Nervous System Regulation: What It Actually Means to Feel Safe, Flexible, and Resilient

Your Nervous System Was Never Supposed to Be Calm All the Time

If you’ve spent any time in the wellness world lately, there is a reasonable chance someone has told you that you need to “regulate your nervous system.” Perhaps you’ve been encouraged to stimulate your vagus nerve, increase your heart rate variability, shake out stored stress, hum, sigh, breathe into your belly, splash cold water on your face, walk barefoot in the grass, or purchase something vaguely Scandinavian that promises to activate your parasympathetic nervous system. Some of those practices have legitimate physiological foundations. Some have evidence that is interesting but preliminary. Some have been stretched so far beyond the available science that the vagus nerve itself may be requesting a little nervous system regulation.

What gets lost in all of this is that nervous system regulation is a real and extraordinarily important biological process, but it doesn’t mean what social media sometimes makes it sound like it means. Regulation isn’t a special state we achieve when we’re sufficiently relaxed. It isn’t synonymous with activating the parasympathetic nervous system, and it certainly doesn’t mean remaining calm regardless of what is happening around us.

A well-regulated nervous system changes. It responds.

When something frightening happens, it mobilizes. When we exercise, heart rate and blood pressure adjust to meet increased metabolic demand. When we stand up, autonomic reflexes rapidly change cardiovascular activity so enough blood continues reaching the brain. When we eat, digestive processes shift. When we enter a competitive environment, give an important presentation, become sexually aroused, encounter someone we love, get into an argument, or hear a suspicious crash downstairs in the middle of the night, our physiology changes accordingly. Those changes aren’t evidence that regulation has failed. They are regulation.

The autonomic nervous system is continually adjusting internal physiology to meet changing circumstances, working alongside the endocrine system, immune system, cardiovascular system, respiratory system, digestive tract, and brain. Much of this occurs without our conscious participation because, thankfully, you don’t have to remember to adjust your blood pressure every time you stand up or manually instruct your stomach to begin digesting lunch. The body is continuously making thousands of small adjustments in the background while we’re busy thinking about considerably more important things, such as whether we remembered to move the laundry into the dryer.

When we talk about supporting nervous system regulation, then, we’re not trying to teach the body how to be calm. We’re talking about helping it maintain adaptability: the capacity to respond appropriately when circumstances change and to recover when the demand has passed. That distinction is subtle, but I think it’s one of the most important things to understand about stress, anxiety, and resilience.

Because sometimes the healthiest thing your nervous system can do is speed up. And sometimes the healthiest thing it can do afterward is recognize that it no longer needs to.

Meet the Autonomic Nervous System

The nervous system is enormous and beautifully complicated, but for our purposes, let’s begin with one part of it: the autonomic nervous system, or ANS. The ANS helps regulate functions that occur largely outside conscious control, including heart rate, vascular tone, digestion, sweating, pupil diameter, bladder function, and many aspects of breathing and metabolic regulation.¹

Traditionally, we describe two major branches of the autonomic nervous system: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic branch is often summarized as “fight or flight,” while the parasympathetic branch gets the considerably more appealing label “rest and digest.”

Those phrases are memorable, but they create a problem when we begin treating them as moral categories.

Sympathetic equals stressed.

Parasympathetic equals peaceful.

Therefore sympathetic equals bad and parasympathetic equals good.

Human physiology did not design itself according to this infographic.

The sympathetic nervous system participates in mobilizing resources when the body needs to respond to increased demand. Heart rate and cardiac contractility may increase, blood flow can be redistributed, pupils dilate, and metabolic fuels become more readily available.² These responses are useful during a genuine emergency, but they’re also useful when you’re running up a hill, competing in a sport, concentrating intensely, or standing backstage preparing to give a presentation. If I am kickboxing, I do not particularly want my nervous system prioritizing rest and digestion. I would like it to help me move.

Parasympathetic activity, meanwhile, contributes substantially to processes associated with recovery, digestion, energy conservation, cardiovascular regulation, and restoration. The vagus nerve, which we’ll get to shortly, carries a large proportion of parasympathetic fibers and plays an important role in communication among the brain, heart, lungs, and gastrointestinal tract.¹

But these systems don’t simply operate like a light switch in which one turns completely off when the other turns on. Autonomic control is dynamic, organ-specific, and considerably more complex. Sympathetic and parasympathetic influences can shift independently depending on what the body is trying to accomplish.³

This matters because people sometimes become worried that they are spending too much time “in sympathetic” or assume every increase in heart rate means their nervous system is dysregulated. That’s not how I want you thinking about your body. You need both branches. The more useful question is whether your nervous system can move between physiological states appropriately.

Fight, Flight, Freeze…and the Problem With Catchy Labels

You’ve probably also encountered the language of fight, flight, freeze, and fawn. These terms can be useful for helping people recognize different behavioral responses to perceived threat, particularly in trauma-informed settings. Fighting or fleeing are intuitive. Freezing describes a state in which movement or behavioral response may become inhibited. “Fawning” is generally used in psychological discussions to describe appeasing or accommodating behavior intended to reduce interpersonal threat.

Where I become cautious is when these descriptions are presented as though each corresponds to one simple, scientifically distinct autonomic mode that can be diagnosed from an Instagram graphic.

Defensive behavior is far more sophisticated than that. Neural circuits involved in threat detection and defensive responses interact with autonomic, endocrine, motor, sensory, cognitive, and emotional systems, and the response depends partly on the nature and proximity of the perceived threat.⁴ A person may become hypervigilant, flee, fight, become immobile, seek help, appease another person, or move through several responses over the course of one stressful event.

Human beings are not limited to four buttons. We also bring memory, context, personality, relationships, previous experiences, and conscious interpretation into the equation. Someone who becomes quiet during conflict isn’t necessarily “in freeze.” Someone who tries to make peace isn’t automatically “fawning.” Sometimes they’re simply choosing not to argue with Uncle Steve at Thanksgiving because they would like to eat pie in peace.

These frameworks become most helpful when they give us language for our experiences without becoming rigid diagnoses. The same applies to the word dysregulated.

What Does “Dysregulated” Actually Mean?

“Dysregulated” is another term that has escaped from clinical and scientific contexts and developed a remarkably busy life online. People now describe themselves as dysregulated because they’re tired, irritable, anxious, overwhelmed, having digestive symptoms, struggling to focus, sleeping poorly, craving sugar, procrastinating, scrolling on their phones, or simply having a terrible Tuesday.

Some of those experiences absolutely can occur alongside altered stress physiology or autonomic dysfunction. But “dysregulated nervous system” isn’t a single medical diagnosis, and it shouldn’t become a catch-all explanation for every uncomfortable human experience.

When I use the word regulation, I’m thinking more broadly about the body’s capacity to adjust physiological and emotional responses according to context. Healthy regulation involves both reactivity and recovery. We need to generate an adequate response when circumstances demand one, and then we need mechanisms capable of limiting that response and returning systems toward baseline.

Researchers often discuss this through the concept of allostasis, which describes the process of achieving stability through physiological change. Rather than trying to keep every internal variable perfectly constant, the body anticipates needs and adjusts accordingly. Cortisol rises and falls throughout the day. Heart rate changes when we exercise. Blood pressure adjusts when we stand. Metabolism changes after a meal. Immune activity increases during infection. These changes help maintain function in an unpredictable world.⁵

Problems can develop when those adaptive systems are repeatedly activated, fail to shut down efficiently, or become poorly matched to the demands being placed on them. Over time, the cumulative physiological burden of repeated adaptation is often described as allostatic load.⁵

This gives us a much more useful way to think about chronic stress. The problem isn’t that your body responds. The problem may be that it is responding too frequently, too intensely, for too long, or without adequate recovery between demands.

That distinction also explains why two people can live through apparently similar circumstances and experience them very differently. Their nervous systems aren’t starting from identical places. One person may be well rested, socially supported, financially secure, physically healthy, and facing a stressful event with considerable resources available. Another person may encounter the same event while sleep deprived, grieving, caring for a sick parent, dealing with chronic pain, struggling financially, and navigating hormonal changes. The stressor might look identical on paper. The load isn’t.

Your Body Is Constantly Asking, “What Does This Mean?”

