Evlo Fitness/Education/Body Composition/How to train your nervous system
Shannon Ritchey
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How to train your nervous system

Below is an excerpt from Fit Body, Happy Joints: Episode 109 “How to train your nervous system

When it comes to seeing the best results from your workouts, you don’t want to just train what you see (like muscles). You also want to train what you don’t see: your nervous system; the network of nerves and cells inside of you that are working behind the scenes to dictate how your body responds to and changes from exercise, how mobile you feel, how well you recover, and more. 

Historically, fitness programs have been one dimensional. They make you sweat and work “hard”, but don’t necessarily consider the most important part for seeing results. Namely, what’s happening behind the scenes. They pay no attention to how your brain, spinal cord, and complex network of nerves works and affects your body. 

Why this matters

If you are constantly grinding your body into the ground, you won’t be recovering from workout to workout. Eventually, you hit a wall where you aren’t really seeing yourself progress, you feel like you’re falling apart, and you may even start to experience mental/emotional side effects and sleep issues.

Ultimately, how you treat your body in your workout, and how you train (or don’t) train your nervous system can start to affect everything in your life. 

You might be testy with your partner because you’re always on edge, find that you can’t concentrate at work because you’re in a mental fog, or you realize you can’t sit on a plane because your back hurts. 

I want you to know that your workout is not one dimensional. It involves your muscles and your joints and your heart and lungs, of course. But we also have to consider how our nervous system is involved, and how we can use the tools we have available to create routines that consider how our body functions and operates as a whole. 

I want to talk about how the act of exercising itself affects your autonomic nervous system, what happens afterwards, how to know if you’re leaning too heavily in a sympathetic nervous system state, and tools to incorporate into your routine to improve the function of your nervous system and, therefore, your results. 

An overview of the nervous system

Your nervous system is a complex network that includes your brain, spinal cord, and nerves. It controls everything in your body from how fast your heart is beating to how easily you recover from workout to workout. 

Your nervous system is made up of two parts: your central nervous system (brain and spinal cord) and your peripheral nervous system (nerves that extend from the spinal cord and influence tissues like organs, muscles, etc). 

Both systems rely on each other to gather and assimilate information to take action in your body.

Within the peripheral nervous system, there is the autonomic nervous system. This is what we are going to focus on in this post. 

The autonomic nervous system

The autonomic nervous system is divided into the sympathetic branch and the parasympathetic branch. 

The sympathetic nervous system

The sympathetic branch (SNS) is the “fight or flight” branch that primes our body to run from or fight danger. 

Your body releases stress hormones like cortisol to increase heart rate, moves blood away from organs and towards the muscles so you can run or fight, and increases blood pressure and muscle tension. 

You may feel anxious, afraid, and “keyed up.” 

This is the “stress” side of your nervous system. When you are in a prolonged SNS state, you may eventually feel exhausted and burned out. More on this in a moment. 

The parasympathetic nervous system

The parasympathetic nervous system (PNS) is responsible for digestion and healing. 

In a PNS state, you may feel calm, at peace, and focused. This is also a place we want to be in social relationships where we are open and receptive and empathetic. Whereas in a SNS state, we may feel easily agitated, defensive, and on edge. 

Which state we are in is largely unconscious, but it is possible to shift from one state to another with practice and intention. This is “training” your nervous system, and can have huge payoffs on your results. 

The healing process post-exercise

Your nervous system is working behind the scenes in the hours and days following a strength workout.

This is important to understand so you can work with your body following a workout to make sure you’re recovering. If you aren’t recovering, you won’t progress. 

During the workout, the muscle fibers are damaged, which triggers an inflammatory response. After a strength workout, the muscles undergo a process of inflammation and repair.

The immune system sends immune cells to the damaged muscles to help remove debris and begin the repair process.

The inflammatory response

Inflammation gets a bad rep, but this acute inflammation and repair process is necessary for muscle growth and adaptation following a workout. It isn’t a bad thing unless it becomes chronic.

As the muscles heal and repair, they become stronger and more resilient. This is why it’s important to give your muscles time to rest and recover after workouts, as this allows the body to complete the repair process and adapt to the stimulus of the workout.

