Collection Four: Polyvagal Theory and Autonomic Science

Your Autonomic Nervous System Is Not Simply On or Off

Why sympathetic and parasympathetic processes can interact rather than behaving like a single switch.

Article #063·● Published·8 min read·Foundational

Definition

The autonomic nervous system is often described as a two-position switch between sympathetic (“on”) and parasympathetic (“off”). In reality, the two branches interact continuously, sometimes activating together, and their effects vary by organ, timing, and context.

Why it matters

Binary framings mislead patients about what is happening in their own bodies. A more accurate picture supports more accurate self-observation.

The Science

Sympathetic and parasympathetic activity can co-occur; their effects on the same organ can be additive, competing, or context-dependent. The classic “fight or flight” model captures only a fraction of autonomic behavior.

The NSI Perspective

NSI teaches autonomic states as a landscape, not a light switch. This precision honors the science and clarifies the experience.

Clinical Implications

Clinicians can help patients see multiple simultaneous processes rather than forcing every experience into a single mode.

Practical Application

When you feel activated, ask which parts of you are activated and which are quiet. The answer is rarely uniform, and the specificity is useful.

References

  1. 1.Berntson GG, Cacioppo JT. Handbook of Psychophysiology. Cambridge; 2016.