•    What we experience when we face challenges in our lives
  •    External or internal stressors
  • Can be negative or positive  o Distress  Ex: Exams, divorce, deadlines

o Eustress  Ex: Marriage, graduation, job promotion

 

Causes of Negative Stress

  • Biological  o Substance abuse  alcohol, caffeine   o Nutritional excess  caffeine, sugar  
  • Psychological  o Perfectionist attitudes  o Obsessiveness-compulsiveness
  • Need for control
  •    Interpersonal
  • Lack of social skills, shyness, insecurity, loneliness o Environmental strain  noise, temperature  

  

General Adaptation Syndrome

  •     “Arousal and alarm” – Initial reaction to stress
  •    “Fight or flight response” for males and the “tend and befriend response” for females   adaptations to deal with crisis
  •     Anxiety, irritability, and vulnerability until stress is resolved
  • If the stressor is unresolved:  o Stage of Resistance – Strain, worry, cynicism, difficulty sleeping
  • If the stressor is prolonged:  o Stage of Exhaustion – Anxiety and depression

 

Stress Response

  •    Is initiated when some real or perceived threat or challenge is encountered

 

Vicious Cycle of Stress

  •    Cortex perceives what is going on
  •     Relayed to the amygdala  center for stress response
  •  Moves to an area in the brainstem  and CRH is released  and down to the adrenal  glands  where ACTH, epinephrine, norepinephrine, and cortisol is released   o If perceived as something negative, cortisol is released

o If perceived as something positive, epinephrine and norepinephrine are  released

  •    With chronic stress, this cycle constantly repeats between the adrenal glands and  brainstem

 

Stress Response Continued

  • Secretion of two kinds of hormones from the adrenal glands  o Catecholamines
  • Epinephrine E and norepinephrine  NE
  • When situation presents a challenge to an individual o Cortisol
  • When an individual is faced with a threat or unpleasant challenge
  • How much the person feels in control influences whether E and NE or cortisol is released

 

Homeostasis and Allostasis

  •    Homeostasis
  • Ability of an organism to change and stabilize its internal environment despite constant changes to the external environment  
  •    Allostasis
  • Wide range of functioning of coping-adaptation systems, depending on a variety of factors  time of day, internal needs, external demands, etc.  

 

Allostatic Load

  •     The cost of coping-adaptation
  •    Wear and tear on the brain and body
  •    Ongoing stress: Stress response never “turns off;” leads to illness and disease

o Ex: Chronic elevations of HR and BC can lead to decreased immune function,  memory loss, and increased risk of anxiety and depression

 

Combat Stress in Soldiers

  •   Morgan et al.  2001  documented stress in active-duty soldiers
  •    Experiment involved interrogations following a mock capture, food and sleep  deprivation, and problem solving
  • Resulted in elevated cortisol levels:  o Dissociated thinking, psychological disconnect from one’s environment, and  poor performance

 

Cross-Stressor Adaptation Hypothesis

  •    A stressor of sufficient intensity and-or duration will induce adaptation of stress  response systems
  • Exercise training is thought to develop crossCstressor tolerance by:  o Habituation: A decreased magnitude of response to some familiar challenge  o Sensitization: An augmented response to a novel stressor
  •    Exercise can be viewed as a familiar challenge and should influence the stress  response to nonCexercise stressors
  •    Ex: Increased fitness levels leads to decreased stress response in non-exercise  settings

 

Psychophysiology

  •    Examines cognitive, emotional, and behavioral events through their manifestation as  physiological processes and events
  •     Includes relatively non-invasive measures of many bodily systems:
  • EMG EEG, ECG
  • Endocrine and immune function

 

Measurement

  • SelfCreported Measurement  o Perceived Stress Scale  PSS : A questionnaire that measure the degree to  which situations in one’s life are viewed as stressful
  • Does not help to uncover the physiological mechanisms underlying the stress response
  • Use in conjunction with other physiological  measures

 

  • Cardiovascular Measurement  o Most frequently used physiological measurement
  • Heart rate and blood pressure are examined most  o Does not say why#changes occur

    Hormonal Measurement

  • Catecholamines epinephrine and norepinephrine  and cortisol  o Derived from plasma, urine and saliva  

 

Exercise and Stress

  •     People report feeling less stress following acute exercise bouts
  • They are less stressed in general when they are physically active as opposed to being  sedentary

 

Exercise-Stress Research 

  •    Effect of exercise on stress response studied in a variety of areas:
  • Cardiovascular Fitness
  • Hypothalamic-Pituitary-Adrenal HPA  Cortical Axis Response  o Immune Function
  • Reactivity vs. Recovery

 

 

Cardiovascular Fitness

  •     Results are inconclusive
  •    Mechanisms responsible for the sympathetic aspect of the psychosocial stress  response  Ex: Epinephrine and norepinephrine  and the response to exercise stress  may be different
  •    Research does suggest that aerobic fitness may have stress-buffering effects to  psychosocial stress  Ex: Lower resting heart rate

 

 

Hypothalamic-Pituitary-Adrenal  HPA  Cortical Axis Response

  • Traustadottir et al.  2005  compared fit and unfit older women’s responses to stress  tests:  o Found that fit women had lower cortisol response, but no differences for

ACTH  epinephrine and norepinephrine  and cardiovascular measures

o Concluded that aerobic fitness affects the HPA axis by reducing the cortisol  response to psychosocial stress

 

Immune Function

  •      LaPierre et al.  1990 : Men who exercises for five weeks before being told they were

HIV-positive had little change in psychosocial and immunological measures

  •    Control group showed significantly decreased killer cell activity as well as significant  anxiety and depression

 

 

Reactivity vs. Recovery

  •    Evidence suggests that fitness or exercise training may provide a more rapid  recovery from the stressor once it is no longer present
  •    Trained individuals: Lower heart rate response and decreased cortisol levels in  recovery
  •    Shorter duration of the stress response could have the effect of reducing the  allostatic load and overall wear and tear on the body

 

Mechanism to Explain the Exercise Effect: Physiological Toughness Model

  •     A psychophysiological framework
  •    Explains how exercise can reduce the immediate effects of stress and can enhance  recovery from stressors
  •    Intermittent but regular exposure to stressors  Ex: Regular exercise  can lead to  psychological coping, emotional stability, and physiological changes
  •    Physiological changes lead to adaptive performance in challenge-threat situations,  enhancement of immune system function, and greater stress tolerance
  •    Ex: Rapid epinephrine-norepinephrine release in response to stress and a quick  return to baseline levels when the stressor is removed

 

Practical Recommendations

  • Exercise can be a way of dealing with daily stressors of life  o Morning Exercise: Help get one ready to face the day’s challenges  o Noontime Workout: Provide a much needed break in the day to recharge  batteries

o Evening Workout: Useful to purge tensions and worries of the day