One of the most fascinating shifts in neuroscience has been increasing recognition that the brain is not simply waiting passively for information and then reacting to it. It is continually interpreting incoming sensory information in light of previous experience and attempting to predict what those signals mean. This includes signals originating inside the body.

In last week’s discussion of anxiety, we introduced interoception, the process through which the nervous system senses and interprets internal physiological states such as heartbeat, breathing, gastrointestinal sensations, temperature, and muscular tension. Interoceptive processing contributes to emotional experience and appears particularly relevant in anxiety disorders, where internal sensations may receive heightened attention or threatening interpretations.⁶

Consider what happens when your heart suddenly beats faster. The sensation itself doesn’t arrive with a label attached. A faster heartbeat while you’re halfway through a workout may be interpreted as normal exertion. The exact same sensation while you’re sitting quietly at your desk could feel concerning. If you notice it immediately and think, Why is my heart racing? Something must be wrong, anxiety may increase sympathetic activation, which can increase your heart rate further. Your brain now receives an even stronger signal and may interpret that as confirmation that its original concern was justified. Nothing about the sensation was imaginary. The meaning assigned to it helped shape what happened next.

This is one reason nervous system regulation cannot be reduced to physiology alone. Our beliefs, expectations, memories, and interpretations influence how we experience bodily signals, while bodily signals simultaneously influence thoughts and emotions. The conversation moves in both directions.

So Where Does the Vagus Nerve Fit?

Ah, the vagus nerve. If cortisol was the wellness world’s favorite molecule a few years ago, the vagus nerve may currently be its favorite piece of anatomy. To be fair, it deserves some attention.

The vagus nerve, cranial nerve X, is a major component of the parasympathetic nervous system and travels from the brainstem through the neck into the chest and abdomen, communicating with structures including the heart, lungs, and gastrointestinal tract. Importantly, a substantial majority of vagal fibers are afferent, meaning they carry sensory information from the body toward the brain rather than simply transmitting commands from the brain to the body.⁷

I think that’s one of the most interesting facts about the vagus nerve because it reinforces something we’ve been discussing for months: the brain spends a great deal of time listening to the body.

The vagus participates in cardiovascular regulation, gastrointestinal function, respiratory processes, and communication involving immune and inflammatory pathways.⁷˒⁸ It is also one pathway through which the gut and brain communicate, which is why it appeared repeatedly during our August gut-health and September brain-health discussions.

Where things get fuzzy is when “supporting vagal activity” becomes “vagus nerve hacks.” Cold exposure. Gargling. Humming. Singing. Deep breathing. Yoga. Meditation. Massage. Social connection. Laughing. Splashing water on the face. Various devices placed around the ear or neck. These practices don’t all have the same evidence behind them, they don’t necessarily work through the same mechanism, and feeling relaxed after doing something doesn’t prove that you have successfully “toned your vagus nerve.”

There are legitimate medical forms of vagus nerve stimulation. Implanted vagus nerve stimulation has FDA-approved indications in conditions including treatment-resistant epilepsy and depression, and noninvasive forms of stimulation are an active area of research.⁹ That is very different from claiming that humming for thirty seconds resets the nervous system. Humming may feel good. Please hum. Just don’t make your vagus nerve carry the burden of explaining every pleasant sensation you experience afterward.

Polyvagal Theory: Useful Framework, Ongoing Debate

We also need to talk about polyvagal theory, because it’s almost impossible to discuss nervous system regulation online without encountering it. Developed by Stephen Porges, polyvagal theory proposes a hierarchical model of autonomic responses involving different vagal pathways and links these physiological states with social engagement, mobilization, and immobilization behaviors.¹⁰ The theory has had enormous influence in trauma therapy, psychotherapy, and popular discussions of nervous system regulation, particularly because it offers intuitive language for understanding why people may feel socially connected in some states, mobilized in others, or shut down under overwhelming threat.

Many people find this framework genuinely useful. However, some of its anatomical and evolutionary claims remain scientifically debated, and critics have challenged aspects of the proposed hierarchy, the distinction between vagal pathways, and interpretations of autonomic evolution.¹¹

I don’t think that means every therapeutic idea associated with polyvagal theory is worthless, nor do I think patients need to referee an academic debate before practicing a breathing exercise. But I do think we should distinguish between a useful conceptual framework and settled neurophysiology. This is an important theme in medicine generally. A model can help us understand an experience without being a perfect literal map of the underlying biology.

I use metaphors constantly when teaching patients. Your immune system isn’t actually an army. Your intestinal barrier isn’t literally a screen door. Your nervous system doesn’t truly have a gas pedal and brake pedal. Those comparisons help us organize complicated information, but problems arise when we forget that they are models and begin treating them as anatomical facts. Polyvagal language can be useful in exactly that way.

If thinking about “states of safety” helps someone recognize when their body is becoming activated and learn strategies for returning toward connection and recovery, wonderful. We simply don’t need to overstate the science to make the insight valuable.

Safety Is More Complicated Than Being Safe

One of the most compelling ideas within modern nervous system discussions is the distinction between objective safety and perceived safety. Your conscious mind can know that something is safe while your body remains activated. This happens constantly.

Someone can know intellectually that flying is statistically safe while experiencing intense fear on an airplane. A person who has been in a serious car accident may understand that the vehicle they’re riding in today is functioning perfectly and still notice their body tense when another car approaches quickly. Someone with panic disorder may understand exactly what a panic attack is while their nervous system continues responding as though something dangerous is happening.

Previous experiences influence prediction. The brain learns associations between circumstances and outcomes, particularly when those outcomes are emotionally significant. Fear conditioning research has demonstrated that previously neutral cues can acquire the ability to trigger defensive responses after being associated with aversive events, while extinction involves new learning that modifies how those cues are interpreted rather than simply erasing the original memory.¹² This helps explain why “But you’re safe!” isn’t always enough. The thinking brain may agree. Other networks have learned something different.

The great part is that the nervous system continues learning throughout life. Neuroplasticity allows neural circuits to change in response to repeated experiences, learning, therapy, behavior, and environmental input. That doesn’t mean deeply established patterns disappear because we repeat an affirmation three times in the mirror, but it does mean the nervous system isn’t permanently frozen at the moment something difficult happened. We can provide new experiences. We can build new associations. We can become better at tolerating sensations that once felt threatening. We can experience activation and discover that it resolves. We can learn that uncertainty doesn’t always end badly. Over time, the brain gets additional data.

Regulation Happens With Other People, Too

There’s another piece of nervous system health that our hyper-individualized wellness culture sometimes misses: we regulate in relationship with other people.

Humans are profoundly social animals. From infancy, physiological regulation develops in relationship with caregivers. Babies depend on adults not only for food and physical safety but also for help managing arousal, temperature, sleep-wake patterns, and emotional states. As we mature, we become increasingly capable of self-regulation, but we never stop being influenced by the people around us. Most of us know this intuitively.

Think about the difference between receiving frightening news alone and receiving it while someone you trust is sitting beside you. Consider how a calm clinician can change the experience of a frightening medical procedure, how the presence of a partner can make labor more tolerable, or how hearing the voice of someone you love can soften a difficult day.

This interpersonal influence is often described as co-regulation. Research examining social support and stress has repeatedly demonstrated that supportive relationships can influence psychological and physiological responses to stress, although the magnitude and mechanisms depend on context, relationship quality, and the type of support being offered.¹³

That last piece is important because technically being around other people isn’t automatically regulating. Anyone who has attended a contentious family gathering understands this. Relationships can create safety, and relationships can create threat. The nervous system notices the difference. This is one reason I hesitate when mental health advice focuses exclusively on what an individual should do to regulate themselves. Take a bath. Meditate. Journal. Breathe. Exercise. Fix your sleep routine. Optimize your morning. Those can all be valuable.

But sometimes a nervous system isn’t struggling because someone has failed to perform enough self-care. Sometimes they are lonely. Sometimes their marriage is deeply stressful. Sometimes they’re caregiving without support. Sometimes their workplace is genuinely unhealthy. Sometimes they don’t feel financially secure. Sometimes they’re experiencing discrimination, grief, chronic illness, or instability that cannot be breathed away.

We should be careful not to turn nervous system regulation into another way of asking individuals to adapt perfectly to circumstances that are legitimately difficult. Sometimes the environment needs to change too.

