These involuntary reactions function, essentially, to discharge the vast energy that, though mobilized to prepare the organism to fight, flee or otherwise self-protect, was not fully executed.
Levine establishes discharge as the somatic mechanism by which thwarted survival energy is released through involuntary trembling and respiratory change, constituting the physiological core of trauma resolution.
, In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness, 2010thesis