Lesson 1: Physiological & psychological characteristics of responses to stress
Exposure to stressful situations and events is a common human experience. From losing your locker key to losing your job – these events can produce stress.
Stressor = any person, situation or event that produces stress. Virtually anything can be a stressor and therefore a cause of stress to an individual.
Stress and Health
Stress =A state of physiological and psychological arousal produced by internal or external stressors that are perceived by the individual as challenging or exceeding their ability to cope.
Responses to Stress
Stress affects different people in different ways – depending on severity, duration and the individual.
A Stress Response = physiological (bodily) and psychological (mental) changes experienced when confronted by a stressor.
Stress&can&be&classified&as&MILD,&ACUTE&or&CHRONIC.&
Mild&stress&&?&can&be&s@mula@ng&–&low&levels&of&arousal&can&enhance&performance.&Acute&–&sudden&high&arousal&level.&Chronic&–&long&term&–&can&be&damaging.&&
Eustress and Distress
Eustress is a positive psychological response to a stressor, as indicated by the presence of positive psychological states such as feeling enthusiastic, excited, active and alert. Distress, on the other hand, is a negative psychological response to a stressor, as indicated by the presence of negative psychological states such as anger, anxiety, nervousness, irritability or tension.
Physiological (Bodily) Responses to Stress • The$second$model$which$addresses$the$physiological$responses$to$stress$is$$
the$General$Adapta-on$Syndrome.!
2.#General#Adapta.on#Syndrome#
General'Adapta,on'Syndrome'=''A"three"stage"physiological"stress"response"that"occurs"regardless"of"the"stressor"that"is"encountered."There"are"three"stages"in"the"GAS"–"Alarm"Reac;on,"Resistance"and"Exhaus;on.""
Research"by"Hans"Selye.""
Physiological (Bodily) Responses to Stress 2.#General#Adapta.on#Syndrome#
• Cannon’s'belief'that'prolonged'stress'is'harmful'was'confirmed'by'Selye.''
• Most'of'Selye’s'stress'studies'used'rats'who'were'exposed'to'a'variety'of'stressors.'(eg.'Tail'pulling,'electric'shocks'etc).'
• Regardless'of'the'stressor,'the'results'were'relaDvely'similar'–'enlarged'adrenal'glands,'weight'loss,'stomach'ulcers'and'depleted'immune'system'etc.''
• He'then'concluded'that'stress'is'nonGspecific.''• Humans'reacted'in'much'the'same'way'to'stress.''
• Based'on'his'studies,'Selye'develop'the'three'stage'• 'GENERAL'ADAPTATION'SYNDROME.''
Physiological (Bodily) Responses to Stress 2.#General#Adapta.on#Syndrome#(GAS)#
There%are%three%stages%in%the%GAS.%
Stage%One:%Alarm%Reac6on:%!Occurs!when!the!person/animal!is!first!exposed!to!the!stressor.!!
• Body!goes!into!temporary!state!of!‘shock’!–!body!temp!and!blood!pressure!drop.!!
• The!body!then!quickly!rebounds!from!this!during!what!is!called!‘countershock’.!
• SympatheCc!NS!is!acCvated!and!a!reacCon!like!that!of!the!flightGflight!response!occurs.!Arousal!is!produced!by!the!release!of!hormones!by!the!endocrine!system:!the!pituitary!glands!secrete!ACTH,!which!causes!a!heightened!release!of!adrenaline,!noradrenaline,!and!corCsol!by!the!adrenal!glands!into!the!bloodstream.!!
• Organism!is!alert!and!ready.!%
The body cannot stay in this state for long without serious consequences. Some organisms in a continuous state of alarm have died within hours or days
Physiological (Bodily) Responses to Stress
2.#General#Adapta.on#Syndrome#(GAS)#
There%are%three%stages%in%the%GAS.%
Stage%Two:%Resistance:%%• If#the#reac*on#con*nues#and#is#not#strong#enough#to#cause#death#the#
physiological#reac*on#enters#the#stage#of#resistance.##• The#body#tries#to#adapt#to#the#stressor.#Physiological#arousal#declines#but#
remains#higher#than#normal#and#the#body#replenishes#the#hormones#released#by#the#adrenal#glands.##
• The#organism#may#show#few#outward#signs#of#stress.#However,#the#body#may#not#be#able#to#resist#new#stressors.##
• The#body#becomes#increasingly#vulnerable#to#health#problems.#These#health#problems#include#ulcers,#high#blood#pressure,#asthma,#and#illnesses#that#result#from#impaired#immune#func*on.#
Physiological (Bodily) Responses to Stress
2.#General#Adapta.on#Syndrome#(GAS)#
There%are%three%stages%in%the%GAS.%
Stage%Three:%Exhaus4on:%%• Severe%long*term%or%repeated%stress%will%cause%the%organism%to%enter%the%
third%stage,%the%stage%of%exhaus9on.%%• The%immune%system%and%the%body's%energy%reserves%are%weakened%un9l%
resistance%is%very%limited.%%• If%the%stress%con9nues,%disease%and%physiological%damage%become%
increasingly%likely%and%death%may%result.%