Exercise and Psychological Stress Flashcards
Stress response
How the body reacts when encountering a real, perceived or expected threat
- Involves both psychological and physiological elements
Amygdala
Primary subcortical brain structure responsible for initiating the stress response
Homeostasis
The ability to balance/stabilize one’s internal environment despite changes to the external environment
- Narrow range for optimal function
Allostasis
Achieving stability through change
- Balancing essential coping/adaptation systems depending on a variety of factors
- Can achieve homeostasis through allostasis
Allostatic Load
The cost of this adaptation/coping
- Applies to stress (overwork SAM or HPA)
- Under chronic stress neither axis turns off after stress is removed
- Wear and tear on the brain and body
- may lead to decreased immune function, memory loss, mental health disorders
Allostasis and allostatic load
Disruption to homeostasis requires a physiological response
- ALLOSTASIS: physiological response
- ALLOSTATIC LOAD: cost of response (area under the curve)
NUTS model
Novelty
Unpredictability
Threat to ego
Sense of control
- Used to asses degree of stress from situation
Cognitive-Transactional Model of Stress
Physical and psychological stressors
- Leads to primary appraisal (stressor pose a threat) and then secondary Appraisal (can i handle it) then reappraisal
Sympathetic Adrenal Medullary Axis
- Stressor
- Cerebral cortex
- Amygdala
- Hypothalamus
- Sympathetic Nervous system
- Adrenal medulla
- Release epinephrine and norepinephrine
- Responds to Challenge
Effects of epinephrine and norepinephrine
- Increase blood pressure
- Increase HR
- Increase alertness and arousal
- decreased digestion/ blood flow to splanchnic region
Effects of cortisol
- Increase blood glucose
- Increased glucose utilization by the brain
- suppressed digestion
- suppressed immune function
Hypothalamic Pituitary Adrenocortical axis
- Stressor
- Cerebral cortex
- Amygdala
- Hypothalamus
- Corticotropin-Releasing Hormone
- Pituitary Gland
- Adrenal Cortex
- Release of cortisol
- Responds to threat or unpleasant challenge
Beta-blockers
- Drug that blocks action of norepinephrine on beta-adrenergic receptors in heart
- Prevents stress-induced heart rate increases
How can we create stress in a lab setting?
Through active and passive stressors
ACTIVE STRESSORS
- Stroop color-word test, mental arithmetic, public speaking
PASSIVE STRESSORS
- Painful, loud, startling stimuli
- Watching emotionally negative films or images
How do we measure the stress response
SELF-REPORT
- measures using validated questionnaires
- Assess magnitude and frequency of perceived stress
- PRO: can asses large groups
- CON: cannot assess underlying physiological response
HORMONES
- Measure EPI, NE, and cortisol in blood or saliva
- CONS: methods of measuring may induce stress, hormones naturally fluctuate throughout the day
CARDIOVASCULAR RESPONSE
- Increase in HR or Blood pressure
Cardiovascular response to stress mechanism
- Increased SNS activity leads to increased release of norepinephrine
- Acts on alpha 1-adrenergic receptor causing vasoconstriction
- Sympathetic nervous system directly stimulates increased HR
Cross-Stressor Adaptation Hypothesis
Exposure to a stressor of sufficient intensity and/or duration will induce adaptation and decreased sensitivity or stress response system
- Leads to habituation, which means lower stress reactivity and faster stress recovery
Study on how exercise training reduces stress
- Fit vs unfit men perform mental arithmetic test (Stressor) and BP and HR are measured
- Unfit performed 5 wk of exercise training 3x/week at mod intensity
- Reduction in HR and BP post training
What is the optimal does of exercise for reduced anxiety
Length: 3 to 6 weeks of training
Frequency: 3-4x per week
Duration: 20-30 min = largest decrease in anxiety
How does mental health state affect reductions in anxiety with exercsie
- Anxiety decreases greater in people without anxiety disorders
Resistance training and anxiety
- RT significantly reduces anxiety symptoms
- Type of RT not important
- Greater effects observed in healthy population
- Still beneficial with anxiety disorders
How do RT and AT differ in their reductions of anxiety
No difference
Exercise Training and Depression Prevention
Exercise training decreases depression symptoms across the lifespan
- Can act as effecting prevention took
- Exercise is as effective as traditional therapies
Exercise, medication or both in patients with MDD study
- 156 adults with diagnosis of MDD either trained in 4 month 3x/w aerobic training, took antidepressants or both
- Exercise lowers depression to the same extent as medication
- Compared with participants in the other conditions, those in the exercise condition were more likely to be partially or fully recovered and were less likely to have relapsed
What is the optimal prescription of exercise for MDD
MODE: Doesn’t matter; aerobic or resistance exercise
Intervention length: at least 10 week (although changes are see earlier)
Frequency: 3 to 5x per week
Intensity: Aerobic - 50-85% of max HR, resistance - higher intensity
Duration: 30 to 60 min per session
- Consider personal preference and activity in green space
Mastery Hypothesis
- Psychological benefits from feelings of accomplishment or mastery post-exercise
- Mastery gives a sense of greater self-worth and personal control over the environment
Neurochemical +neurogenesis hypothesis
- Brain evolved mechanisms that stimulate adaptation in response to physical and cognitive demands - adaptation increases resilience and resistance to stress
-Exercise increases opioids, endorphins and endocannabinoids (may also restore balance of neurotransmitters that are altered with depression - Exercise increases brain-derived neurotropic factor (BDNF) - stimulates neurogenesis in the hippocampus
BDNF and Depression
- Blood concentrations of BDNF significantly decrease
- Anti-depressant treatment significantly increases BDNF
- increased BDNF associated with decreased depression scores following treatment
- BDNF is a biomarker for depression improvement after anti-depressant treatment
