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How Does the Body Respond to Dangers?

The importance of knowing your nervous system.

The autonomic nervous system is our internal surveillance system, pursuing safety while remaining alert for danger. The system guides our daily experiences, making sure that we survive in moments of danger and thrive in times of safety. When we receive cues of danger we react, and when we receive cues of safety we relax.

The autonomic nervous system doesn’t make a judgment about good or bad (Porges, 2011). It simply acts to manage risk and seek safety. Personal perception, not the actual facts of experience, creates a response. So it is important to bring awareness to our nervous system.

The autonomic nervous system is composed of two parts. The sympathetic system deals with fight-flight-freeze reactions. The sympathetically triggered state brings strategies of confrontation, avoidance (or immobilization) in an attempt to resolve the danger. In the event that we are unable to successfully overcome (or escape) the threat, the system will automatically shut down (fainting in extreme cases, and emotional numbness in a milder form) to preserve life. The parasympathetic system acts as a “brake” on sympathetic arousal to reduce activation and facilitate relaxation. The balance between the two systems is a key step toward greater health and wellness.

During stress (e.g., performance anxiety) the sympathetic nervous system dominates the parasympathetic system. For example, if we are trapped in a situation or pressed for time, we might experience a spike in sympathetic activation in the form of a fast heartbeat, tense muscles, and a sense of hypervigilance. In a sympathetically triggered state, we misjudge cues, such as neutral faces appear angry and the world is an unfriendly place. After solving the problem, our heart and breathing rate return to normal, our bodies relax, and our awareness of our surroundings softens.

Porges (2011) coined the term neuroception—detection without awareness. Neuroception describes the way our autonomic nervous system scans for cues of safety and danger without involving thinking part of our brain. Neuroception colors our experiences and creates an autonomic response. For example, in a conversation with a friend, the autonomic nervous system recognizes not just the words themselves, but the rhythm of the voice (e.g., intensity), facial expression, and body posture. Neuroception is listening beneath the words for sounds of safety and friendship.

Early experiences shape our neuroception. Once the learning habit has been formed, stimuli similar to original may evoke the conditioned response. For example, a person growing up with an overly abusive and critical father has a chronic attitude as fear of authority figures and is always careful to get everything right. He acts as if he were a helpless child. Thus, it is important to bring awareness to neuroception, and to interrupt habitual response.

Thriving demands the capacity for inhibition of a survival response (Dana, 2018). We are social beings needing reliable and cooperative relationships in our daily living experiences. We feel in our bodies the ways caring, and being cared for, provide physical and emotional well-being. When we feel lonely, we also feel unsafe, and loneliness activates the survival systems.

Positive emotion can build enduring resources. Experience of positive emotions can help calm a nervous system in survival mode and can improve the balance between sympathetic and parasympathetic systems. For example, enjoying music can help to relieve stress and improve our mood by the release of "feel-good" chemicals in the brain.

Finally, behaviors that stimulate the parasympathetic system can offset the arousing and taxing activity of the sympathetic nervous system. For example, deep or diaphragmatic breathing exercises involved in yoga and meditation activate the body’s parasympathetic nervous system.


Dana Deb (2018) The Polyvagal Theory in Therapy: Engaging the Rhythm of Regulation. W. W. Norton & company.

Porges, S. W. (2011). The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-Regulation. 1st Edn. New York, NY: W. W. Norton.