If you aren’t recovering, which happens with poor programing, chronic inflammation or inadequate recovery can have negative effects on muscle growth and overall health.

High levels of inflammation can lead to muscle breakdown, decreased immune function, and increased risk of injury. 

How does the nervous system step in

The nervous system plays a crucial role in regulating inflammation after a workout. 

In response to the muscle damage caused by exercise, the immune system releases inflammatory molecules called cytokines, which help to trigger the repair and growth process in the muscles.

When the sympathetic nervous system is activated, it can lead to an increase in cortisol and other stress hormones, which can trigger the release of pro-inflammatory cytokines. This can lead to increased inflammation and delayed recovery after a workout.

On the other hand, when the parasympathetic nervous system is activated, it can help to reduce inflammation and promote recovery. 

So constantly activating your SNS 7 days a week in your workout can lead to chronic inflammation, delayed healing, and ultimately worse results. 

This is why we breathe and relax following our workouts. Breathwork helps activate the PNS, which will ultimately kickstart the process of reducing inflammation and improving recovery.

For this same reason, we recommend 2 recovery days where you are walking and likely not spiking an SNS activation. 

Your body has the chance to “catch up” and heal any damaged tissue from the week so you can start your following week with a higher physical threshold.

How does the act of exercising affect your autonomic nervous system

The SNS gets a lot of heat. 

Activation of the SNS can be beneficial in the short term, but we don’t want chronic activation of the SNS. In our hustle-focused culture, many of us are constantly in this state due to our lifestyles (stressful job, family, endless to do lists), then layering overly-intense exercise on top. 

So SNS activation is not bad or wrong, but we want to balance stimulating the SNS and the PNS. 

Exercise can either activate your fight-or- fight or your rest/digest side of your nervous system, depending on the activity. 

How determine which part of your nervous system is activating

During high-intensity exercise, like sprinting or weightlifting, the sympathetic nervous system is typically more active.

The parasympathetic nervous system is generally more active during lower-intensity exercise like walking, yoga, sometimes Pilates, or even in some of our less systematically stressful classes like Barre.

Although this isn’t an exact science, you can guess whether your workout activated SNS or PNS based on a few clues: 

  • Heart rate: The sympathetic nervous system tends to increase heart rate, while the parasympathetic nervous system tends to decrease it. 
  • Breathing rate: The sympathetic nervous system tends to increase breathing rate, while the parasympathetic nervous system tends to decrease it. 
  • Sweat: The sympathetic nervous system activates sweat glands, so if you’re sweating heavily during exercise, it may be a sign that the sympathetic nervous system is more active.
  • Fatigue: If you feel like you got hit by a truck after your workout, that workout was likely a sympathetically-dominant activity. If you feel refreshed and relaxed and calm, that was more likely a parasympathetically-dominant workout

What types of workouts are associated with these responses?

The above can happen with any type of workout, and it will vary person-to-person. 

SNS activation is more likely to happen with HIIT/bootcamp/higher intensity cardio/lifting. 

But when it comes to strength training, you may see more or less activation of your SNS depending on the programming.

For instance, a workout that has lots of compound movements (think burpees or combination moves like squat to overhead presses or complex exercises involving lots of body parts) are more likely going to activate the SNS than a workout like an Evlo workout that is more focused on one muscle group at a time. 

This is because compound movements require a greater amount of exertion, which stimulates a stress response in your body. 

However, you can still activate the SNS in more targeted movements. If you are getting close to failure, like we recommend in our workouts, you are likely going to feel that SNS activating towards the end of your set. You may feel heart rate spike, you may start to sweat, your breathing rate may increase, etc. 

Again, it isn’t bad to activate your SNS, but it doesn’t need to upregulated the entire workout for your workout to be effective or a good use of your time. 

Is it necessary to consistently activate the sympathetic nervous system for results?

Many people associate an effective workout with one that increases SNS activity: breathing heavily, sweating, post-workout exhaustion, etc. This is why so many programs have these complex movements. And people buy them because they believe they are more effective. 

