Chronic Pain and the Nervous System: Understanding Your Body

Chronic pain is more than just what hurts. Chronic pain and the nervous system are closely connected, influencing your immune system, hormones, digestion, sleep, how you respond to stress, and your overall health. Understanding how these areas connect can help you understand why chronic pain affects the whole body and why improving your health requires looking beyond your symptoms.

How Chronic Pain Changes the Nervous System

The nervous system is how your body communicates and how you feel everything. It receives information, processes it, and sends messages between your brain, spinal cord, organs, muscles, and nerves. All the sensations you feel, including pain, travel through this complex system. That is why the relationship between chronic pain and the nervous system is so important. It is mainly divided into two complex parts.

Watch the video below: It can help you better understand how chronic pain and the nervous system are connected.

Now that you have an understanding of the functions of the nervous system, you can understand the difference in how interconnected chronic pain, the nervous system, and your body are. This brings a whole new understanding between acute and chronic pain, how sensitization can begin, how the brain and pain are connected, how the fight or flight response comes in, and why pain can be so easy to trigger.

The Sympathetic and Parasympathetic Nervous Systems

The sympathetic nervous system is known as our fight-or-flight system. This system tells our body that we are in danger and how our body needs to respond to that danger.

The parasympathetic nervous system is known as the rest and digest system. This system relaxes us after the body’s response to danger. It also does the following:

• Slows down your heart rate.
• Stimulates your digestion by increasing stomach acid.
• Helps with urination by controlling your bladder muscles.
• Constricts your pupils.
• Promotes relaxation.
• The Vagus Nerve is part of it.

The Vagus Nerve is one of the main nerves of the Parasympathetic Nervous System and controls specific body functions such as digestion, heart rate, the immune system, mood, fight-or-flight responses, speech, taste, and skin sensations. When the Vagus nerve responds, it is usually an unpleasant experience that is often triggered by stress, pain, and fear.

The vagus nerve also plays a significant role in pain perception and originates in the brainstem. When stimulated, it can actually help to reduce pain signals sent to the brain, making it a potential target for treating chronic pain conditions; essentially, activating the vagus nerve can have a pain-inhibiting effect by influencing the brain circuits involved in pain processing. We will share how you can do this later on in the article.

How Your Brain Processes Pain

• The brain decides what it means. It doesn’t just receive the signal; it interprets it and deciphers how much it hurts, where it hurts, and how you feel about it, which is why stress, fear, and fatigue can turn the volume up on pain, even without a new injury. It also evaluates your response, like screaming or crying, which comes from the Limbic System, an area of the brain associated with feelings.

The brain can keep the “pain signal” turned on even after the tissues heal, which is why supporting nervous system health, not just healing the injured body part, becomes an important part of long-term pain management.

The Neuro-Immune-Endocrine Connection

Your nervous, immune, and endocrine (hormone) systems constantly communicate with one another. Together, they influence inflammation, stress hormones like cortisol, immune activity, and pain perception.

When there is further danger, as well as current pain, this signaling can become frequent or constant, creating a recipe for chronic or ongoing pain. All of these systems are constantly communicating and are involved in managing stress, the production of cortisol, inflammation levels, and how our immune system signals. That is why fully managing the whole body can be helpful when managing chronic pain.

Inflammation, Gut Health, and Chronic Pain

Inflammation, gut health, and chronic pain are linked through the autonomic nervous system and the gut-brain axis, and it is driven by your gut microbiome.

• Inflammation and Nerve Sensitization: These inflammatory signals circulate throughout your body. This rise in inflammation can also increase the body’s perception of pain. This often leads to normal activities feeling more uncomfortable. When the nervous system becomes persistently overresponsive, this plays a role in central sensitization and more widespread pain.
• Immune Response: When the immune system identifies these toxins and leaked particles, they are interpreted as invaders and are attacked, releasing inflammatory proteins known as cytokines.
• Nutrient Absorption & Intestinal Permeability: When the gut microbiome becomes out of balance and the intestinal wall weakens, it disrupts your body’s ability to absorb nutrients and can lead to issues like “leaky gut”. That is why diet is so important for managing pain.

This is a complex network. The autonomic nervous system, hypothalamic-pituitary-adrenal (HPA) axis, and nerves within the gastrointestinal tract all link the gut and the brain, allowing the brain to influence intestinal activities, including the activity of functional immune effector cells. The gut also influences mood, cognition, and mental health via this communication network. It is also the gut-brain axis that is linked to leaky gut & autoimmune disorders. For more information, read our article on Gut Health, Inflammation, and Pain.

Balancing the Nervous System

Balancing your nervous system and relaxing the vagus nerve are important factors in managing chronic pain. Living with chronic pain tends to keep you in the fight-or-flight mode, and focusing on balancing these two systems can return you to the rest-and-digest mode.

There are many things you can do to promote balance; they include the following:

• Deep breathing utilizing the Box Breathing technique, which engages the parasympathetic nervous system (rest and digest).
• Getting regular gentle movement daily. Walking, water aerobics, tai chi, or yoga.
• Create a meditation routine.
• Spending time outdoors, sitting counts.
• Maintain or create social connections.
• Get a massage.
• Focus on eating a healthy anti-inflammatory diet.

Activities that can increase vagus nerve activity to promote relaxation include:

• Laughing & Humming
• Splashing your face with cold water
• Massaging your outer ear
• Sensate Relaxation Device

Please remember that these activities will not eliminate chronic pain overnight, but when practiced consistently, they can help by creating a healthier balance between the sympathetic (“fight or flight”) and parasympathetic (“rest and digest”) nervous systems. Over time, these small habits can support resilience and improve overall well-being.

Sleep and Recovery

Sleep is super important when trying to manage pain because poor sleep has a cycle all its own, making it an important part of understanding chronic pain and the nervous system. Quality sleep helps calm the nervous system, regulate inflammation, support tissue repair, and improve pain tolerance.

The most common path is:

If you have trouble sleeping, focus on creating a sleep schedule and balancing your nervous system with the techniques mentioned above.

My Perspective

In my experience, understanding how the body interprets pain and how these systems work together helps take away some of the fear that chronic pain creates. The more you understand what is happening in your body, the better equipped you are to support your overall health and make informed decisions about your care.

Key Takeaways

• Chronic pain affects the entire body, not just the area that hurts.
• The nervous, immune, digestive, and endocrine systems work together.
• Small daily habits can help support nervous system balance.
• Looking beyond symptoms helps improve long-term health and overall well-being.

For more information on managing chronic pain, visit our Living with Chronic Pain Learning Center.