Flight or fight

• A physiological reaction that occurs in response to a perceived threat. There are two systems for the stress response; acute stressors and chronic stressors.
• Acute stressors are sudden that unexpected and triggers the sympathetic nervous system
• Chronic stressors are on going stress that triggers HPA
• The SNS is responsible for the 'fight or flight' response, which prepares us to either confront danger (fight) or run away from it (flight). It does this by releasing adrenaline into our bloodstream.
• Adrenaline increases heart rate, breathing rate, blood pressure, muscle strength and alertness. This allows us to respond quickly to threats.
• The parasympathetic nervous system has an opposite effect to the SNS. When we feel safe again, the PNS slows down our body functions so they return to normal levels.
• When we experience long-term stress, the hypothalamic pituitary adrenocortical axis becomes involved. The hypothalamus releases corticotrophin-releasing hormone (CRH), which stimulates the anterior pituitary gland to release adrenocorticotropic hormone (ACTH)
• Stress can have both positive and negative effects on health. Short term stress can improve performance but prolonged exposure to stress hormones can lead to physical and mental illness.