But stimulating the SNS for an hour straight is not necessary for results, and may be a piece of the puzzle that could lead to chronic SNS activation. Chronic activation of the SNS can be detrimental to muscle growth/recovery, and therefore your results. 

Impact of chronic SNS activation

Sympathetic activity will release stress hormones such as cortisol. 

Cortisol may promote and cause muscle breakdown and limit recovery. It can also inhibit other hormones, like testosterone, which promote muscle growth. Therefore, overactivation of the SNS can limit recovery and mean that while you’re putting in the work, you may not be seeing the linear results. 

It seems like the fitness industry is largely focused on the things that we think are necessary for results: sweating, calories, breathing heavy, total exhaustion.

But the best results come when our routine is focused on building muscle. Fat loss from exercise is minimal, which is something I went over in detail in episode #107 of Fit Body, Happy Joints on exercise and leanness. 

The most important factor in muscle growth and results from your workout is progressive overload, which means gradually increasing the intensity, volume, or frequency of your workouts over time. 

Activating the SNS with a hard, sweaty, complex workout is not a prerequisite for recruiting muscles adequately to stimulate growth, and thus, results from your workout.

Fitness industry conditioning and marketing

I rarely sweat during my workouts. I doubt I burn many calories. And yet I think I can say I’m in the best shape of my life. This is because I now focus on muscle over the calorie burn or mindless sweating.

Going to hour-long bootcamp classes every day may work for some people who have super athletic genetics and can recover quickly. But for most of the population, this is going to backfire and may eventually lead to chronic SNS activation. And all the while is completely unnecessary for fitness results. You can do a lot less and actually see better results while feeling better. 

But we are conditioned to believe that our workouts are not “enough” unless you have all those signs of SNS activation like sweatiness, fatigue, increased heart rate (which is used to calculate calories burned), etc. 

What really matters?

All that matters for results is that you loaded muscles adequately. If you’re choosing exercises that are mechanically loading the muscle you’re trying to target, and you’re taking that close to failure, you’re working towards muscle growth. That’s how to know you’ve done “enough”. Sweating, burning lots of calories, and fatigue can be correlated with a workout that satisfies that requirement. But if those signs aren’t there, it does not matter.

People scoff at our program thinking that it’s just for older people or for people who are injured. This is not the case! It’s truly for anyone who wants a more fit body and doesn’t want to destroy themselves in the process. Because the classes don’t unnecessarily spike your stress hormones and wear down your joints, but they are loading muscles enough to stimulate change. 

Here are some signs and symptoms that may indicate you are in a chronic state of SNS activation: 

  • Increased muscle tension
  • Constantly feeling tight/sore
  • Not seeing muscle growth (most likely due to impaired recovery) 
  • Fatigue
  • Reduced performance
  • Sleep issues 
  • Anxiety/depression/burnout

What if you are someone who feels like they’re in a chronic sympathetic nervous system state?

Take things down a notch. 

Maybe take out any cardio in your routine for a month. Focus on slow strength training with less complex movements that are less likely to activate your SNS. Bookend your workouts with the tools I’ll talk about in a moment. 

Obviously I’m biased, but I think the Evlo membership is perfect because you won’t lose any progress as far as muscle growth- you will actually likely gain muscle, especially if you’re pairing the workouts with the nutrition modules-and the classes are less stressful on your system. 

I know it’s scary, but if you’ve determined you may be experiencing burnout from chronic SNS activation and you’re afraid of gaining weight or losing progress by doing less, here’s my advice:

  1. Go listen to this episode of Fit Body, Happy Joints about exercise and fat loss. I think it will really reframe your thoughts around exercise and how building muscle may actually be more beneficial for you.
  2. Ask yourself if what you’re doing is sustainable. If you’re anything like I was, at some point you have to rip off the bandaid because your routine is unsustainable and the problems are going to begin to stack. So why not do it now and put yourself on a better path? I wish I would have done it sooner, and I know we hear that from our members all the time as well.

What I recommend doing is to catch yourself before you hit total burnout

Before you get to that chronic SNS activation state, you can start to measure your recovery and back off if you’re not recovering from week to week. 