The Goal Is Not to Become Unbothered

I think this may be where nervous system conversations can become unexpectedly freeing. The goal is not to become the person who never reacts. I don’t particularly aspire to be “unbothered.” There are things in life that should bother us. There are situations that deserve anger, grief, fear, urgency, or action. If someone I love is in danger, I don’t want my nervous system to calmly observe that information while maintaining an immaculate resting heart rate.

Resilience isn’t emotional indifference. A flexible nervous system allows us to respond without becoming permanently trapped inside the response. This is where we return to the distinction between activation and recovery. Acute stress responses are not inherently harmful. Exercise temporarily increases sympathetic activity and stress hormones and yet, in an appropriate dose with adequate recovery, improves health. Difficult conversations may increase heart rate and emotional arousal while still being necessary for healthy relationships. Giving a speech may produce butterflies, sweaty palms, and a pounding heart without representing nervous system dysfunction.

The body isn’t failing because it responds. Sometimes the more important question is what happens afterward. Can the heart rate settle? Can the muscles release? Can attention widen again? Can digestion resume normally? Can you sleep? Can you stop replaying the conversation? Can you return to connection? Can your brain eventually receive enough evidence to recognize that this particular challenge is over? That ability to transition is much closer to what I mean when I talk about nervous system regulation.

And if you’ve spent years living under chronic stress, experiencing anxiety, caring for others, surviving trauma, pushing through exhaustion, or simply operating at a pace that rarely includes recovery, those transitions may not happen as easily as you would like. That doesn’t mean your nervous system is broken. It means it has adapted to the conditions it has repeatedly experienced. The interesting question is what happens when we begin changing those conditions.

Why Your Nervous System May Have Trouble Coming Back Down

Once we understand nervous system regulation as flexibility rather than permanent calm, the next question becomes much more interesting: why are some people able to move through a stressful experience and recover relatively quickly, while others remain activated for hours, lose sleep over it, replay the event the next morning, and still feel vaguely unsettled two days later?

Sometimes the answer is psychological. Sometimes it is physiological. Usually those categories aren’t nearly as separate as we’d like them to be.

The nervous system doesn’t respond to today’s stressor in isolation. It responds to today’s stressor while carrying information about everything else that is happening in the body and everything it has learned from previous experience. How well did you sleep last night? Have you eaten? Are you sick? Are you in pain? Are your hormones changing? Have you been under significant stress for six months already? Does this situation remind your brain of something that went badly before? Do you feel supported? Do you have any control over what is happening? Is there enough time between one demand and the next for your physiology to actually recover?

This is where the concept of allostatic load from Part 1 becomes much more tangible. A nervous system can be remarkably resilient under significant demand when there are adequate periods of recovery, but the equation changes when the demands keep arriving. One difficult week at work is different from two years in a job you dread. A few sleepless nights with a sick child are different from months of fragmented sleep. An occasional skipped meal is different from chronically under-fueling while drinking coffee to compensate for exhaustion. One argument with your spouse is different from living in a relationship where you never quite know when the next conflict will begin.

The body keeps adapting because that’s what it is designed to do. Eventually, however, adaptation itself becomes expensive.

Sometimes the Problem Isn’t the Stress. It’s the Lack of Recovery.

We tend to talk about chronic stress as though it simply means experiencing a lot of stressful events, but duration and recovery matter enormously. The body is built to tolerate fluctuations in demand. Exercise temporarily increases sympathetic activity, heart rate, catecholamines, and metabolic requirements, yet appropriately dosed exercise followed by recovery generally improves health. An intense workday doesn’t necessarily harm us. Neither does a difficult conversation, a hard workout, an argument, an exam, a deadline, or a night when the baby decides sleep is apparently an oppressive social construct.The trouble begins when the body has very little opportunity to transition out of demand before the next demand arrives.

This is one reason high-functioning people can be surprisingly difficult to identify as chronically stressed. They may still be accomplishing everything. They’re working, parenting, exercising, keeping appointments, responding to messages, making dinner, caring for other people, and generally appearing quite competent. Their ability to continue functioning becomes evidence, both to themselves and everyone around them, that they’re handling things well.Meanwhile, their physiology may be telling a somewhat different story.

Sleep becomes lighter. Digestion changes. Muscles remain tense. Headaches appear more frequently. Patience gets shorter. Libido disappears. Concentration becomes harder. Caffeine slowly migrates from enjoyable morning ritual to critical infrastructure. Small inconveniences begin producing disproportionately large emotional responses, and eventually someone finds themselves standing in the kitchen irrationally angry because the dishwasher was loaded incorrectly. It was probably not the dishwasher. It was the dishwasher plus the previous 147 things the nervous system had already managed that week.

This is one reason I want us to move away from asking whether someone “should” be able to handle a particular stressor. Stress tolerance isn’t a moral achievement. A person’s capacity at any given moment reflects the total resources available to them and the demands already being placed on those resources. What looks like an overreaction from the outside may make considerably more sense when we understand what else the system is carrying.

Sleep Changes the Brain You Bring Into Tomorrow

If I had to choose one foundational factor that consistently influences how resilient people feel, sleep would be very high on the list. Not because sleeping well magically solves life’s problems, but because sleep changes the brain that encounters those problems the following day.

Sleep and emotional regulation are tightly intertwined. Research has linked insufficient or disrupted sleep with changes in emotional reactivity, mood, attention to emotionally salient information, and the ability to regulate emotional responses.¹⁴ Sleep restriction can also influence autonomic and neuroendocrine stress systems, including sympathetic-adrenal activity and the HPA axis, although the exact responses vary depending on the degree and duration of sleep loss.¹⁵ More recent reviews continue to support a relationship between sleep physiology and both automatic and deliberate forms of emotional regulation.¹⁶

This probably isn’t surprising to anyone who has ever parented a newborn, traveled across multiple time zones, worked night shifts, or simply had insomnia for several nights in a row. Problems that would normally feel manageable suddenly feel enormous. Emotional bandwidth shrinks. We become more reactive and less patient, and the amount of effort required to respond thoughtfully instead of reflexively increases. Then stress can interfere with sleep. Now we have another feedback loop.

You have a stressful day, so you lie awake thinking about it. Poor sleep leaves you more emotionally reactive the following day, making the next stressor feel bigger. That increased stress makes it harder to sleep again. In susceptible individuals, stress-related sleep reactivity can contribute to persistent insomnia, and insomnia itself can become increasingly disconnected from the original event that started it.¹⁷

This is why I sometimes tell patients that sleep is not merely another item on their wellness checklist. It is part of the environment in which every other regulatory system is trying to function. It is also why I have very little patience for the idea that needing sleep reflects a lack of ambition. You cannot indefinitely productivity-hack your way around mammalian physiology. Eventually the mammal wins.

Your Nervous System Also Cares Whether You’ve Eaten

Another place where people sometimes mistake physiology for purely psychological anxiety is blood sugar regulation.The brain has substantial energy requirements and relies heavily on glucose under ordinary metabolic conditions. When blood glucose falls sufficiently, the body activates counter-regulatory mechanisms designed to restore it. Sympathetic nervous system activity and catecholamines participate in that response, and true hypoglycemia can produce adrenergic symptoms including palpitations, tremor, sweating, hunger, and anxiety.¹⁸ Those symptoms should sound familiar because they overlap considerably with the physical experience of anxiety.

This does not mean every afternoon episode of irritability or shakiness is clinical hypoglycemia. True hypoglycemia has specific diagnostic criteria, and in people without diabetes it deserves appropriate medical evaluation rather than casual self-diagnosis.¹⁸ But it does illustrate a broader principle: the nervous system is constantly responding to metabolic information, and some of the sensations generated by metabolic stress can resemble emotional anxiety.

In everyday practice, I pay attention to patterns. Someone tells me they feel inexplicably anxious at 3:00 every afternoon, and then I learn that breakfast is coffee, lunch sometimes happens at 1:30, and they have been running on adrenaline and good intentions since 7:00 a.m. That doesn’t prove blood glucose is the entire explanation, but it certainly gives us useful context. Sometimes people are trying very hard to meditate their way through a body that would also appreciate lunch.

