A stressor is a chemical or biological agent, environmental condition, external stimulus or an event seen as causing stress to an organism.
Chronic pain and impairment requiring medical attention may result from extreme physical stressors or if there is not sufficient recovery time between successive exposures.
Stressors occur when an individual is unable to cope with the demands of their environment (such as crippling debt with no clear path to resolving it).
[2] Generally, stressors take many forms, such as: traumatic events, life demands, sudden medical emergencies, and daily inconveniences, to name a few.
If the shock was pushed past a certain extreme after a particular period in time ASD can develop into what is commonly known as Post-traumatic stress disorder (PTSD).
Stress hormones travel in the blood stream to relevant organs, e.g., glands, heart, intestines, triggering a flight-or-fight response.
Between this flow there is an alternate path that can be taken after the stressor is transferred to the hypothalamus, which leads to the sympathetic nervous system; after which the adrenal medulla secretes epinephrine.
[14] The pathologies caused by the lack of predictability are experienced by some individuals working in fields of emergency medicine, military defense, disaster response and others.
[16] In knowing when a potential stressor will occur (such as an exam), the individual could, in theory, prepare for it in advance, thus decreasing the stress that may result from that event.