There’s different ways to do this, one being a free tool that anyone can use at any time called the CO2 tolerance test.

This is a measure of your body’s ability to handle carbon dioxide (CO2) buildup, which is a marker of your ability to recover from intense exercise or stress. 

The theory behind this test is that if you have good CO2 tolerance, you are able to recover quickly from stress, exercise, or other physical demands. 

This is because CO2 tolerance is related to your body’s ability to regulate its stress response and activate the parasympathetic nervous system (the “rest and digest” system) for recovery.

How to perform this test

You’ll take 5 of your deepest breaths. On your 6th exhale, you’ll breathe out as long as you can. In general, if you can breathe out for longer than 25 seconds, you’re likely recovered. If you’re routinely hitting below that, it may be time to check in with your routine. You may also consider taking a Reset Week where you just walk or do some light movement to let your body catch up on its recovery processes. 

There is science to back reset weeks. They improve anabolic signaling that is responsible for healing muscle tissue. Do not worry about taking time off. Start with 4 days if you’re concerned. I can almost guarantee that you will come back stronger and move past a plateau. Listen here for more on reset weeks. 

We’ve now discussed the differences between PNS and SNS as far as exercise goes. Hopefully now you’re on board with balancing the SNS and PNS, and valuing your PNS activation for driving better results and for feeling better. 

How to train your autonomic nervous system

What’s really cool is that you can train your body to drop into a sympathetic or parasympathetic state faster and with more ease. Let’s talk about pre- and post-workout routines that can help you do this. 

If you’ve ever taken an Evlo class, you’ll see that we do pre- and post-workout breathwork and mobility. This isn’t woo-woo or meant to waste time. It will actually influence how your body performs in your workout and recovers after your workout. 

Let’s go into a little more detail on the science behind this.

Pre-workout: Active mobility and breathwork

Warming up isn’t just about increasing blood flow and physically increasing your body’s temperature, although those things are good, too.

A warm-up is also about priming your nervous system. Let’s start with breathwork in your warm-up.

Pre-workout breathwork

The goal is to optimize oxygen and carbon dioxide levels in the body to improve endurance, focus, and energy levels during the workout.

Studies have shown that pre-workout breathwork can improve performance and reduce fatigue during exercise by optimizing oxygen and carbon dioxide levels in the body. This can lead to increased endurance, better focus, and faster recovery after the workout. 

Should you focus on your inhale or exhale pre-workout? 

In short: longer inhale on the warm-up, and longer exhale on the cool-down. 

This is because the inhalation process involves the contraction of the diaphragm muscle and other accessory muscles, which leads to increased oxygen intake and activation of the sympathetic nervous system.

This activation can help to improve focus, energy, and alertness, which can lead to improved performance during your workout.

Again , you don’t need or want to avoid SNS activity altogether. This is more strategically and intentionally placing this technique into your workout in a way that will boost the workout’s effectiveness. 

Pre-workout mobility

Another thing we do in every Evlo class is pre-workout active mobility. Let’s get into what this is doing for your nervous system. 

This is more about the somatic nervous system which we will go over more next week. Let’s touch on this quickly because it’s related and interesting. 

Active mobility refers to the ability to move your joints through their full range of motion, using your own muscles. 

These exercises can improve your ability to connect to and contract the surrounding muscles during your workout. 

Arthrokinetic reflex

This happens via the arthrokinetic reflex. 

The arthrokinetic reflex occurs when a joint in the body is moved or manipulated. It is a type of proprioceptive reflex that helps to maintain stability and control over movement.

When a joint is moved, receptors in the joint capsule, ligaments, and muscles surrounding the joint are stimulated. 

This information is sent to the spinal cord and processed by the central nervous system. The arthrokinetic reflex is then activated, which causes the muscles surrounding the joint to contract and stabilize the joint.

Ultimately, this helps to improve neural activation in the muscles, leading to greater strength and power during physical activity.

Active mobility also increases proprioception, which can lead to improved balance, coordination, and overall movement quality.