This is why I prefer to think about nervous system regulation as something that emerges from overall physiological stability rather than something we accomplish exclusively through mental techniques. Regular nourishment, adequate protein, hydration, and a dietary pattern that supports relatively stable energy aren’t glamorous nervous system interventions, but they provide the body with one less reason to sound an alarm.

And for people who have become anxious about eating “perfectly,” I want to emphasize the word adequate far more than perfect. Turning every meal into a metabolic optimization project is not particularly regulating either.

Hormones Can Change the Volume

Hormonal transitions provide another beautiful example of why nervous system regulation isn’t purely psychological. Sex hormones interact with neurotransmitter systems, sleep, temperature regulation, cognition, and stress-responsive neural networks, so it isn’t surprising that some people notice meaningful changes in mood or anxiety during reproductive transitions. The important word there is some.

It would be easy to overstate this relationship and blame every emotional change in a woman on her hormones, which is both scientifically lazy and historically not a great look for medicine. Anxiety during the menopausal transition, for example, appears to be influenced by a complicated mixture of biological, psychological, sleep-related, vasomotor, and social factors rather than one straightforward estrogen-equals-anxiety pathway.¹⁹ More recent research continues to find associations among vasomotor symptoms, anxiety, and depressive symptoms while acknowledging that the direction and mechanisms of those relationships remain complex.²⁰ Clinically, though, I absolutely pay attention when someone tells me, “I’ve never felt like this before.”

Maybe she has always handled stress reasonably well, and suddenly in her forties she is waking at 3:00 a.m., experiencing heart palpitations, becoming more reactive, and feeling anxious in situations that previously wouldn’t have bothered her. That deserves curiosity. The answer may involve hormones, but it may also involve the sleep disruption caused by night sweats, changing family responsibilities, caregiving, career pressure, nutritional changes, thyroid function, or the cumulative reality of being a human being who has been responsible for everyone else for twenty years.

Likewise, pregnancy and the postpartum period can involve enormous shifts in reproductive hormones layered on top of physical recovery, disrupted sleep, new responsibilities, changes in identity, and sometimes feeding a small person around the clock while trying to remember whether you brushed your own teeth. Physiology and life experience arrive together. Trying to separate them perfectly is often less useful than understanding how they interact.

The Immune System Has a Seat at the Table

The immune system and nervous system are also in constant communication. Cytokines and other immune mediators can influence neural activity, behavior, sleep, appetite, energy, and mood, while the nervous system can influence immune responses through neuroendocrine and autonomic pathways. This bidirectional relationship is part of a rapidly evolving field sometimes described as psychoneuroimmunology, which is an impressively long word for the fairly intuitive idea that the brain and immune system talk to each other.

We experience this relationship very clearly during acute illness. When you have influenza, your desire to lie under a blanket, sleep, withdraw from social activity, and avoid running a 10K isn’t simply a personality change. Inflammatory signaling helps produce a coordinated collection of behavioral changes sometimes called sickness behavior, which encourages rest and conservation of resources while the immune system deals with a threat.²¹

Chronic low-grade inflammation is more complicated. Research has found associations between inflammatory markers and several psychiatric conditions, including subsets of depression and anxiety, but the relationship is heterogeneous.²² Not every anxious person is inflamed. Not every person with elevated inflammatory markers is anxious. And reducing mental health to “brain inflammation” is just another version of the single-cause storytelling we’ve been trying to avoid throughout this series. Still, it matters because it reminds us again that the nervous system responds to the internal environment.

If someone has an inflammatory illness, chronic infection, autoimmune activity, significant gastrointestinal inflammation, chronic pain, or another physiological process keeping immune signaling active, the nervous system is receiving that information. That doesn’t necessarily mean it is the cause of their emotional symptoms, but it may alter the background against which stress is experienced. The body doesn’t compartmentalize these conversations nearly as neatly as our medical specialties do.

The Gut Never Really Left This Series

At this point, I suspect some of you knew I was going to bring the gut back into the conversation. I promise I don’t receive a commission every time I mention the microbiome. But after spending August exploring gut health and September talking about the gut-brain axis, it would be strange to discuss nervous system regulation without acknowledging that the digestive tract is one of the largest sources of sensory information traveling toward the brain.

As I discussed earlier, much of the vagus nerve is afferent, carrying information from visceral organs toward the central nervous system. The gastrointestinal tract also communicates through endocrine signals, immune mediators, microbial metabolites, spinal pathways, and other mechanisms that collectively make up the microbiota-gut-brain axis.²³ What does this mean practically? It means gut health can influence the physiological environment in which the nervous system functions. It does not mean everyone with anxiety has dysbiosis. It does not mean a stool test can diagnose why someone feels emotionally dysregulated. And it definitely doesn’t mean we should start treating every difficult emotion with probiotics.

The research is fascinating, particularly around microbial metabolites, immune signaling, tryptophan metabolism, vagal communication, and stress responsiveness, but human studies are still working through questions of causality, individual variability, and which microbial patterns actually matter clinically.²³

What I find more immediately useful is remembering that gut-brain communication is bidirectional. Stress can alter gastrointestinal motility, secretion, visceral sensitivity, and digestive symptoms, while gastrointestinal discomfort itself can become a source of ongoing nervous system input. Someone with IBS who spends every commute worried about needing a bathroom isn’t experiencing a purely microbial problem or a purely psychological problem. The gut sensations create anxiety, anxiety influences gut function, and before long it becomes difficult to identify where the circle began. Sometimes circles don’t have useful starting points. We simply have to interrupt them somewhere.

Caffeine Is a Drug, Even When It Comes in a Cute Mug

We also need to talk about caffeine because this is one of those places where lifestyle and nervous system physiology collide in a particularly socially acceptable way. I enjoy coffee. This is not an anti-coffee newsletter disguised as a blog.

But caffeine is a psychoactive stimulant, primarily acting through antagonism of adenosine receptors, and it can increase alertness while also producing jitteriness, palpitations, sleep disruption, and anxiety in susceptible individuals, particularly at higher doses.²⁴ Individual responses vary substantially because of genetics, habitual consumption, dose, medications, pregnancy, liver metabolism, and baseline anxiety sensitivity.

This is where the context matters again. The cup of coffee that feels delightful after a good night’s sleep and breakfast may feel very different when consumed on an empty stomach after five hours of sleep during an already stressful week. Yet when people feel exhausted and overwhelmed, caffeine is often the tool they use to continue functioning at the same pace. Now we’re borrowing energy from tomorrow to meet today’s demands.

The same pattern can happen with alcohol in the opposite direction. Someone feels chronically activated, so a glass of wine in the evening becomes the quickest way to “turn the brain off.” Alcohol may initially feel sedating, but it can disrupt sleep architecture and contribute to sleep fragmentation later in the night.²⁵ The following day begins with poorer sleep, which may increase fatigue and emotional reactivity, which makes caffeine more appealing, and suddenly the nervous system is being pharmacologically pushed in one direction in the morning and another direction at night. I’m not saying everyone needs to abandon coffee and wine and live on filtered water while staring peacefully at a fern. I’m suggesting that if your nervous system feels perpetually activated, it is worth noticing what you’re asking it to compensate for.

Movement Is Stress, and That’s Part of Why It Helps

Exercise creates another apparent contradiction because physical activity temporarily activates many of the same systems we’re supposedly trying to “calm down.” Heart rate rises. Sympathetic activity increases. Catecholamines change. Cortisol may increase depending on intensity and duration. Breathing accelerates. Metabolic demand increases.

And yet regular physical activity is consistently associated with broad physical and mental health benefits and may improve stress resilience and symptoms of anxiety for many people.²⁶ How can both things be true? Because regulation isn’t the avoidance of physiological stress. It is the ability to adapt to stress and recover.

Exercise gives the body a controlled physiological challenge followed by recovery. Over time, cardiovascular, metabolic, muscular, and autonomic systems adapt to that challenge. This is hormesis in a very practical sense: an appropriate dose of stress can make the system more capable of handling future demand. The words appropriate dose matter enormously.

A restorative walk and a two-hour high-intensity training session are not interchangeable nervous system interventions. Someone sleeping eight hours, eating adequately, and training for an athletic goal may thrive on vigorous exercise. Someone sleeping five hours, under-eating, caring for a sick parent, working sixty hours a week, and dragging themselves through intense workouts because they were told exercise reduces cortisol may be adding another demand to a system that desperately needs recovery. I love exercise. I also love recovery. The body requires both.

