Acute Stress Response

Acute stress response is an immediate, involuntary physiological and psychological reaction triggered by a perceived mental or physical threat. Initiated by the brain’s amygdala, it prompts the sympathetic nervous system (SNS) to flood the body with stress hormones like adrenaline and cortisol. This cascade causes rapid heartrate, heightened alertness, quickened breathing, and a redirection of blood flow to major muscle groups to maximize survival odds. Modern psychological models note that this response generally manifests through distinct behavioral survival mechanisms, colloquially known as the 4 Fs: Fight (aggression), Flight (escape), Freeze (immobility), or Fawn (appeasement). Also see: Fight-or-Flight Response (FFR)