Sympathetic Nervous System
The Sympathetic Nervous System (SNS) is often called our “fight or flight” system. It gets a bad rap because out modern world tends to activate it, but this system developed to keep us safe. Learning to understand the SNS—and how to shift out of it—can support mental clarity, reduce stress, and improve our overall well-being.
WHERE IS THE SYMPATHETIC SYSTEM?
The SNS is a team of nerves running down the middle and lower spine, from the thoracic to lumbar regions (T1 to L2).
On either side of the spine, the SNS has a line of relay stations called the sympathetic chain ganglia— kind of like a necklace of beads—the SNS sends messages from bead to bead, then out to nearly every major organ, ready to kick things into gear if needed.
HOW THE SNS WORKS: KEY PLAYERS AND THEIR ROLES
To make this easier to understand, let’s imagine a scenario: You’re lying in bed, cozy and calm, when suddenly you hear a suspicious sound outside. Maybe it’s just a neighbor rummaging in their car too late, or maybe it’s something worse. That’s when the SNS team springs into action!
Norepinephrine: Our first responder. Like the friend who shakes you awake the second they hear a strange noise, norepinephrine gets you up and moving. Your heart starts pounding as blood rushes to your muscles, your breathing quickens, and you’re suddenly alert, tuned into every sound. Norepinephrine gives you that initial jolt and sharp focus.
Epinephrine (Adrenaline): The backup powerhouse. Imagine norepinephrine as the alert that sends you to the window, while epinephrine gets you ready to react. Released from the adrenal glands, epinephrine amplifies everything: your pupils dilate, your heart pumps harder, your lungs open up for better breathing, and glucose floods your bloodstream to fuel fast action. Epinephrine preps your muscles so you can dash to the door or react quickly.
Cortisol: The long-haul strategist. If it turns out the noise was just the wind, your SNS should calm down quickly. But if the stress continues—let’s say you think you see a shadow at the window—cortisol steps in. It helps keep energy available and suppresses non-essential processes (like digestion), just in case you need to stay alert for longer.
Histamine: The sentry on high alert. Histamine heightens your sensitivity to surroundings, keeping you even more awake and aware. It’s why you may feel jittery or restless if you’re already on edge. In a way, histamine is like a lookout that helps “prime” the SNS, ready to call in cortisol for support if the tension persists.
EFFECTS OF PROLONGED SYMPATHETIC ACTIVATION
While this SNS team is crucial in moments of danger, they aren’t meant to be on high alert all the time. Chronic activation—feeling like you’re constantly “on”—can lead to health issues over time, from muscle tension to digestive trouble, and even mood imbalances. If you’ve ever felt worn out after a big scare or stressful period, that’s the SNS overstaying its welcome.
Prolonged activation of the SNS can lead to:
Poor Sleep: It’s tough to sleep soundly when your body thinks it needs to stay alert to protect you or solve a threat.
Muscle Tension: Staying on edge keeps your muscles tense, leading to discomfort and even headaches.
Digestive Issues: Blood flow shifts away from digestion, leading to indigestion or bloating.
Mood Imbalances: Prolonged activation depletes serotonin and dopamine, increasing irritability, anxiety, or even depression.
Blood Sugar Imbalances: Insulin suppression keeps blood sugar elevated, increasing the risk of metabolic issues.
Cardiovascular Risks: The strain of high blood pressure and heart rate can impact the heart over time.
Immune Suppression: Cortisol’s effects on immune function can make the body more vulnerable to infections.
BURNOUT AND HPA AXIS DYSREGULATION
Over time, prolonged SNS activation stresses the HPA axis (the hypothalamus-pituitary-adrenal connection), which manages our stress response. When this system gets taxed, we feel “burnt out,” mentally foggy, and physically fatigued. Other issues may arise as well:
Brain Fog: The HPA axis impacts the hippocampus, which is crucial for memory. When stressed, it’s harder to focus, remember details, or think clearly.
Reproductive and Thyroid Imbalance: Chronic stress can disrupt hormones, leading to irregular cycles, low libido, thyroid imbalances, and even fertility issues.
Electrolyte Imbalance: High cortisol affects adrenal hormones that regulate sodium and potassium, which can lead to fatigue and dizziness.
ACTIONABLE TIPS: HOW TO SHIFT OUT OF SYMPATHETIC MODE
To balance the SNS, we need to engage the parasympathetic system—the “rest and digest” part of the nervous system. Think of animals at a watering hole: after a quick scare, they return to their calm state. Here’s how to bring that same calm to your body:
Sound it Out:
Horse lips: Blowing air out of your lips like a horse or like a baby blowing a raspberry relaxes your body and relieves tension.
Hum or sing: Vibrating our vocal cords helps to activate our parasympathetic system.
Music Therapy:
Dance Party: Put on your favorite playlist and let yourself move. Dancing releases tension and stimulates feel-good endorphins, shifting you into a more relaxed, joyful state.
Listen & Unwind: Lie down, close your eyes, and listen to an album you love. Let the music help you connect to yourself, creating a peaceful, restorative break from stress.
Mindfulness:
Practice Stillness: Set a timer for 3-4 minutes. Place a hand on your chest, take deep breaths, and let go of the need to solve anything in that moment.
Anchor with Intention: Place your hand on the center of your chest and try saying, “I’m quieting my mind and just experiencing my vibration without thoughts.”
Gentle Movement: Light activities like walking or stretching can help release adrenaline without over-stressing the body, unlike high-intensity exercise (which just stimulate more cortisol production).
Sleep Hygiene: To wind down, turn off electronics an hour before bed, read with a soft light, or sip chamomile tea. Even taking melatonin (3mg, or 0.3mg in pregnancy) can balance cortisol levels and improve sleep quality.
Supportive Foods & Blood Sugar Balance:
Protein-Rich Breakfast and Slow Carbs at Night: Have protein in the morning to stimulate dopamine and complex carbs (like sweet potatoes or quinoa) in the evening to help you feel sleepy when you should be.
Magnesium-Rich Foods: Leafy greens, nuts, and seeds support relaxation. Avoid refined sugars and alcohol to reduce spikes in blood sugar and stress.
While the sympathetic system helps us rise to challenges and respond to threats, a balanced nervous system relies on our ability to return to a restful state. In the next post, we’ll explore the parasympathetic nervous system—the “rest and digest” branch—where calm, restoration, and healing take center stage.
What's coming:
The Autonomic Nervous System - The Intro
The Sympathetic Nervous System - "Fight or Flight"
The Parasympathetic System and the Vagus Nerve - "Rest & Digest"
The Enteric Nervous System - The Gut-Brain Connection
The Somatic Nervous System - Move & Sense
The Cranial Nerves - Pathways of Sensory and Motor Control
Brain Regions and Their Roles in Thought, Mood, and Movement
How the Nervous System Impacts Mental Health & Trauma Recovery
Craniosacral Therapy - Enhancing Nervous System Balance
Are there specific areas of the nervous system you're curious about? Drop a comment below, and I'll be sure to cover them as we journey through this incredible body-wide network!