This is another reason generic wellness prescriptions frustrate me. The question isn’t simply, “Is exercise good for stress?” The better question is, “What kind of movement does this particular body have the capacity to adapt to right now?” Sometimes the answer is lifting heavy things. Sometimes it’s a long walk with the dog. Sometimes it’s yoga. Sometimes it’s dancing badly in the kitchen while making dinner. All movement counts, and the nervous system does not award extra credit for suffering.

Trauma Changes Prediction, but Not Every Stress Response Is Trauma

No discussion of nervous system regulation would be complete without talking about trauma, particularly because the word has become tightly linked with “dysregulation” in popular wellness culture.

Trauma can absolutely alter the way the nervous system responds to cues associated with danger. Post-traumatic stress disorder involves changes in fear learning, threat appraisal, memory, arousal, avoidance, and other processes that can persist long after the original danger has passed. Research on fear conditioning and extinction demonstrates that the nervous system can learn associations between previously neutral cues and threatening outcomes, and those associations may later produce defensive responses even in objectively safer circumstances.²⁷ But I also think we should resist labeling every unpleasant experience as trauma.

A stressful day isn’t necessarily trauma. Feeling uncomfortable during conflict isn’t automatically a trauma response. Being nervous before public speaking doesn’t mean your nervous system is carrying unresolved trauma around PowerPoint presentations. Language matters because when every stress response becomes trauma, we risk pathologizing normal human adaptation and diluting the meaning of experiences that genuinely overwhelm a person’s capacity to cope.

At the same time, trauma doesn’t need to fit someone else’s definition of “bad enough” before it deserves care. What matters clinically is the impact an experience had on the person and whether patterns of hyperarousal, avoidance, intrusive memories, dissociation, or other symptoms continue interfering with life.

For people with significant trauma histories, nervous system regulation may require far more than lifestyle changes. Trauma-focused psychotherapy and other evidence-based treatments can help the brain develop new associations and reduce symptoms, and this work is often best done with trained professionals rather than attempted through a collection of nervous system hacks found online.²⁸ Sometimes the body needs support. Sometimes the story needs somewhere safe to go. Usually those things are connected.

The Nervous System Learns From Repetition

This may be the most hopeful piece of the entire discussion. The nervous system is plastic. It changes in response to repeated experience. That means repeated stress can shape it, but repeated experiences of recovery can shape it too. Fear can be learned, but new associations can be learned. A person can become increasingly sensitive to certain bodily sensations, but they can also become less afraid of those sensations through appropriate exposure and experience. Someone can spend years believing rest is unsafe or unproductive and gradually learn that stopping does not cause the world to collapse.

This doesn’t happen because we intellectually command the nervous system to change. It happens because we give it new data. You experience a racing heart during exercise and learn that the sensation isn’t dangerous. You have a difficult conversation and discover that the relationship survives. You set a boundary and realize the consequences aren’t as catastrophic as your brain predicted. You allow an unfinished task to remain unfinished overnight and discover that civilization continues into the morning. You feel anxiety rise, don’t immediately escape from it, and eventually experience it falling again. The brain notices. Not consciously in every case, but learning is happening.

This is part of why effective psychotherapy often involves more than talking about why we feel a certain way. Approaches such as cognitive behavioral therapy and exposure-based therapies can create structured opportunities to challenge predictions, experience feared sensations or situations safely, and build new associations over time.²⁹ The goal isn’t to convince yourself that nothing bad will ever happen. That would simply be another attempt at certainty. The goal is learning that you have more capacity to respond to uncertainty than your nervous system may currently believe.

Regulation Is About Capacity, Not Perfection

When I step back from all of this physiology, the picture that emerges is considerably more compassionate than the version of nervous system regulation we sometimes encounter online. Your nervous system is not a badly behaved machine you need to optimize.

It is continuously adapting to sleep, nutrition, hormones, immune signals, gut sensations, relationships, memories, medications, stimulants, physical activity, work demands, environmental conditions, and the thousand ordinary events that make up a life. Sometimes those inputs make regulation easier. Sometimes they make it harder. This is why I don’t want someone reading this article and immediately creating a seventeen-point nervous system routine.

Please don’t turn regulation into another thing you have to do perfectly. If anything, the work often begins by reducing the number of demands rather than adding more interventions. Maybe the body needs more sleep. Maybe lunch needs to happen before 3:00 p.m. Maybe five cups of coffee is not currently helping. Maybe the workout needs to be gentler this week. Maybe the relationship needs a boundary. Maybe the workload is genuinely unreasonable. Maybe a medical issue deserves evaluation. Maybe anxiety needs professional treatment. Maybe the nervous system has been doing an extraordinary job adapting to circumstances that have simply asked too much of it for too long.

The question isn’t, “How do I force myself into parasympathetic mode?” The question I find much more useful is:

What would give this nervous system a little more capacity?

That answer will look different for different people, and it will probably change across seasons of life. The practices that support someone during a relatively peaceful year may not be enough during grief, postpartum recovery, illness, caregiving, menopause, financial strain, or a major transition. Regulation is dynamic because life is dynamic.

And now that we understand some of the factors that influence our capacity to regulate, we can finally get practical. In Part 3, we’ll look at what actually helps: breathing and heart rate variability, movement, sleep, mindfulness, nature, sensory input, social connection and co-regulation, therapy, and some of the popular vagus nerve techniques that have kernels of legitimate physiology buried beneath considerably more enthusiastic marketing. No nervous system reset required. We’re going to work with the one you already have.

What Actually Helps a Nervous System Become More Flexible?

By this point, we’ve spent a fair amount of time talking about what nervous system regulation is, what it is not, and why some people have a much harder time moving out of a state of activation than others. We’ve also established that the nervous system is not a light switch, the vagus nerve is not a magic reset button, and your body is not failing because it occasionally responds dramatically to difficult circumstances. So what do we actually do with all of that?

The first thing I would say is that nervous system regulation is rarely about finding one perfect intervention. It is much more about building a physiological environment in which recovery becomes easier and more familiar. That usually happens through repeated, relatively ordinary experiences rather than one dramatic breakthrough. Sleep improves. Meals become more consistent. The body moves regularly. Breathing becomes slower when stress rises. Relationships feel safer. Therapy changes how certain triggers are interpreted. The workload becomes more realistic. A medical issue gets treated. A person becomes better at noticing activation without immediately assuming something is wrong. None of these things is particularly flashy. That is probably why social media has tried so hard to make them more exciting.

There is a whole world of “nervous system hacks” that promises rapid regulation through cold plunges, tapping, humming, shaking, ear stimulation, breathwork, sensory tools, or increasingly elaborate routines that begin to look suspiciously like a second job. Some of those practices can be useful. Some may influence autonomic physiology in meaningful ways. Others may simply feel calming because they are pleasant, rhythmic, grounding, distracting, or associated with a sense of control. I’m not against any of that. I just don’t want people to lose sight of the bigger picture. A nervous system becomes more resilient through repetition, not because you performed the correct sequence of techniques on Tuesday at 7:15 a.m.

Breathing Gives Us a Way Into the System

Breathing is one of the most interesting places to begin because it sits at the intersection of automatic and voluntary control. You will continue breathing without thinking about it, thankfully, but you can also change the pattern intentionally. That gives us a direct way to influence physiology.

Slow breathing practices have been associated with changes in heart rate variability, respiratory sinus arrhythmia, baroreflex sensitivity, and parasympathetic activity, although the magnitude and mechanisms depend on the technique, pace, and individual.³⁰ The most consistent effects tend to occur with slower, comfortable breathing rather than dramatic or forceful inhalations.

This distinction matters because “take a deep breath” is not always good advice if someone interprets that as repeatedly pulling in huge breaths. Over-breathing can lower carbon dioxide levels and worsen symptoms such as dizziness, tingling, chest tightness, or lightheadedness, which can be especially unhelpful for someone already prone to panic.

The goal is usually gentler. Slower. More comfortable. And often, a slightly longer or unhurried exhalation.

There is something deceptively simple about this, but I think that is part of its value. You do not need equipment. You do not need to be in a quiet room. You do not need to understand your vagal tone. You can use breathing while sitting in traffic, waiting for a difficult appointment, standing backstage, lying in bed, or before responding to an email you probably should not answer while irritated.

