Week 4 - Stress & Health Flashcards
Stress has been defined in three ways:
As a stimulus, a response, and a transaction
What is stress in terms of a stimulus?
Things that happen in your environmental/life that attribute stress to; stressors.
What is the Life Events Theory (The Social Readjustment Rating Scale classic study, Holmes & Rahe 1967)?
Asked over 5000 people “what do you find stressful” then assigned units called Life Change Units. People who recorded 150-300 LCUs in 50% of the cases, were found to have an ill health event in the subsequent 6 months. More than 300 LCUs, likelihood of illness went up to 80%.
What are the limitations of the Life Events Theory?
Does establish an association between stress (from positive or negative events) and health. They tried to standardize but… LCUs were assigned regardless of desirability of event. Age bias in likelihood of life event experience (e.g. childbirth, divorce, etc.). Events may simply not occur (i.e. low frequency). Intertwined life events may cancel out a LCU (e.g. new job & move house). Fails to address the moderators of stress (e.g. individual appraisal of events). The study was retrospective, so possible recall bias by only recalling the most salient of events.
What was the Hassles Scale (Kanner et al. 1981)?
Defined daily hassles as things that can affect your day-to-day mood or functioning (e.g. missing the bus, caught in the rain). Study looked at an accumulation of daily hassles in relation to mental and physical health. Counterbalanced hassles with uplifts (i.e. good conversation, finishing a task, gaining something, losing weight, etc.). They found that the same potential stimuli of stress can be responded to differently depending on things like age and experience (i.e. socializing was highly salient in young people and old people, not middle-age professional adults). The event alone is insufficient explanation of the stress response.
What are the three waves of the stress response?
Activation of the sympathetic nervous system, endocrine response, and immune response.
What is the fight-or-flight response (Cannon 1932)?
When an organism experiences a shock or perceives a threat, it quickly releases hormones that help it to survive. In humans, these hormones increases heart rate and blood pressure to deliver more oxygen and blood sugar to important muscles, increases sweating to cool these muscles, and diverts blood away from skin to core to reduce blood loss.
What does the sympathetic nervous system do?
It looks at initial arousal response by relaxing bronchi, accelerating heart beats, strengthens heart contractions, inhibits stomach activity, stimulates glucose release by liver and secretion of catecholamines.
What does the parasympathetic nervous system do?
This sytem calms things down. It constricts bronchi, slows heart beat, decreases blood pressure, and stimulates stomach activity.
Activation of the SNS and PNS are seen as what kind of reactions?
Adaptive reactions that enable us to deal with acute threats whilst maintaining an equilibrium or homeostasis.
Prolonged physiological arousal due to stress is associated with what kind of diseases?
Diseases of adaptation (e.g. stomach ulcers, IBS, asthma)
What are the two main systems involved in the endocrine (hormonal) response to stress?
Sympathoadreno-medulary system (SAM) and hypothalamic-pituitary-adrenal cortical system (HPAC)
Describe the SAM system.
Stress activates the SNS, which activates SAM, causing catecholamines to be released from the adrenal medulla. These hormones enlarge our autonomic responses (e.g. rapid breathing releases fuel for energy) and facilitate the release of stored fuels for energy (i.e. the fight or flight reaction). Cannon focused on this response.
What does the secretion of catecholamines cause?
Increase in heart rate, blood pressure, and breathing rate, blood is diverted to muscle tissue, digestion slows down, and pupils of eyes dilate. These are shortlived responses.
Describe the HPAC system.
Stress activates the SNS, which tells the hypothalamus to activate the HPAC system, causing the pituitary gland to produce corticotrophins, which causes adrenal cortex to release adrenaline and noradrenaline. This stimulates glucocorticoid secretion, which leads to corticosteroid production (cortisol). Cortisol fights inflammation and inhibits glucose uptake so that glucose can be used for energy (maintain carbohydrate storage). Selye focused on this response.
What does the secretion of corticosteroids cause?
Increases protein and fat mobilization and access to bodily energy storage, inhibition of antibody formation and inflammation, and regulates sodium retention. Resulting from the HPAC system; this is involved in beta-endorphine, our natural pain killers/opiates. Too much cortisol production in the blood stream can be maladaptive to our immune system. This is not an acute response but a longer, slower, more prolonged stress response.
Who coined the term ‘stress’?
Hans Selye (1936) discovered that the human body shows a non-specific, typical response to any toxic substance or demand. This nonspecific response was defined as stress.
What are the three stages of Selye’s (1950) General Adaptation Syndrom (GAS)
In response to a stressor, the first stage is the alarm reaction, which mobilizes the body’s resources to meet the threat (fight-or-flight, SAM activity, increased heart rate, etc.). This is adaptive but can be maladaptive over longer periods of time. The stage of resistance is when the physical effects are replaced by other physiological activity (increased blood pressure, release of hormone, adrenaline to increase energy to cope with stressor), and the stage of exhaustion that occurs if the stressor is chronic. This may deplete our immune response and cause diseases of adaptation.
What are the limitations of Selye’s approach?
Doesn’t acknowledge that some stressors simply do elicit stronger responses. Doesn’t acknowledge role of cognitive appraisal (i.e. a persons perceptions of a situation mediate their response). It treats good or bad stressors in the same way. Only allows stress to lead to disease if the adaptive responses are required for long periods of time… HOWEVER, links are shown between acute stressors or anticipation of stressor and debilitating effects of health (mental and physical). Primarily based on animal research, so limited integration of the role of the mind.
What is the immune response following stress?
Produces lymphocytes and phagocytes (types of white blood cells) in response to chemical messages our body sends off because of pathogen or stress. We become immunosuppressed during stress, for instance, people under prolonged stress cannot fight wounds or bacteria as well.
What is the bottom-up approach to modeling stress?
Exercise produces pronounced cardiovascular and endocrine responses (e.g. increased peripheral blood flow, adrenaline, cortisol) = physical stress.
