Selye initially recognized that irritating substances initiate an immune reaction mediated by HPA-axis activation. He later recognized that external factors also can trigger an equivalent immune reaction and influence health. He called these factors stressors, no matter them being experienced during a positive or negative way. additionally , Porges demonstrated the mixing of the multiple pathways of the vagal system in reference to stressors on organ function (polyvagal theory), visceral regulation, and emotional responsiveness .
Stressors influence cellular function by modulating organic phenomenon . the discharge of primary neuropeptides, neurohormones, and neurotransmitters results in the assembly of hormones and cytokines , which influence the proteomic and metabolic network pathways. When dysregulated or perturbed beyond the adaptive capacity of the system, stressors may ultimately end in the emergence of diseases .
At the experiential level, the brain incorporates the perception and appraisal of the present environmental experience . If a private perceives greater coping ability (e.g., more resources or skills) than things demands, the body will likely mount an appropriate physiological response, meaning activation with quick recovery. However, if a private decides their ability to cope whether conscious or subconscious is smaller than the stress of things , the interpretation results in a loss of control—the importance of which has been highlighted by Antonovsky —or threat to self. This perceived threat may cause excessive activation of the strain systems and exaggerated parasympathetic withdrawal.