That last one is particularly useful. Breathing does not make the problem disappear. It changes the state in which you meet the problem.

Heart Rate Variability Is Useful, but It Is Not a Grade

Heart rate variability, or HRV, has also become tightly associated with nervous system regulation. HRV refers to the variation in time between consecutive heartbeats, and higher resting HRV is often associated with greater parasympathetic influence and cardiovascular adaptability, although interpretation is highly context dependent.³¹ In research settings, HRV can provide valuable information about autonomic regulation. In consumer wellness devices, it can also create a new avenue for people to become anxious about being anxious. I have mixed feelings about this.

Wearable technology can be incredibly helpful for noticing patterns. You may discover that alcohol consistently lowers your overnight HRV, that poor sleep changes recovery metrics, or that travel, illness, or heavy training alters your baseline. That information can be useful.

But HRV is influenced by age, fitness, sleep, hydration, illness, medications, menstrual cycle, training load, breathing, and countless other variables. A lower number one morning does not mean your nervous system is broken. It means the number is lower that morning. This sounds obvious, but health-tracking technology has a way of turning physiological variation into a performance score. People begin waking up, checking the app, and allowing a recovery number to tell them how they feel before they have even gotten out of bed. That is not the direction I want us going. Use data to increase awareness. Do not use data to outsource your relationship with your own body.

Movement Can Teach the Body That Activation Is Safe

Exercise is one of the most interesting nervous system tools because, as we discussed in Part 2, it temporarily increases physiological activation. Heart rate rises. Breathing gets faster. Muscles work harder. Sympathetic activity increases. And yet regular movement can improve stress resilience, mood, sleep, cardiovascular function, and symptoms of anxiety in many people.³²

Part of what I love about exercise is that it gives the nervous system repeated experiences of activation followed by recovery. You feel your heart pound, your breathing intensify, your muscles burn, and then the session ends. Your heart rate comes down. Breathing slows. The body recovers.

For someone who is afraid of bodily sensations associated with anxiety, this can be particularly meaningful because exercise creates many of the same sensations in a safe context. In fact, interoceptive exposure, a therapeutic technique used in panic treatment, intentionally recreates feared bodily sensations so the brain can learn that those sensations are tolerable and not inherently dangerous.³³ This does not mean everyone should exercise harder. Sometimes more intensity is exactly what a stressed nervous system does not need.

A person who is well rested and adequately nourished may thrive on vigorous training. Another person who is sleep deprived, under-eating, inflamed, and already physiologically overloaded may benefit more from walking, gentle resistance work, mobility, swimming, or restorative movement. Movement is medicine in the broadest sense. Dose still matters.

Sleep Is Still Doing More Work Than Almost Anything Else

I realize we have already talked about sleep, but it deserves another appearance because so many nervous system interventions become considerably less effective when someone is chronically sleep deprived. Sleep supports emotional regulation, memory consolidation, metabolic health, immune function, and recovery.³⁴ It also influences how reactive the brain is to emotionally significant stimuli and how effectively prefrontal regions regulate those responses.³⁵ In other words, sleep changes the brain that is trying to regulate itself the next day. This is why nervous system work that ignores sleep sometimes feels like trying to mop the floor while the sink is still overflowing.

If someone is waking repeatedly, going to bed far too late, dealing with untreated sleep apnea, drinking alcohol close to bedtime, experiencing severe hot flashes, or lying awake for hours with insomnia, I am going to care about that before I care whether they are humming correctly. Sometimes the highest-value nervous system intervention is not glamorous. It is treating the thing that is ruining sleep.

Mindfulness Can Help, but It Is Not Mandatory

Mindfulness and meditation are frequently recommended for anxiety and stress, and there is reasonable evidence that structured mindfulness-based interventions can reduce symptoms of anxiety and improve stress-related outcomes for some people.³⁶ I like mindfulness. I also think we should stop pretending everyone enjoys it.

Some people feel better when they sit quietly and observe their thoughts. Others become more aware of every uncomfortable sensation in their body and leave the session wondering why anyone thought this was relaxing. That does not mean they failed meditation. It means the intervention may need to be adapted.

Mindfulness is ultimately about attention and awareness, not achieving a blank mind. Walking can be mindful. Cooking can be mindful. Gardening can be mindful. Prayer can be mindful. Stretching can be mindful. Sitting on the porch without a phone can be mindful. The nervous system does not require you to own a meditation cushion. The larger skill is learning to notice what is happening without immediately reacting to every signal. That is particularly important in anxiety, where thoughts and sensations can quickly become interpreted as evidence of danger. Mindfulness practices may help create a small amount of space between the experience and the response. Sometimes that space is enough to make a different choice.

Nature Helps in Ways We Are Still Learning to Understand

Time in nature is another intervention that sounds almost too simple, but research increasingly supports associations between exposure to natural environments and improvements in stress, mood, attention, and physiological markers.³⁷ Maybe it’s because the forest emits a mysterious anti-cortisol frequency. Or maybe humans evolved in environments that looked very different from fluorescent offices, traffic, constant notifications, and screens that deliver emotionally provocative information twenty-four hours a day. Nature changes sensory input. The visual environment is different. Sound is different. Movement is different. Light exposure is different. The demands on attention are different.

For many people, simply being outside also means they are walking, disconnected from work, away from devices, or spending time with someone they care about. All of those things matter. This is another reason I prefer not to isolate one mechanism too aggressively. Maybe the walk in the park helps because of movement, light exposure, reduced screen use, social connection, attentional restoration, or some combination of all of them. If the result is that you feel better and there is minimal downside, I am comfortable letting several mechanisms share the credit.

Sensory Input Matters More Than We Realize

The nervous system is constantly receiving information through vision, sound, touch, smell, movement, and internal bodily signals. Changing that sensory environment can sometimes change the state of the system. This is why some people find weighted blankets calming. Others prefer warm showers, massage, music, rhythmic movement, soft lighting, stretching, or deep pressure. These practices do not all work through the same pathway, and evidence varies depending on the intervention and population. The common thread is that sensory input can influence arousal and attention.

This is also why overstimulation matters. Bright lights, loud environments, crowded spaces, constant notifications, multitasking, and endless digital input can all increase the number of signals the nervous system is processing at once. Sometimes regulation is not about adding something soothing. It is about removing something stimulating. Turn off the notifications. Leave the room. Dim the lights. Stop checking the news every twelve minutes. Close the laptop. This is not avoidance when the input is unnecessary. It is editing. And most nervous systems benefit from a little editing.

Co-Regulation Is Not a Wellness Trend

One of the most powerful regulators of human physiology is another human being. Supportive social connection can buffer stress responses, influence HPA-axis activity, and change how threatening an experience feels.³⁸ This makes intuitive sense because our nervous systems developed in relationship. Infants cannot regulate independently. They rely on caregivers for warmth, feeding, soothing, and protection. As adults, we gain much more capacity for self-regulation, but we do not become biologically independent from the people around us. A calm friend changes a difficult moment. A safe partner changes how a stressful day feels. A trusted clinician can reduce fear during a medical procedure. A supportive community can make grief more tolerable.

This is not weakness. It is physiology. There is a particular kind of modern wellness culture that quietly suggests the ideal human being should be able to self-regulate through anything. If you are triggered, breathe. If you are overwhelmed, meditate. If you are stressed, journal. If you are lonely, work on yourself. Sometimes that is appropriate. Sometimes the nervous system needs another person. We are allowed to borrow steadiness from each other.

Therapy Can Change the Predictions the Nervous System Makes

Psychotherapy belongs firmly in any serious discussion of nervous system regulation because the nervous system is not only responding to present-moment physiology. It is responding to learned associations, beliefs, expectations, and memories. Cognitive behavioral therapy, exposure-based approaches, trauma-focused therapies, and other evidence-based interventions can help people change the way they interpret and respond to internal and external cues.³⁹

Exposure therapy is especially interesting from a nervous system perspective because it does not work by convincing the brain that nothing bad can ever happen. It works by creating new learning. A person experiences the feared situation or sensation. The catastrophic prediction does not occur, or they discover they can tolerate the discomfort. The brain receives new data. Repeated enough times, that new learning can weaken the dominance of the old threat association. This is neuroplasticity in action. Not motivational-poster neuroplasticity. Actual learning. And it is one reason I think therapy can be deeply physiological even when no one is drawing a diagram of the autonomic nervous system. The brain is changing how it predicts.

