What Is Your Autonomic Nervous System (ANS)? 

Part one: on understanding the autonomic nervous system (ANS)

What is the ANS?

Think of it as the automatic part of the nervous system that functions behind the scenes of our awareness. Its role in the body is to regulate things like temperature, hormone levels, blood supply, and blood sugar without any conscious input from us. It’s always working to keep us alive and in balance, adjusting our internal state in response to the world around us.

The Two Main Branches of the ANS

1. Sympathetic Nervous System (SNS) – This is your accelerator. It prepares the body to respond to danger by increasing your heart rate, blood sugar, and alertness. This is commonly referred to as the “fight or flight” (or sometimes “freeze”) response.

2. Parasympathetic Nervous System (PNS) – This is your brake. It helps you rest, digest, and recover. Once a threat has passed, this system slows things down so your body can return to balance and heal.

In a healthy, responsive nervous system, these two systems work like a well-coordinated dance activating and relaxing in rhythm with your life’s demands. But chronic stress, trauma, or emotional overwhelm can cause the system to become stuck. When your sympathetic system is always “on,” it’s like having your foot jammed on the gas pedal. This leads to burnout, poor sleep, impaired digestion, difficulty concentrating, and a general sense of unease.

But There’s More: Enter the Polyvagal Theory

To deepen our understanding of the ANS, Dr. Stephen Porges’ Polyvagal Theory introduces a third, more nuanced view of how our body responds to the world - not just with acceleration or braking, but with different levels of safety, stress, and shutdown.

According to the theory, the nervous system has three main states:

1. Ventral Vagal (Safe and Social):

When you’re in this state, you feel calm, connected, open, and present. Your body is at ease and able to digest, heal, and relate to others.

2. Sympathetic (Fight or Flight):

You feel anxious, tense, restless, irritable, or overwhelmed. Your energy is mobilised to escape danger - real or perceived.

3. Dorsal Vagal (Shutdown or Freeze):

This is a collapse state. You might feel numb, disconnected, exhausted, hopeless, or disengaged. It’s the body’s last-resort survival mechanism.

These states operate on a ladder, and you can move up or down depending on your environment, thoughts, memories, and even posture or tone of voice - things your body picks up on even before your mind is aware.

A Simple First Step

Try this today:

Take one full minute to pause. Place a hand on your heart or belly. Breathe slowly, letting the exhale be longer than the inhale. Gently notice how your body feels - tense, relaxed, numb, energised, sleepy? No judgment - just curiosity.

This small act of noticing begins to rewire your nervous system. When you recognize your current state, you gain the power to shift it.