In summary, pre-workout activities are not about stretching mindlessly or just doing some jumping jacks. A pre-workout routine should include taking 3-5 breaths, focusing on a long inhale using rib-cage breathing, and doing active mobility in each joint you plan to load to improve neuromuscular connection, stability, and therefore the quality of your workout.

Post-workout: Mobility & breathwork

A focus on the PNS is our goal in the cool down. And again, you will train your body to enter into a PNS state the more you practice. You can “train” your body to enter into a PNS state with more ease, and thus accelerate your recovery, improve the way you feel, and ultimately strengthen your results. 

At first, you may have a hard time relaxing. This is not necessarily a good thing, but it’s very normal and common. Our culture is very focused on productivity and hustle, so it’s no wonder we are balls of stress that have a hard time relaxing. 

But with practice, you will get better at it so be patient! One of my favorite testimonials is when I hear members say “I finally love savasana now”.

Why some may find this type of work harder than others

Some people may have a harder time relaxing because your ability to stimulate your PNS may be due to past experiences, how you were raised, etc. 

I’m not formally trained in psychology so I don’t want to get into this too much, but your past experiences have carved the neural networks that you live with today. 

Those neural networks are patterns and shortcuts that your brain uses to sense what’s going on around you and respond to keep you safe.  This isn’t to say you can’t change those neural networks with focused practice, but some people may have an easier time stimulating their PNS than others. 

Some people may require more practice and reps, while others may feel like it’s more or less second nature. Breathwork and taking care of yourself in your workout can make a big difference. But if you’re struggling to relax and stimulate your PNS, be patient with yourself. It will get better, and you may consider outside interventions like therapy. 

Although it is difficult and almost frustrating for some people, it’s so worth it. Because when you can better regulate your PNS, you can recover faster. When you can recover faster, you’ll see better results from your workout. This is why taking a holistic approach to fitness truly is the most effective route. 

Post-workout breathwork

During the cool-down, you want to focus on long exhales and really just doing less. I always say: let go of the rigidity, let your body move easily and fluidly. Don’t worry so much about perfect form. We are more trying to kickstart a PNS state. 

One of the ways that a longer exhale can stimulate the PNS is through the activation of the vagus nerve. The vagus nerve is a long nerve that runs from the brainstem through the neck and into the chest and abdomen. It is responsible for regulating heart rate, digestion, breathing, and more.

During exhalation, the diaphragm muscle relaxes, and the pressure in the chest decreases, allowing the vagus nerve to be stimulated. This stimulation can help to activate the PNS, leading to a decrease in heart rate and blood pressure, as well as a feeling of relaxation and calmness.

Effects of post-workout breathwork and mobility

Allowing yourself to have a few moments of relaxation and gentle movement post-workout is not only going to help you see better results, but it will truly lead to better longevity. 

You will feel more calm and energized and clear-headed after your workout instead of feeling frazzled and like you got hit by a truck and tanked your energy. Your joints will likely thank you because you will be better at clearing inflammation and recovering. 

Of course what you’re doing during your workout matters, but taking just a few minutes post-workout to breathe and move in easy, gentle ways can truly pay dividends both in the short term, and in the long term.


Let’s summarize everything we talked about today. 

Exercise will have an effect on your nervous system in many more ways than I talked about today. But you can use this peripheral understanding of the autonomic nervous system to monitor how you’re recovering, and ultimately, the results you’re seeing from your workouts. 

Some SNS activation is not bad, but we care more about muscle than we do about SNS activity. SNS activity is not required for muscle growth. 

Chronic SNS activity can be detrimental to results. Some symptoms include reaching plateaus/growing weaker, sleep issues, constant soreness/tightness, anxiety/depression/burnout, fatigue, and more.  

If you’re in a chronic burnout state, scale way back for a month, take out any intense cardio, and reassess. 

You don’t have to wait for your body to crash and burn. Monitor it as you go by using the CO2 tolerance test, or just based on subjective symptoms like fatigue, inability to “feel” muscles contract, etc. 

You can use breathwork and mobility to train your PNS and help accelerate recovery and results. 

In our next blog post, I’m going to get into some other fun aspects of the nervous system. Stay tuned!