous systems, they require that we show them a lot of proof that we’re safe before they begin to relax.
Besides working through these exercises, I also recommend seeing a somatic practitioner. They’ll be able to help you better integrate these practices into what your body specifically needs.
Breathwork
You’ve probably heard it a million times, but breath work is one of the best practices for regulation. Slow, deep breathing activates the vagus nerve and, therefore, the parasympathetic nervous system. It helps to ease anxiety, re-focus the mind, and ground the body. Likewise, fast-shallow breathing activates the sympathetic nervous system and creates activation when the body is stuck in an immobilized state.
Cold Exposure
Studies have shown that cold exposure increases vagal activity and HRV as well as decreasing sympathetic responses. Cold exposure can look like adding 30 seconds of cold water to the end of a shower, dipping your face in a bowl of ice water, or putting ice on the back of your neck for 30 seconds to a minute. Cold exposure to the neck has been shown to be particularly effective.
Exercise and Movement
Exercise has been shown to increase HRV by stimulating and toning the vagus nerve. Vigorous movement (like taking long walks or going for runs), weightlifting, and somatic movement are all great options for increasing vagal tone. However, because neurodivergent people often have hyper-mobility and joint issues, be sure to be gentle with your body whatever kind of movement you decide to do.
Weight lifting has the added benefit of putting deep pressure on the joints, which many neurodivergent people find relaxing. Somatic movement is especially useful for healing trauma and relaxing the body in a mindful way. Dr. Sam Zoranovich is a queer and neurodivergent-affirming chiropractor and has many great resources for neurodivergent-friendly somatic movement exercises.
Mindfulness and Meditation
Contemplative practices have been shown to have many benefits to mental health. Not only is meditation linked to decreased brain inflammation, better memory, and increased ability to learn new information, but it is also linked to increased HRV and vagal tone. Specifically, mindfulness has the ability to activate the vagus nerve, especially when there is breathwork involved. As an added bonus, mindfulness practices can help to increase interoception (the ability to monitor internal states like hunger, thirst, sleepiness, etc.), which many Autistic people and ADHDers people struggle with.
Probiotics and Omega-3s
In what is called the gut-brain axis, researchers have shown there is a huge connection between gut health and mental health. Like how the vagus nerve is connected to organs like the heart, it is also deeply interconnected with the gut. It is, after all, responsible for digestion. Therefore, the gut and microbiome communicate with the brain via the vagus nerve, meaning, when the gut is stressed, so is the vagus nerve. By taking care of our gut with probiotics and omega-3s, we can, in turn, take care of our nervous system.
Laughter
Laughter really is the best medicine! Studies have shown that laughter stimulates the vagus nerve by inducing diaphragmatic breathing. Only about ten minutes of laughter per day is shown to have many health benefits. Try adding more comedy in your life or some intentional laughter meditation!
Humming, Chanting, and Singing
Chanting can be found in many cultures around the world, and for a reason! Humming, chanting and singing are very powerful ways of activating the vagus nerve. One study even showed that chanting “om” can deactivate the limbic center of the brain, which is responsible for threat and emotion. The Vagus nerve is interconnected with our vocal cords and the muscles at the back of the throat. Therefore, using your vocal cords in mindful ways directly activates this nerve.
Massage
Massage is another great way to increase vagal tone. Human contact is so important, and many of us are walking around touch starved. Mindful human-to-human contact both stimulates the vagus nerve and increases oxytocin, the bonding hormone. Although you can get this kind of massage from someone else, there are also ways to give yourself simple massages. This video by Sukie Baker is an excellent example.
Havening
Havening is a form of self-soothing by creating safety through comforting, therapeutic touch. Havening involves distinctive self-soothing touch that creates a haven for yourself. The theory rests on the idea that soothing touch boosts the production of serotonin. Serotonin has a soothing effect. Specific motions such as cupping your hands on your cheeks, holding a hand across your chest, or crossing your arms (as if giving yourself a hug) while striking your shoulders and upper arms. This creates a sense of safety and wellbeing through your touch (note many Autistic people have a preference for deep pressure, be sure and apply a pressure that feels good).
Relaxation Exercises
Last, but certainly not least, is relaxation exercises. Relaxation exercises are arguably the most important tool in our regulation toolbox. These exercises directly target the ventral vagal system to calm the body out of dysregulation. We can use them before bed, to ground ourselves in the morning, to recover for stressful events, or to more mindfully engage in conflict. These exercises can include a variety of breathing techniques, progressive muscle relaxation (PMR), and meditations.
Conclusion: the Autistic & ADHD Nervous System
Understanding our nervous system is an important part of learning how to regulate ourselves. In this article we’ve learned about the autonomic nervous system, which is a part of the peripheral branch of the nervous system. In a regulated body, the sympathetic and the parasympathetic nervous systems work together to skillfull adapt to stress and changes in the environment. However, when our nervous systems are rigid (have a small window of tolerance) because of neurodivergence or trauma, we can easily fall into dysregulation, characterized by hyperarousal and hypoarousal.
However, there is always hope for us. By learning about our own vagal tone and window of tolerance, then introducing exercises to increase vagal tone, we can grow our window of tolerance over time.
If you’ve found this information helpful and want more guidance, I have a workbook all about the neurodivergent nervous system with worksheets to help you better get to know yours. In the workbook, you’ll find the information in this article alongside guides and step-by-step worksheets so you can learn about your own window of tolerance and to begin to implement some of these regulation exercises in your daily routines. Get it here.