Medications Can Be Part of Regulation Too

Medication sometimes gets left out of nervous system conversations because it does not fit the aesthetic. Breathwork looks natural. Medication looks medical. But the nervous system is biology, and medications can be an appropriate part of treatment. For some people with anxiety disorders, depression, trauma-related disorders, or other psychiatric conditions, medication can reduce symptom intensity enough that sleep improves, therapy becomes more effective, daily functioning returns, and the nervous system is no longer operating in a constant state of alarm.⁴⁰

That does not mean medication is always the answer. It means it can be one answer. I am far more interested in whether an intervention helps the person in front of me than whether it fits neatly into a philosophical category. Sometimes someone needs therapy. Sometimes medication. Sometimes both. Sometimes medical contributors need evaluation. Sometimes the environment itself needs to change. The best care is usually the care that actually matches the person.

Maybe Your Vagus Nerve Need a Regular Spa Day

We should probably come back to the vagus nerve one more time because by now it may feel neglected. Many popular practices marketed as “vagus nerve stimulation” are also activities that may influence autonomic state more broadly. Slow breathing, singing, humming, yoga, cold facial exposure, and social connection may all have physiological effects, and can support vagal stimulation.

Medical vagus nerve stimulation is a specific intervention with specific indications and parameters.⁴¹ That distinction matters because it’s the difference between a medical procedure and daily practices you can do to “tone” your vagus nerve, the same way they might train a muscle. Know, let’s keep in mind that the vagus nerve is not sitting around getting lazy because you forgot to gargle this morning. It is working, constantly. If humming feels good, hum. If singing makes you feel better, sing. If splashing cold water on your face helps interrupt a spiraling moment, that may be useful. Sometimes something helps because it helps and that is enough of a reason to do it.

Regulation Often Begins With Less

One of the biggest mistakes I see in nervous system work is adding more and more practices to a life that is already overloaded.

• Morning breathwork.
• Cold plunge.
• Meditation.
• Supplements.
• HRV tracking.
• Evening journaling.
• Stretching.
• Red light therapy.
• Three different apps.

Now the person who was stressed because they had too much to do has acquired nine additional tasks in the name of reducing stress. I am not convinced this is progress. Sometimes nervous system regulation is subtraction. Fewer obligations. Fewer notifications. Less caffeine. Less doomscrolling. Fewer workouts when the body is already exhausted. Less time with people who reliably leave you depleted. Less pressure to optimize every part of your life.

This is not glamorous. It is often extremely effective. The nervous system does not care whether your routine looks impressive. It cares whether the demands are manageable.

Recovery Has to Be Repeated to Become Familiar

One of the ideas I want to leave you with is that recovery itself is something the nervous system learns. If you have spent years operating under constant demand, rest may initially feel uncomfortable. Silence may feel strange. An empty calendar may feel suspicious. You may sit down and immediately remember six things you should be doing. This does not mean rest is bad for you. It means productivity has become familiar.

The nervous system often prefers familiar over objectively better. Repeated experiences of recovery can gradually change that. You finish work and do not reopen the laptop. You take a walk without listening to a podcast. You eat lunch away from your desk. You leave a task unfinished until tomorrow. You say no to something that would overload the week. You go to bed even though the kitchen is not perfect. Nothing catastrophic happens. The brain receives new information. Again and again. Over time, rest becomes less threatening. That is nervous system regulation too.

Resilience Is Not Unlimited Tolerance

I also want to be very clear about what resilience is not. Resilience does not mean becoming better at tolerating impossible circumstances forever. There is a point at which the appropriate response to chronic stress is not another coping strategy. The job may need to change. The relationship may need a boundary. The schedule may need fewer commitments. The body may need medical care. The person may need help.

There is a tendency to celebrate highly resilient people because they can keep going through extraordinary amounts of stress. Sometimes that is admirable. Sometimes it is simply evidence that someone has become very skilled at ignoring their own limits. I am familiar with that skill. Many high achievers are. We keep functioning because we can. Until eventually the fact that we can becomes the reason everyone assumes we should. Capacity is not infinite. And respecting that limit is not failure. It is regulation.

Your Nervous System Is Not a Project to Finish

If there is one thing I hope you take away from this entire article, it is that your nervous system is not a project you need to complete. There is no final state in which you become perfectly regulated and never feel anxious, overwhelmed, angry, exhausted, reactive, or uncertain again. That would not be health. That would be something closer to emotional anesthesia.

A healthy nervous system responds. It mobilizes when something matters. It protects us when something feels threatening. It changes with sleep, hormones, illness, relationships, seasons, grief, joy, exercise, and everything else that comes with being alive. The goal is not to stop those shifts. The goal is to build enough flexibility that the system can move. Up when it needs to. Down when it can. Toward connection when connection is available. Toward rest when the demand has passed. And toward help when the load has become too heavy to carry alone.

That is the version of nervous system regulation I want us talking about. Not perfect calm. Not a hacks-and-gadgets arms race. Not one more thing to do correctly.

Flexibility.

Capacity.

Recovery.

And perhaps most importantly, permission to stop fighting the fact that your body responds to life. It is supposed to. The work is learning how to help it come home afterward.

