Stress a state of disharmony or threatened homeostasis what we experience when we face challenges in our lives STRESS Stressors o External physical threats o Internal ex fear of public speaking Distress negative stress exam divorce deadlines Eustress positive marriage graduation job promotion Hans Selye Tested rats Would try to inject them but was unsuccessful and would chase them around the lab Rats who were exposed to a variety of unpleasant conditions developed many physiological changes peptic ulcers enlarged adrenal glands atrophied immune tissues General Adaptation Syndrome o Acute short term stressor o Arousal and alarm o Fight or flight o Tend and befriend Responses to Stress Stress response when some real or perceived threat is encountered The brain sends a message to the amygdala which activates the hypothalamus Hormones are released which initiate the fight or flight response Homeostasis o Balancing of the body s physiological systems thus furthering the concept of the milieu interieur o Ability of an organism to change and stabilize its internal environment in spite of constant changes to the external environment Allostasis o Achieving stability through change in a wide range of functioning o For recent addition to stress literature o Homeostasis relates to systems needing to maintain life and allostasis reflects the balance these essential coping adaptation systems maintain depending on a variety of factors time of day internal needs aging external demands o Allostatic Load The costing of this coping adaptation Wear and tear on the brain and body Occurs when the SAM or HPA systems become overworked because of chronic or unrelenting stress The SAM and HPA systems are most useful when responding rapidly to a stressor then turn off as soon as they are no longer needed Results in illness or disease Elevated HR BP metabolism leading to decreased immune function memory loss increased risk of anxiety anorexia chronic fatigue and fibromyalgia 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 cross stressor tolerance through either o Habituation seeing a decreased magnitude of response to some familiar challenge o Sensitization seeing an augmented response to a novel stressor Exercise can be seen as a familiar challenge and can influence stress response Measurement Psychophysiology is a prominent area in the domain of exercise psychology Self report measurement o Perceived Stress Scale measures the degree to which situations in one s life are viewed as stressful Not very helpful to uncover underlying physiological mechanisms Cardiovascular measurement o Most frequently used physiological measures o HR BP Hormonal Measurement o Assessment of catecholamines and cortisol o Measured using saliva plasma and urine samples o Cortisol peaks before waking up in the morning Human exercise Cardiovascular fitness o Crews and Landers found that despite how stress response was measured more fit individuals had smaller stress responses than unfit o Meta analysis study Examines the effects of physical fitness of cardiovascular reactivity and recovery from psychosocial stressors Found evidence contradicting Crews and Landers Evidence does not support hypothesis of reduced reactivity to stressors in more fit individuals Found that more fit individuals have a faster recovery following stressor o Absolute reactivity absolutely value of HR during stress o Relative reactivity change in HR during stress from a baseline value