Our nervous system has three states – and why this is crucial for health

The autonomic nervous system is often described in classical teaching as a balance between the sympathetic (“stress response”) and parasympathetic (“relaxation”) systems. This model is helpful, but in its simplification it falls short.

The Polyvagal Theory, developed by Stephen Porges, expands this understanding and shows that the parasympathetic system in particular must be viewed in a more differentiated way. It describes three clearly distinguishable states of the nervous system that influence emotional experience as well as central physical functions – from cardiovascular regulation to immune activity.

THE THREE STATES OF THE NERVOUS SYSTEM

1.    Ventral vagal state (safety and regulation)

This state is part of the parasympathetic system – this is where the organism is in balance. It stands for safety, social connectedness, and inner stability. Put simply: you feel calm, present, and socially connected to other people.

Physiologically, it creates optimal conditions for regeneration, healing processes, and a well-functioning immune system.

2.   Sympathetic state (activation)

Here the sympathetic system predominates. This state corresponds to the classic stress response. The body mobilizes energy, heart rate and alertness increase – the organism is geared toward performance, fight, or flight.

In the short term, this reaction is useful and necessary. It becomes problematic when it continues chronically.

3.   Dorsal vagal state (withdrawal and energy conservation)

This state also belongs to the parasympathetic system, but it differs clearly from the ventral vagal branch. Under prolonged overload, the nervous system can shift into a state of reduced activity.

Here, the organism responds with withdrawal, reduced activity, and energy conservation. This state often manifests as exhaustion, lack of drive, or inner withdrawal. This mechanism also originally serves protection, but in the long term it becomes burdensome.

WHEN REGULATION IS LOST

In everyday life, these states usually shift flexibly. This very flexibility is crucial for health.

Chronic stress, however, can impair this regulatory capacity. The body then either remains in a permanent state of activation or slips increasingly into a state of exhaustion.

Typical complaints that can accompany dysregulated nervous system function include:

• persistent exhaustion and reduced performance
• sleep disturbances
• functional digestive complaints
• increased susceptibility to stress

These symptoms are not only subjectively distressing, but also reflect changes at the physical level. Studies show that persistent stress can:

• promote inflammatory processes in the body
• influence hormonal balance
• make regeneration at the cellular level more difficult

One frequently studied marker in this context is the so-called heart rate variability (HRV). It provides information about how flexibly the nervous system can respond to stressors. Higher HRV is associated with better adaptability and a more stable state of health.

APPROACHES FOR EVERYDAY LIFE: HOW CAN THE NERVOUS SYSTEM BE SPECIFICALLY REGULATED?

The good news: The nervous system is adaptable. Even though phases of stress cannot always be avoided, the ability to regulate can be specifically supported.

The goal is not to eliminate stress completely – but to repeatedly send signals of safety to the body. These signals help the nervous system return from a state of constant activation back into balance.

The following strategies can help:

• Conscious breathing: Slow breaths with a prolonged exhalation act directly on the autonomic nervous system and can help reduce the stress response.

• Regular recovery phases: Short breaks in everyday life – even just a few minutes – can relieve the nervous system. What matters is regularity, not duration.

• Movement as stress regulation: Moderate physical activity, walks, or movement in nature support the breakdown of stress hormones and promote regulation of the nervous system.

• Social contact and connectedness: Positive interpersonal interactions send safety signals to the nervous system. Social connectedness therefore plays an important role in stress regulation.

• Recognizing warning signs early: Persistent exhaustion, sleep problems, increasing irritability, or the feeling of constant tension can be signs that the nervous system is under chronic strain. Noticing such signals early is an important step in taking countermeasures.

• Not just compensating for stress, but regulating it: Many people try to compensate for stress through short-term distraction. More sustainable, however, is strengthening one’s own regulatory capacity – the ability to consciously return to a state of calm and safety after strain.

These factors promote balance in the nervous system and can increase resilience to stress over the long term.

CONCLUSION

Health does not depend solely on avoiding stress. Much more decisive is the nervous system’s ability to switch flexibly between activation and regeneration.

The Polyvagal Theory expands the classical view of the sympathetic and parasympathetic systems and provides a more differentiated understanding of the connections between the nervous system and health.

At the same time, it shows: Regulation of the nervous system is not a static state, but can be actively supported through conscious everyday habits. Even small changes can help restore balance and become more resilient to stress in the long term.

REFERENCES

Principles of the Polyvagal Theory

• Porges, S. W. (2011). The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-Regulation. W. W. Norton & Company.
• Porges, S. W. (2007). The polyvagal perspective. Biological Psychology, 74(2), 116–143. https://doi.org/10.1016/j.biopsycho.2006.06.009

Autonomic nervous system, stress and physiology

• McEwen, B. S. (2007). Physiology and neurobiology of stress and adaptation: central role of the brain. Physiological Reviews, 87(3), 873–904. https://doi.org/10.1152/physrev.00041.2006
• Chrousos, G. P. (2009). Stress and disorders of the stress system. Nature Reviews Endocrinology, 5, 374–381. https://doi.org/10.1038/nrendo.2009.106

Stress, inflammation and hormonal regulation

• Slavich, G. M., & Irwin, M. R. (2014). From stress to inflammation and major depression. Psychological Bulletin, 140(3), 774–815. https://doi.org/10.1037/a0035302
• Black, P. H., & Garbutt, L. D. (2002). Stress, inflammation and cardiovascular disease. Journal of Psychosomatic Research, 52(1), 1–23. https://doi.org/10.1016/S0022-3999(01)00302-6

Heart rate variability (HRV)

• Shaffer, F., & Ginsberg, J. P. (2017). An overview of heart rate variability metrics and norms. Frontiers in Public Health, 5, 258. https://doi.org/10.3389/fpubh.2017.00258
• Thayer, J. F., & Lane, R. D. (2000). A model of neurovisceral integration. Biological Psychology, 74(2), 116–143. https://doi.org/10.1016/S0301-0511(00)00023-0