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References

1. Wehrwein, E. A., Orer, H. S., & Barman, S. M. (2016). Overview of the anatomy, physiology, and pharmacology of the autonomic nervous system. Comprehensive Physiology, 6(3), 1239–1278. https://doi.org/10.1002/cphy.c150037
2. Goldstein, D. S. (2010). Adrenal responses to stress. Cellular and Molecular Neurobiology, 30(8), 1433–1440. https://doi.org/10.1007/s10571-010-9606-9
3. Berntson, G. G., Cacioppo, J. T., & Quigley, K. S. (1991). Autonomic determinism: The modes of autonomic control, the doctrine of autonomic space, and the laws of autonomic constraint. Psychological Review, 98(4), 459–487. https://doi.org/10.1037/0033-295X.98.4.459
4. Kozlowska, K., Walker, P., McLean, L., & Carrive, P. (2015). Fear and the defense cascade: Clinical implications and management. Harvard Review of Psychiatry, 23(4), 263–287. https://doi.org/10.1097/HRP.0000000000000065
5. McEwen, B. S. (2000). Allostasis and allostatic load: Implications for neuropsychopharmacology. Neuropsychopharmacology, 22(2), 108–124. https://doi.org/10.1016/S0893-133X(99)00129-3
6. Paulus, M. P., & Stein, M. B. (2010). Interoception in anxiety and depression. Brain Structure and Function, 214(5–6), 451–463. https://doi.org/10.1007/s00429-010-0258-9
7. Breit, S., Kupferberg, A., Rogler, G., & Hasler, G. (2018). Vagus nerve as modulator of the brain-gut axis in psychiatric and inflammatory disorders. Frontiers in Psychiatry, 9, 44. https://doi.org/10.3389/fpsyt.2018.00044
8. Pavlov, V. A., & Tracey, K. J. (2012). The vagus nerve and the inflammatory reflex: Linking immunity and metabolism. Nature Reviews Endocrinology, 8(12), 743–754. https://doi.org/10.1038/nrendo.2012.189
9. Johnson, R. L., & Wilson, C. G. (2018). A review of vagus nerve stimulation as a therapeutic intervention. Journal of Inflammation Research, 11, 203–213. https://doi.org/10.2147/JIR.S163248
10. Porges, S. W. (2007). The polyvagal perspective. Biological Psychology, 74(2), 116–143. https://doi.org/10.1016/j.biopsycho.2006.06.009
11. Grossman, P. (2023). Fundamental challenges and likely refutations of the five basic premises of the polyvagal theory. Biological Psychology, 180, 108589. https://doi.org/10.1016/j.biopsycho.2023.108589
12. Milad, M. R., & Quirk, G. J. (2012). Fear extinction as a model for translational neuroscience: Ten years of progress. Annual Review of Psychology, 63, 129–151. https://doi.org/10.1146/annurev.psych.121208.131631
13. Hostinar, C. E., Sullivan, R. M., & Gunnar, M. R. (2014). Psychobiological mechanisms underlying the social buffering of the hypothalamic-pituitary-adrenocortical axis: A review of animal models and human studies across development. Psychological Bulletin, 140(1), 256–282. https://doi.org/10.1037/a0032671
14. Palmer, C. A., & Alfano, C. A. (2017). Sleep and emotion regulation: An organizing, integrative review. Sleep Medicine Reviews, 31, 6–16. https://doi.org/10.1016/j.smrv.2015.12.006
15. Meerlo, P., Sgoifo, A., & Suchecki, D. (2008). Restricted and disrupted sleep: Effects on autonomic function, neuroendocrine stress systems and stress responsivity. Sleep Medicine Reviews, 12(3), 197–210. https://doi.org/10.1016/j.smrv.2007.07.007
16. Straus, L. D., Ten Brink, M., Sikka, P., Srivastava, R., Gross, J. J., & Colvonen, P. J. (2024). The role of objective sleep in implicit and explicit affect regulation: A comprehensive review. Neurobiology of Stress, 31, 100655. https://doi.org/10.1016/j.ynstr.2024.100655
17. Kalmbach, D. A., Anderson, J. R., & Drake, C. L. (2018). The impact of stress on sleep: Pathogenic sleep reactivity as a vulnerability to insomnia and circadian disorders. Journal of Sleep Research, 27(6), e12710. https://doi.org/10.1111/jsr.12710
18. Rayas, M. S., & Salehi, M. (2023). Non-diabetic hypoglycemia. In K. R. Feingold et al. (Eds.), Endotext. MDText.com, Inc.
19. Bryant, C., Judd, F. K., & Hickey, M. (2012). Anxiety during the menopausal transition: A systematic review. Journal of Affective Disorders, 139(2), 141–148. https://doi.org/10.1016/j.jad.2011.06.055
20. Gordon, J. L., Rubinow, D. R., Eisenlohr-Moul, T. A., Xia, K., Schmidt, P. J., & Girdler, S. S. (2021). Efficacy of transdermal estradiol and micronized progesterone in the prevention of depressive symptoms in the menopause transition: A randomized clinical trial. JAMA Psychiatry, 75(2), 149–157.
21. Dantzer, R., O’Connor, J. C., Freund, G. G., Johnson, R. W., & Kelley, K. W. (2008). From inflammation to sickness and depression: When the immune system subjugates the brain. Nature Reviews Neuroscience, 9(1), 46–56. https://doi.org/10.1038/nrn2297
22. Costello, H., Gould, R. L., Abrol, E., & Howard, R. (2019). Systematic review and meta-analysis of the association between peripheral inflammatory cytokines and generalised anxiety disorder. BMJ Open, 9(7), e027925. https://doi.org/10.1136/bmjopen-2018-027925
23. Cryan, J. F., O’Riordan, K. J., Cowan, C. S. M., Sandhu, K. V., Bastiaanssen, T. F. S., Boehme, M., et al. (2019). The microbiota-gut-brain axis. Physiological Reviews, 99(4), 1877–2013. https://doi.org/10.1152/physrev.00018.2018
24. Lara, D. R. (2010). Caffeine, mental health, and psychiatric disorders. Journal of Alzheimer’s Disease, 20(Suppl. 1), S239–S248. https://doi.org/10.3233/JAD-2010-1378
25. Ebrahim, I. O., Shapiro, C. M., Williams, A. J., & Fenwick, P. B. (2013). Alcohol and sleep I: Effects on normal sleep. Alcoholism: Clinical and Experimental Research, 37(4), 539–549. https://doi.org/10.1111/acer.12006
26. Stubbs, B., Vancampfort, D., Rosenbaum, S., Firth, J., Cosco, T., Veronese, N., Salum, G. A., & Schuch, F. B. (2017). An examination of the anxiolytic effects of exercise for people with anxiety and stress-related disorders: A meta-analysis. Psychiatry Research, 249, 102–108. https://doi.org/10.1016/j.psychres.2016.12.020
27. Milad, M. R., & Quirk, G. J. (2012). Fear extinction as a model for translational neuroscience: Ten years of progress. Annual Review of Psychology, 63, 129–151. https://doi.org/10.1146/annurev.psych.121208.131631
28. Watkins, L. E., Sprang, K. R., & Rothbaum, B. O. (2018). Treating PTSD: A review of evidence-based psychotherapy interventions. Frontiers in Behavioral Neuroscience, 12, 258. https://doi.org/10.3389/fnbeh.2018.00258
29. Craske, M. G., Treanor, M., Conway, C. C., Zbozinek, T., & Vervliet, B. (2014). Maximizing exposure therapy: An inhibitory learning approach. Behaviour Research and Therapy, 58, 10–23. https://doi.org/10.1016/j.brat.2014.04.006
30. Zaccaro, A., Piarulli, A., Laurino, M., Garbella, E., Menicucci, D., Neri, B., & Gemignani, A. (2018). How breath-control can change your life: A systematic review on psycho-physiological correlates of slow breathing. Frontiers in Human Neuroscience, 12, 353. https://doi.org/10.3389/fnhum.2018.00353
31. Shaffer, F., & Ginsberg, J. P. (2017). An overview of heart rate variability metrics and norms. Frontiers in Public Health, 5, 258. https://doi.org/10.3389/fpubh.2017.00258
32. Stubbs, B., Vancampfort, D., Rosenbaum, S., Firth, J., Cosco, T., Veronese, N., Salum, G. A., & Schuch, F. B. (2017). An examination of the anxiolytic effects of exercise for people with anxiety and stress-related disorders: A meta-analysis. Psychiatry Research, 249, 102–108. https://doi.org/10.1016/j.psychres.2016.12.020
33. Craske, M. G., Treanor, M., Conway, C. C., Zbozinek, T., & Vervliet, B. (2014). Maximizing exposure therapy: An inhibitory learning approach. Behaviour Research and Therapy, 58, 10–23. https://doi.org/10.1016/j.brat.2014.04.006
34. Walker, M. P., & van der Helm, E. (2009). Overnight therapy? The role of sleep in emotional brain processing. Psychological Bulletin, 135(5), 731–748. https://doi.org/10.1037/a0016570
35. Goldstein, A. N., & Walker, M. P. (2014). The role of sleep in emotional brain function. Annual Review of Clinical Psychology, 10, 679–708. https://doi.org/10.1146/annurev-clinpsy-032813-153716
36. Khoury, B., Lecomte, T., Fortin, G., Masse, M., Therien, P., Bouchard, V., Chapleau, M. A., Paquin, K., & Hofmann, S. G. (2013). Mindfulness-based therapy: A comprehensive meta-analysis. Clinical Psychology Review, 33(6), 763–771. https://doi.org/10.1016/j.cpr.2013.05.005
37. Twohig-Bennett, C., & Jones, A. (2018). The health benefits of the great outdoors: A systematic review and meta-analysis of greenspace exposure and health outcomes. Environmental Research, 166, 628–637. https://doi.org/10.1016/j.envres.2018.06.030
38. Hostinar, C. E., Sullivan, R. M., & Gunnar, M. R. (2014). Psychobiological mechanisms underlying the social buffering of the hypothalamic-pituitary-adrenocortical axis: A review of animal models and human studies across development. Psychological Bulletin, 140(1), 256–282. https://doi.org/10.1037/a0032671
39. Carpenter, J. K., Andrews, L. A., Witcraft, S. M., Powers, M. B., Smits, J. A. J., & Hofmann, S. G. (2018). Cognitive behavioral therapy for anxiety and related disorders: A meta-analysis of randomized placebo-controlled trials. Depression and Anxiety, 35(6), 502–514. https://doi.org/10.1002/da.22728
40. Bandelow, B., Michaelis, S., & Wedekind, D. (2017). Treatment of anxiety disorders. Dialogues in Clinical Neuroscience, 19(2), 93–107. https://doi.org/10.31887/DCNS.2017.19.2/bbandelow
41. Johnson, R. L., & Wilson, C. G. (2018). A review of vagus nerve stimulation as a therapeutic intervention. Journal of Inflammation Research, 11, 203–213. https://doi.org/10.2147/JIR.S163248

October 6, 2026