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Sympathovagal Tone

Meaning

Sympathovagal Tone is the precise, dynamic balance between the two primary branches of the autonomic nervous system: the sympathetic (fight-or-flight) and the parasympathetic (rest-and-digest, mediated largely by the Vagus nerve) systems. This tone is a critical physiological indicator of an individual’s capacity to adapt to stress, regulate internal organ function, and maintain allostatic balance. Optimal sympathovagal tone is characterized by a flexible, rapid shift between these two states, reflecting resilience and robust cardiovascular and metabolic health.